H+ 

Cu2+ ON THE COVER 

Neutron powder diffraction pattern of a chabazite 

zeolite that is a good candidate for CO2 absorption, 

indicating high selectivity sites. 

See the highlight article by Hudson et al. on p.16 
 2012 ACCOMPLISHMENTS AND OPPORTUNITIES

NIST Center for Neutron Research 

2012 

Accomplishments 

and 

Opportunities 

NIST Special Publication 1143 

Robert M. Dimeo, Director 

Ronald L. Cappelletti, Editor 

December 2012 

National Institute of Standards and Technology 

Patrick Gallagher, Under Secretary of Commerce 

for Standards and Technology, Director 

U.S. Department of Commerce 

Rebecca Blank, Acting Secretary 
NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH

DISCLAIMER 

Certain commercial entities, equipment, or materials may be 

identified in this document in order to describe an experimental 

procedure or concept adequately. Such identification is not 

intended to imply recommendation or endorsement by the 

National Institute of Standards and Technology, nor is it 

intended to imply that the entities, materials, or equipment 

are necessarily the best available for the purpose. 

National Institute of Standards and Technology 

Special Publications 1143 

Natl. Inst. Stand. Technol. Spec. Publ. 1143, 92 pages 

(December 2012) 

CODEN: NSPUE2 

U.S. GOVERNMENT PRINTING OFFICEWASHINGTON: 2012 

For sale by the Superintendent of Documents, 

U.S. Government Printing Office 

Internet: bookstore.gpo.gov 

Phone: 1.866.512.1800 

Fax: 202.512.2104 

Mail: Stop SSOP 

Washington, DC 20402-0001 
This page intentionally left blank 

so that highlight articles can be 

displayed as two pages side-byside. 
 2012 ACCOMPLISHMENTS AND OPPORTUNITIES

Table of Contents
 

FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
 

THE NIST CENTER FOR NEUTRON RESEARCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
 

NIST CENTER FOR NEUTRON RESEARCH INSTRUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
 

NCNR IMAGES 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
 

HIGHLIGHTS 

ARCHEOLOGY 

Foreigners or not: new data prior to the Maya collapse in the western lowlands of mesoamerica, 

R. Bishop, et al. ........................................................................ 6 


BIOLOGY 

Walking the line between life and death: membrane binding and regulation of 


the PTEN tumor suppressor, S. S. Shenoy, et al. ............................................... 8 


Towards the elucidation of antiboitic resistance transfer in bacteria: structural studies 


of the Tral protein, N.T. Wright, et al. (CHRNS) ............................................. 10
 

Structures and conformations of voltage-sensor domains and voltage-gated K+ 


channel proteins, S. Gupta, et al. .......................................................... 12
 

The role of electrostatic interactions in the local dynamics of biological and 


synthetic polyelectrolytes, J.H. Roh, et al. (CHRNS) ........................................... 14
 

CHEMICAL PHYSICS 

Powder neutron diffraction reveals new CO2 adsorption interactions in chabazite 


zeolites, M.R. Hudson, et al. (CHRNS) .................................................... 16
 

Evolving structure of the solid electrolyte interphase in Li-ion batteries characterized 


by in situ neutron reflectometry, J.A. Dura, et al. .............................................. 18 


Activated dihydrogen bonding to a supported organometallic compound, 

J.M. Simmons, et al. (CHRNS) .......................................................... 20
 

CONDENSED MATTER 

Electronic delocalization in the correlation gap insulator LaMnPO, J.W. Simonson, et al. ............... 22 


Spin-orbital short-range order on a honeycomb-based lattice, S. Nakatsuji, et al. (CHRNS) ............. 24 


Common origin of the two types of magnetic excitations in iron chalcogenide 


superconductors, Songxue Chi, et al. (CHRNS) .............................................. 26
 

Correlation between spin-flop transition and enhanced spin polarized supercurrents in 


ferromagnetic Josephson junctions, C. Klose, et al. ............................................ 28 


Charge ordering and magnetic frustration in the fluoride pyrochlore, RbFe2+Fe3+F6, S.W. Kim, et al. ...... 30
 

Table of Contents
 
NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH

 

 

Table of Contents


Table of Contents
 

ENGINEERING 

Measuring yield stresses in biaxial deformation, T. Gnäupel-Herold, et al. ........................... 32 


NEUTRON PHYSICS 

A new limit on time-reversal violation in beta decay, H.P. Mumm, et al. ............................ 34
 

SOFT MATTER 

Self-assembling organohydrogels: liquid dispersions with solid-like behavior, 

M.E. Helgeson, et al. (CHRNS) .......................................................... 36 


Thickness fluctuations in model membranes, A.C. Woodka, et al. (CHRNS)......................... 38 


Electrochemical Small-Angle Neutron Scattering (eSANS) for studies of nanoparticle 


redox reactions, V.M. Prabhu, et al. (CHRNS) ............................................... 40 


Identifying the shape of copper-seamed nanocapsules in solution, H. Kumari, et al. (CHRNS) .......... 42 


Characterizing dense polymer-nanoparticle mixtures by neutron scattering, S.Y. Kim, et al. (CHRNS) ..... 44 


ADVANCES IN MEASUREMENT 

A Liquid Deuterium Cold Neutron Source for the NBSR, R.E. Williams, et al. ...................... 46 


EXPANSION ACTIVITIES DURING THE PLANNED OUTAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 


NEUTRON SOURCE OPERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 


FACILITY DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 


SERVING THE SCIENCE AND TECHNOLOGY COMMUNITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 


THE CENTER FOR HIGH RESOLUTION NEUTRON SCATTERING (CHRNS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 


2012 AWARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
 

PUBLICATIONS: AUGUST 1, 2011 TO JULY 31, 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 


INSTRUMENTS AND CONTACTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 


NIST CENTER FOR NEUTRON RESEARCH CONTACTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (inside back cover)
 
 2012 ACCOMPLISHMENTS AND OPPORTUNITIES

Foreword
 

Foreword
 

I

t is with pleasure that I present this year’s annual report for the NIST Center for Neutron Research. 

When looking back over the last year, the only word that I can use to describe this time period is 

dynamic. User operations were successful and productive, the reactor operating for 142 days out of a 

scheduled 142 days. The cold source continued to operate reliably and deliver neutrons 99 % of the 

scheduled operating time. This period was marked by considerable scientific productivity and impact as the 

highlights in this report illustrate. The productivity is due to many factors, but it is worth noting that the 

number of user experiments on the MACS spectrometer continued to grow as the amount of time available 

to the user community was increased, industrial research participation on many of the neutron instruments, 

especially uSANS, was strong, and research opportunities with other laboratories grew, particularly in the area 

of biology and biosciences. Moreover, significant progress was made towards bringing the isotope labeling laboratory on line which will 

certainly prove to be a valuable resource for NCNR users. 

This year was also marked by a period of many facility enhancements that can best be described as historic. On April 3, the reactor shut 

down, as planned, for a period of 11 months. As I described in last year’s annual report this outage was scheduled in order to execute 

many tasks towards the expansion of our cold neutron measurement capability and enhance the reliability of the reactor. A few of the 

activities include installation of a new neutron guide system in our expanded guide hall which will hold new and relocated instruments, 

installation of a new cold source dedicated to the MACS instrument, relocation of MACS, and installation of a new cooling system for 

the reactor’s thermal shield. In addition significant construction in and around the site has taken place during the outage, including 

the construction of a new secondary cooling system, the addition of a new cooling tower cell, and additional electrical capacity. The 

commencement and execution of this outage marks the culmination of a significant amount of planning and coordination as well 

as the hard work and diligent efforts of our staff, especially those from Reactor Operations and Engineering and Research Facility 

Operations. You can read more about the progress we have made during the outage within this report and on our website: http://www. 

ncnr.nist.gov/expansion2/ where you will find technical details and photos. I am also pleased to inform you of the release this year of an 

informal history, “The NIST Center for Neutron Research: Over 40 Years Serving NIST/NBS and the Nation”, by Jack Rush and Ron 

Cappelletti, NIST Special Publication 1120. Contained therein is an account of major events of the NCNR spanning the period from 

conception of the NIST reactor to the NCNR Expansion Project. 

As of this writing we just announced our first call for proposals for experiments to be run upon restart of the reactor. In just a few short 

months the reactor will restart and users will return to the NCNR. The reason for the outage and expansion is for you, our users. I 

am looking forward to restoration of user operations and especially offering new measurement capabilities that our expansion project 

will provide through the coming year. I invite you to take a look at the research highlights from the past year as well as the description 

of what we have been up to during the outage. As you read through this report, I hope you get the same sense of excitement and 

opportunity that we are all feeling here. 

iii 
A view of new guides emerging into the guide hall in a Nov . 6, 2012 photo The group of people is standing by NG-D, emerging through the square hole 

just to their right . Behind them are shields blocking the view of the newly installed PBR and MAGIk instruments, taking beams off the side of NG-D The 

guide visible just behind the striped safety marker is NG-C, and to its right, emerging from NG-Blower, is the tank of the 10 m SANS instrument being 

installed . NG-Bupper is behind the two grey shields to the left of the tank . Not visible is NG-A, to the right of the 10 m SANS, still under development 

iv N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 2012 ACCOMPLISHMENTS AND OPPORTUNITIES 1 

 

 

The NIST Center for Neutron Research
 

Neutrons provide a uniquely effective probe of 

the structure and dynamics of materials ranging 

from water moving near the surface of proteins to 

magnetic domains in memory storage materials. 

The properties of neutrons (outlined at left) can be exploited 

using a variety of measurement techniques to provide 

information not otherwise available. The positions of atomic 

nuclei in crystals, especially of those of light atoms, can 

be determined precisely. Atomic motion can be directly 

measured and monitored as a function of temperature or 

pressure. Neutrons are especially sensitive to hydrogen, 

so that hydrogen motion can be followed in H-storage 

materials and water flow in fuel cells can be imaged. 

Residual stresses such as those deep within oil pipelines 

or in highway trusses can be mapped. Neutron-based 

measurements contribute to a broad spectrum of activities 

including in engineering, materials development, polymer 

dynamics, chemical technology, medicine, and physics. 

The NCNR’s neutron source provides the intense, conditioned 

beams of neutrons required for these types of measurements. In 

addition to the thermal neutron beams from the heavy water or 

graphite moderators, the NCNR has a large area liquid hydrogen 

moderator, or cold source, that provides long wavelength guided 

neutron beams for the major cold neutron facility in the U.S. 

There are currently 27 experiment stations: four provide 

high neutron flux positions for irradiation, and 23 are beam 

facilities most of which are used for neutron scattering research. 

The subsequent pages provide a schematic description of our 

instruments. More complete descriptions can be found at 

www.ncnr.nist.gov/instruments/. Construction of a second guide 

hall is now complete (see p. 47) and five new instruments are 

under development. 

The Center supports important NIST measurement needs, but 

is also operated as a major national user facility with meritbased access made available to the entire U.S. technological 

community. Each year, about 2000 research participants from 

government, industry, and academia from all areas of the country 

are served by the facility (see p.57). Beam time for research to 

be published in the open literature is without cost to the user, 

but full operating costs are recovered for proprietary research. 

Access is gained mainly through a web-based, peer-reviewed 

proposal system with user time allotted by a beamtime allocation 

committee twice a year. For details see www.ncnr.nist.gov/ 

beamtime.html. The National Science Foundation and NIST 

co-fund the Center for High Resolution Neutron Scattering 

(CHRNS) that operates six of the world’s most advanced 

instruments (see p. 60). Time on CHRNS instruments is made 

available through the proposal system. Some access to beam time 

for collaborative measurements with the NIST science staff can 

also be arranged on other instruments. 

Why Neutrons? 

Neutrons reveal properties not readily probed by 

photons or electrons . They are electrically neutral 

and therefore easily penetrate ordinary matter . They 

behave like microscopic magnets, propagate as 

waves, can set particles into motion, losing or gaining 

energy and momentum in the process, and they can 

be absorbed with subsequent emission of radiation to 

uniquely fingerprint chemical elements . 

WAVELENGTHS − in practice range from ≈ 0 .01 nm 

(thermal) to ≈ 1 .5 nm (cold) (1 nm = 10 Å), allowing the 

formation of observable interference patterns when 

scattered from structures as small as atoms to as large 

as biological cells . 

ENERGIES − of millielectronvolts, the same magnitude 

as atomic motions . Exchanges of energy as small 

as nanoelectronvolts and as large as tenths of 

electronvolts can be detected between samples and 

neutrons, allowing motions in folding proteins, melting 

glasses and diffusing hydrogen to be measured . 

SELECTIVITY − in scattering power varies from nucleus 

to nucleus somewhat randomly . Specific isotopes 

can stand out from other isotopes of the same kind 

of atom . Specific light atoms, difficult to observe with 

x-rays, are revealed by neutrons . Hydrogen, especially, 

can be distinguished from chemically equivalent 

deuterium, allowing a variety of powerful contrast 

techniques . 

MAGNETISM − makes the neutron sensitive to the 

magnetic moments of both nuclei and electrons, 

allowing the structure and behavior of ordinary and 

exotic magnetic materials to be detailed precisely . 

NEUTRALITY − of the uncharged neutrons allows 

them to penetrate deeply without destroying samples, 

passing through walls that condition a sample’s 

environment, permitting measurements under 

extreme conditions of temperature and pressure . 

CAPTURE − characteristic radiation emanating from 

specific nuclei capturing incident neutrons can be used 

to identify and quantify minute amounts of elements 

in samples as diverse as ancient pottery shards and 

lake water pollutants . 

The NIST Center for Neutron Research
 
NIST Center for Neutron Research Instruments
 

NIST Center for Neutron Research Instruments 

2 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
 2012 ACCOMPLISHMENTS AND OPPORTUNITIES

(as of Dec. 2012)
 

NIST Center for Neutron Research Instruments
 

3 
NCNR Images 2012
 

NCNR Images 2012
 

Takoma Park (MD) Middle Schoolers jump for joy on their NCNR tour Hao Shen and Doug Godfrin, University of Delaware, take a break for a 

photo-op at NG-3 SANS

NCNR’s Kate Ross at the DCS console listens to comment by former 

advisor Bruce Gaulin, McMaster University

NCNR’s Cedric Gagnon (front) guides University of Maryland researchers 

Hyuntaek Oh and Nick Yaraghi on NG-3 SANS

Zach Levine (NIST Sensor Science Div .) takes a few pointers from 

NCNR SHIP student David Chu

Sachith Dissanayake, University of Virginia, appears pleased with his 

powder diffraction results visible on the High Resolution Powder 

Diffraction instrument display

4 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 2012 ACCOMPLISHMENTS AND OPPORTUNITIES 5 

New guide hall with 10 m SANS being placed Also visible at left are Shingo Maruyama, University of Maryland, records data at the FANS 

enclosed guides NG-D and NG-C instrument console

Andrey Podleznyak, ORNL, at the Neutron Spin Echo instrument console NCNR’s Juscelino Leao works his personal magic with future scientists 

at the NSF booth of the 2012 Science Tech Expo

NCNR’s Michael Dimitriou is just as intrigued as participant TingTing Liu 

about reflectometry results while Marilia Cabral ponders her data at the 

NCNR Summer Workshop

Matt Helgeson (University of California Santa Barbara) with Ph D

student Juntae Kim anticipate excellent rheo-SANS results

(See Helgeson’s article on p . 36) 

NCNR Images 2012
 
Archeology

Foreigners or not: new data prior to the Maya 

collapse in the western lowlands of mesoamerica 

R. Bishop1 and M.J. Blackman1,2 

I

n 1952 Robert Oppenheimer suggested the use of neutron 

activation analysis (NAA) to chemically analyze archaeological 

artifacts as a possible peaceful application of nuclear energy 

under the Atoms for Peace program. The thought was to 

use the chemical composition of artifacts to identify the source 

of raw materials or site of manufacture. By the early 1970s 

instrumental neutron activation (INAA) became, and still is, 

the preferred method for the analysis of archaeological ceramics. 

Among the first archaeological ceramics analyzed by INAA were 

orange fine paste pottery made by the ancient Maya. Today, 

Maya Fine Orange pottery continues to be analyzed, as part of 

collaboration between the NIST Center for Neutron Research 

and the Smithsonian Institution. The data provide a new window 

into the events concerning one of the great mysteries of the past 

— the “collapse” of the lowland Maya civilization in the ninth 


century AD.
 

From approximately 1100 BC to the mid-800s AD a highly 

complex society developed, reaching its apogee in the rain 

forests of southern Mexico, Guatemala, Belize and western 

Honduras. The society’s achievements in art, monumental 

architecture, mathematics—independently inventing the concept 

of zero—, and astronomy rivals other great civilizations of the 

world. Religious and civic administration rested in the hands 

of elite members of the society, headed by a grand lord or king, 

sometimes ruling grand city states, exemplified by such wellvisited archaeological ruins today as Tikal, Calakmul, Palenque 

and Copan (Fig. 1). Hieroglyphic texts tell of kingly succession, 

marriages, alliances, and especially warfare for territorial 

expansion and celebrated in grand public ceremonies. 

By the middle of the eight century AD, beginning with sites 

in the far west, and expanding to those in the upper reaches of 

the great Usumacinta River and in the Central Peten state of 

Guatemala, ties to the civic and ceremonial centers and to the 

grand lords were slipping. By 830 many of the great centers 

had only remnant populations and by 1000 vast areas of the 

Maya lowlands were depopulated—remaining that way until 

recent times. So what happened? Among the more prominent, 

somewhat sensationalistic explanations are ones that involve a 

peasant revolt against the elite, soil exhaustion, drought, disease, 

earthquakes, expansionistic warfare, and foreign invasion. 

FIGURE 1: Map showing major sites in the Maya region and southern 

Veracruz from which pottery has been analyzed using INAA

No single cause however can explain the loss of cohesion of 

the political system and decline of the power of the divine 

lords. Studies of ceramic composition, including sources of 

manufacture and patterns of dispersion, are providing some new 

insights into changes that were taking place. 

FIGURE 2: Left: Maya ceramic; Provincia Plano Relief showing long-haired 

figure Middle: Maya ceramic; Pabellon Modeled-carved . Right: Non-Maya 

Campamento Fine Orange, imported to Cancuén from southern Veracruz

The original use of INAA to characterize Fine Orange pottery 

was directly related to the possibility that foreign invaders were 

involved in the dramatic changes of the late eighth century. 

The construction of buildings ceased, as did the erection of 

monuments, and use of polychrome pottery. It was sometime 

during these changes that a distinctive, orange, finely textured 

ceramic appeared which carried “non-Maya images,” conceivably 

Photo credits: Ronald L. Bishop 

1 Smithsonian National Museum of Natural History, Washington, DC, 20013 

2 NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899 

6 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

from the Southern Veracurz or Tabasco plains to the north: 

the lands of the Putun (Fig. 2 left: Fine Orange with long hair 

image; middle: non-Maya features.) Our long term application 

of NAA to this distinctive ceramic, obtained from national and 

international collections and through recent excavation, has yield 

significant information. 

We have established that the Usumacinta River, which arises in 

the mountains of Guatemala and flows for more than 1000 km 

(600 miles) into the Gulf of Mexico, is the “source” of the Fine 

Orange pottery. With our use of 18 elemental concentrations, 

12 of which are quantified to less than 4 % analytical error, 

we have been able to accurately locate a subregion for Fine 

Orange pottery along this great riverine artery. The locus of early 

manufacture is determined to lie within an approximately 50 km 

zone located between the small modern town of Balancan and 

the archaeological site of Jonuta (see Fig.1). Sedimentary features 

including levees, oxbows and hydrological events including 

annual inundation have sorted the weathered silts and fine sands 

into highly localized resources that are only slightly different but 

can be distinguished use the neutron activation data (Fig. 3). 

FIGURE 3: Plot of Fine Orange ceramic data relative to the concentration 

of chromium and iron to show separation between major Fine Orange 

group and pottery from Southern Veracaruz Groups have formed 

according to similarity using 18 elemental concentrations obtained 

by neutron activation analysis Groups have been refined using their 

Mahalanobis distances from the individual group multivariate centroid

All groups are separate at a 95 % confidence interval

Later, perhaps sometime in the ninth century, makers of Fine 

Orange moved downstream closer to the Usumacinta delta 

region. Whereas the earlier Fine Orange had been moved/traded 

to sites of the interior of the Maya lowlands, the latter pottery 

was circulated to sites along the coast, and around the Yucatan 

Peninsula. This may be a reflection of changing trading habits 

that responded to the movement of western and central Maya 

inhabitants toward the coast. Also in the late eight century there 

appears to be another major producer of Fine Orange that placed 

heavy emphasis on the strange designs found on pottery of the 

earliest analyses (Fig. 2 middle). A subregion for the manufacture 

of that pottery appears to be centered upstream on the 

Usumacinta about the site of Yachixlan. From there, Fine Orange 

was moved to the east and even copied and traded by groups at 

the declining great city of Tikal. 

Recent excavations at the site of Cancuén resulted in a surprising 

find: a Fine Orange vessel (Fig. 2, right) recovered in good 

context under a sealed floor along with a distinctive type of Fine 

Gray ceramics. The problem was the association, namely, that it 

placed Fine Gray and Fine Orange together some 50 years before 

the “collapse” and the time that Fine Orange was to become 

abundant. We analyzed the Fine Orange vessel and several other 

similar ceramic fragments, only to find that it did not match the 

usual paste composition of other Maya Fine Orange ceramics. 

Searching the accumulated database of more than 36,000 

analyses of Maya ceramics we found a match with recent data 

from pottery in Southern Veracruz. The use of neutron activation 

data demonstrated that both the Fine Gray and the Fine Orange 

vessels were not strictly speaking “Maya” but rather has been 

made from the resources in southern Veracruz. The INAA data 

represented contact with people in the southern Veracruz – 

Tabasco plain region in the mid 700s. We revisited our neutron 

activation data base and have been able to identify other ceramics 

from southern Veracruz pottery that were present at several 

other sites along the Usumacinta more toward the interior of 

Guatemala. 

The “strange designs” on the Maya Fine Orange pottery was 

originally thought to be evidence of non-Maya people and 

thereby being threatening to dwellers of the Maya cities or 

perhaps part invasion. However, later study suggested that the 

designs were more or less within “Maya” canons. The chemical 

data has allowed us to determine that there was secure evidence 

of contact between the southern Veracruz and Maya regions, that 

it occurred at several population centers, and it occurred well 

before the major events that precipitated the Maya collapse. The 

designs and personages found on the ceramics coming into the 

core area of the Maya are slightly different because they represent 

a fusion of ideas that came together over at least half a century. 

Sites on the western edge of the Maya area, for example have 

several ceramic traditions that break with other Maya centers and 

reflect strong, influences of people in the Gulf coastal area. 

Rather than considering the southern Veracruz – Tabasco region 

being a home of foreign invaders, we can begin to appreciate that 

it combined with the Western Maya area as an interaction zone 

involving trade in such items as cotton, quetzal feathers, cacao, 

and jade. An interaction zone is quite different conceptually 

than a hostile border between socially different groups. The 

interpretations based on the neutron activation data of fine 

paste pottery are forcing us to re-evaluate the interactions of 

neighboring groups during the decades immediately prior to the 

societal changes that are known as the Maya Collapse. 

Archeology

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 7 
Biology

Walking the line between life and death: membrane


binding and regulation of the PTEN tumor suppressor
 

S. S. Shenoy1, P. Shekhar1, F. Heinrich1,2, H. Nanda1,2, A. Gericke4, M.-C. Daou5, A. H. Ross5 and M. Lösche1,2,3 

I

n recent decades, biology made tremendous progress in 

determining how cells – the smallest viable units that support 

life and form large organisms, such as ourselves – cast critical 

decisions whose outcomes often discriminate death from 

survival. For example, after completing their useful life cycle, 

cells are signaled to “shut off”, so that they can be replaced by 

fresh cells – a process called apoptosis, or controlled cell death. 

If worn-out cells lose their ability to be “shut off” because of 

malfunctions of the underlying cell signaling machinery, they 

transform into cancer cells, i.e., immortalized cells that divide 

beyond control – the start of tumor growth. 

Many cell signaling processes occur on cell membranes – 

nanometer-thin, fluid lipid bilayers and their associated proteins 

that enclose each cell. One such bilayer forms the plasma 

membrane that separates inside from out. Lipid membranes 

are disordered assemblies of their constituent molecules, held 

together by weak intermolecular forces but not through the 

much stronger, and much more inflexible, covalent chemical 

bonds. As a result, membranes respond dynamically to changes 

in their environment, be it within the cell or at the outside. 

However, cell membranes are extremely difficult to characterize 

by physical techniques such as x-ray crystallography, and 

biochemical techniques are often only indirect and nonquantitative. This is where neutron scattering enters the game. 

Our collaboration studied PTEN (short for phosphatase and 

tensin homologue deleted on chromosome 10) [1], a protein that 

plays a key role in the apoptosis cell signaling pathway, and 

its interaction with membranes. PTEN is a tumor suppressor 

[2], i.e., it shifts the balance between life and death for an 

individual cell toward cell clearance. At the plasma membrane 

PTEN finds a specialized signaling molecule, a lipid of the 

phosphoinositolphosphate (PIP) family, which it cleaves in an 

enzymatic reaction [3]. PTEN has been identified as one of the 

most frequently mutated proteins in human tumors [4], i.e., if 

PTEN cannot fulfill its function properly, the result is almost 

always cancer. There is yet little understanding of how the 

tumor suppressor associates with the membrane, finds its target 

substrate and processes it to shift the balance toward cell death. 

Most importantly, it is not clear how the tumor suppressor is 

regulated, i.e., by which physical mechanisms the cell decides 

whether its activity should increase or decrease. 

Recently, a low-resolution structure of PTEN on a bilayer 

using sparsely-tethered bilayer lipid membranes (stBLMs) [5] was 

obtained with neutron reflectometry (NR) [6] (see Fig. 1a). 

The structure shows that the protein associates closely with the 

membrane without penetrating deeply. Although NR on its own 

does not provide sufficient resolution to determine atomic-scale 

details, it characterizes the structure in its biologically relevant 

membrane-bound state, including disordered parts of the protein 

that are invisible in the PTEN crystal structure [7]. A second 

breakthrough came by combining the NR results with molecular 

dynamics (MD) simulations of the membrane-bound protein 

and of the protein in solution. Without any cross-reference to 

the experimental results, the membrane-bound MD simulations 

settled exactly into the NR structure (see Fig. 1b). This is 

strong evidence that both the NR and the MD simulations 

independently describe the structure correctly at their different 

levels of resolution. 

NR and MD simulations in combination unlock a wealth 

of previously inaccessible information (see Fig. 2). The MD 

simulations of the membrane-bound PTEN show that two 

distinct regions of the protein, located at the phosphatase (PD) 

and the C2 domain, tie the protein peripherally to the membrane 

surface. In between the two contact points and buried within the 

PD, is the catalytic site, which cleaves the headgroup of a specific 

PIP lipid, thus shifting the regulatory chemical circuit toward 

cell death. A comparison between the solution structure and the 

membrane-bound structure of the protein shows that both are 

slightly distinct and in turn different from the crystal structure. 

In the membrane-bound state, the PD is rearranged, such that 

the body of the PTEN protein flattens somewhat against the 

bilayer surface, thus gaining easier access to its substrate. 

The most significant difference between the membrane-bound 

and solution states of the PTEN protein, however, concerns 

the disordered C-terminal tail. Because of anionic charges 

1 Department of Physics; Carnegie Mellon University; Pittsburgh, PA 15213 

2 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg, MD 20899 

3 Department of Biomedical Engineering; Carnegie Mellon University; Pittsburgh, PA 15213 

4 Worcester Polytechnic Institute; Worcester, MA 01609 

5 University of Massachusetts Medical School; Worcester, MA 01605 

N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 8 
FIGURE 1: The low-resolution structure of the membrane-bound 

PTEN phosphatase as a neutron scattering length density (nSLD) 

distribution across the membrane . The bilayer, only partially shown, 

extends to the left . The high nSLD around d = – 10 Å shows the 

lipid headgroups . Experimentally determined nSLD (red) and its 

interpretation (a) by accommodating the crystal structure of a 

truncated PTEN variant [7] and (b) from MD simulations of the fulllength protein . Shaded blue band indicates the confidence intervals 

around the best-fit model (red line) . The image in (a) shows a 

structural model represented by this nSLD profile [6] . 

along the peptide chain, the tail is repelled by the anionic 

membrane surface in the membrane-bound state of the protein. 

In contrast, in solution this tail wraps around the C2 domain 

where it partially obstructs the membrane-binding interface. This 

conformation could be locked in place if the C-terminal tail itself 

becomes phosphorylated, a chemical modification that has been 

reported to interfere with the membrane binding of the protein [8]. 

A detailed view of the duty cycle of PTEN, a key regulator in 

the cell signaling pathway that controls apoptosis, has been 

uncovered using neutron scattering techniques and MD 

simulations. For the first time, this provides a high-resolution 

structure of a supra-molecular complex comprised of a 

disordered lipid membrane and a peripherally associated protein. 

Functionally important disordered parts of the protein were 

determined in their distinct organization on and off the 

membrane, and it became clear that the crystal structure is 

neither an entirely appropriate description of the solution 

structure nor the membrane-bound structure of PTEN. Thus, 

atomic-scale details become available which are crucial for 

in-depth understanding of the fine line that separates life 

from death. 

References 

[1] J. Li, et al., Science 275, 1943 (1997). 

[2] N. R. Leslie and C. P. Downes, Biochem. J. 382, 1 (2004). 

[3] F. Vazquez, et al., Proc. Natl. Acad. Sci. USA 103, 3633 (2006). 

[4] L. Simpson and R. Parsons, Exp. Cell Res. 264, 29 (2001). 

[5] D. J. McGillivray, et al., Biointerphases 2, 21 (2007). 

[6] S. Shenoy, et al., PLoS ONE 7, e32591 (2012). 

[7] J. O. Lee, et al., Cell 99, 323 (1999). 

[8] F. Vazquez, et al., Mol. Cell. Biol. 20, 5010 (2000). 

Biology

FIGURE 2: MD simulations of PTEN on a membrane (a) and in 

solution (b) . The inset in panel (a) shows the interaction of amino acid 

sidechains with lipids . The two core domains, C2 and PD, organize 

similarly in solution and on the bilayer, where the protein is slightly 

more flattened against the membrane surface . At the membrane, the 

flexible C-terminal tail (red), is electrostatically repelled by the anionic 

bilayer . In distinction, it wraps around C2 in solution and obstructs 

the membrane binding interface (left in panel b) . In the rotated view 

(right), amino acid side chains are highlighted that may play a role in 

controlling PTEN’s membrane association . 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 9 
 

 

 

Biology

Towards the elucidation of antiboitic resistance 

transfer in bacteria: structural studies of the 

TraI protein 

N.T. Wright1, M. Raththagala2, E. Bruenger2, J. Schildbach2, J.E. Curtis3 and S. Krueger3 

Approximately 70 % of bacteria responsible for 

hospital-acquired infections are resistant to at 

least one antibiotic commonly used to treat the 

infection, which presents a serious public health 

problem. Bacterial conjugation, or lateral gene transfer, plays 

an important role in the spread of genes, leading to increased 

abundance of pathogenic or antibiotic-resistant bacteria. 

The mechanism of bacterial conjugation can be elucidated 

by understanding the regulation of its components. 

One component, TraI, is a protein that is essential for 

the unilateral transfer of DNA from donor to recipient 

bacterium. In order to pass through the conjugative pore, 

TraI likely unfolds, at least partially, prior to transfer, though 

the mechanism and extent of unfolding is unknown. We are 

interetested in studying the orientation of the domains in 

combination with large-scale structural changes of TraI that 

are the responsible for the regulation of TraI functionality and 

hence the transfer of antibiotic resistance. In this report we 

have combined high-resolution nuclear magnetic resonance 

spectroscopy (NMR) and small-angle neutron scattering 

(SANS) to screen models in order to elucidate the structure 

of portions of the TraI protein. 

TraI is a 1,756 residue protein containing several functional 

domains. The functional domains of TraI include: a 

N-terminal nickase domain that binds and nicks (cleaves one 

strand of ) plasmid DNA at the origin of transfer (oriT); a 

non-specific single-stranded DNA (ssDNA) binding domain; 

a helicase domain; and a C-terminal domain. A schematic 

of the domain structure of TraI is shown in Fig. 1. While 

structures have been solved for several domain fragments, 

there is currently no high-resolution structural data available 

for the full-length TraI protein. Obtaining structural 

information is necessary for determining how conformation 

regulates TraI function during DNA transfer. 

FIGURE 1: Schematic of TraI protein Regions of known structure are 

colored in red, blue (current report), and orange . TS1 and TS2 stand for 

Translocation Sequences 1 and 2, which are regions containing sequences 

necessary for protein transfer to the recipient cell Walker A/B identifies 

the ATP binding site in the helicase domain Hash marks indicate no 

currently known structure or function

We combined structural data from NMR and SANS 

measurements. Structural models were developed using both 

molecular dynamics and molecular Monte Carlo simulations. 

Models were screened by comparing synthetic SANS profiles 

to experimental data. In the first part of the study we 

determined the structures of the residues 306-381. In the 

second part we studied a larger fragment of TraI composed 

of residues 1-569. Small-angle neutron scattering 

experiments were performed on the 30 m SANS instruments 

at the NCNR. 

TraI model structures were generated by combining known 

x-ray and NMR structures along with molecular dynamics 

simulations. Molecular Monte Carlo simulations were 

performed using the program SASSIE [2] where intrinsically 

disordered regions were permitted to sample allowed 

conformational space. Model SANS profiles corresponding to 

each of these model structures were calculated using Xtal2sas. 

Chi squared analysis and protein density map calculations 

were generated using SASSIE. In Fig. 2, we show an ensemble 

of structures obtained by combining analysis of NMR and 

SANS data for residues 306-381 of TraI combined with the 

known x-ray structure of residues 1-305. This result indicates 

that residues 306-381 are only paritially disordered and the 

region is slightly compact. We extended our analysis to study 

residues 1-569 of TraI as shown in Fig. 3. We find through 

analysis of small-angle scattering data that two domains that 

are known to exhibit negative cooperativity to binding DNA 

are found to be adjacent in three dimensional space. 

1 James Madison University; Harrisonburg, Virginia 22807 

2 Johns Hopkins University; Baltimore, MD 21218 

3 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg, MD 20899-8562 

10 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

 

 

 

 FIGURE 2: Structure of the first TraI linking region (306 to 381) (a) NMR 

spectra overlay between F-TraI (381-569) in black and F-TraI (309-569) 

in red The red spots suggests that part of this construct is well-folded 

(mostly, those whose peaks overlay with (381-569)), while part of this 

construct is poorly folded or unfolded (b) shows a composite image 

arising from SANS data collected on TraI (1-330) . Residues 1 to 305 of the 

modified 1P4D crystal structure are represented in red Using the program 

SASSIE [2], 5795 structures were generated by Monte Carlo sampling 

the backbone dihedral angles for residues 306 to 330 The protein shell 

of residue 306 to 330 from this simulation is represented in black mesh

The SANS profiles of these structures were then back-calculated and 

compared to actual SANS data of TraI (1-330) The protein shell of residues 

306 to 330 from those models that most closely agreed to the actual SANS 

data (χ2

 < 5) is represented in green . This shows that residue 306 to 330 

does not exist in a well-formed structure in this construct

In summary we have determined the solution structures of 

the N-terminal fragment of the F TraI helicase-associated 

ssDNA binding domain. We determined that this structure 

forms a well-folded globular motif consisting of a core of 

four parallel b strands that are surrounded by helices. We 

also determined how this region of TraI is situated in the 

context of the entire N-terminal third of the TraI molecule. 

3525 45 55 65 75 

R (Å) g 

100 

200 

300 

0 

χ 2 

(a) 

(b) 

(c) 

Biology

FIGURE 3: Orientation of domains within TraI (1-569) 8755 models 

of TraI (1-569)-oriT, ssDNA, and small-angle scattering profiles were 

generated using SASSIE, where residues 306 to 389 were allowed to 

randomly move (a) A plot of the χ2

 versus radius of gyration . Data 

colored in blue represent those models with a χ2

 value of less than 15 . (b) 

TraI (1-305) is shown in red, with the protein shell of residues 306 to 569 of 

all models represented in black mesh Those models with a low χ2

 value 

(240 models) are depicted in blue . (c) shows the model that most closely 

agrees with the scattering data In this and all other well-agreeing models, 

the nickase (red) and (390-569) (blue) are close to each other in physical 

space In green is the 12 bp ssDNA from the crystal structure of nickasessDNA, which is the fragment that was bound to the nickase domain in 

these experiments

Although TraI is a modular protein, the nickase and ssDNA 

binding domains are in close proximity to each other, 

and are apparently oriented not through direct domaindomain interaction but instead through the partial folding 

of a linker region. This orientation of domains may have 

functional consequences, in that it gives the apparent negative 

cooperativity of ssDNA binding a structural basis. 

References 

[1] N.T. Wright, M. Raththagala, C.W. Hemmis, S. Edwards, J.E. 

Curtis, S. Krueger, and J.F. Schildbach, Proteins: Struc., Funct., 

Bioinf. 80, 2250 (2012). 

[2] J.E. Curtis, S. Raghunandan, H. Nanda, and S. Krueger, 

Comp. Phys. Comm. 183, 382 (2012). 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 11 
Biology

Structures and conformations of voltage-sensor 


domains and voltage-gated K+ channel proteins
 

S. Gupta1, J.A. Dura2, D.L. Worcester2,3,5, J.A. Freites4, D.J. Tobias4 and J.K. Blasie1 

I

on channel proteins control the diffusion of ions such as 

K+1. Na+1 and Ca+2 across plasma membrane of cells, thereby 

affecting numerous cellular signaling processes, especially 

those involving the electrochemical potential across the 

membrane, called the membrane potential. These ion channels 

change conformations from one structure to another (within 

a few milliseconds) in order to open or close the channel in 

response to stimuli. Important channels which are responsive to 

changes in membrane potential are the voltage-gated potassium 

(Kv) and sodium (Nav) channels which have fundamental roles 

in propagating action potentials along nerve axons, thereby 

providing nerve cell signaling in all animals. These channels 

are also sites for effects of both general and local anesthetics. In 

addition to open and closed conformations, some ion channels 

have an inactivated conformation, which ensures that the 

electrical signals propagate in only one direction along a nerve 

axon. Details of these different conformations and the switching 

between them are crucial to understanding the function of 

voltage-gated ion channels. 

Voltage-gated ion channel proteins are large structures with 

domains that perform distinct roles, such as the channel pore 

containing the selectivity filter, generally four voltage sensor 

domains (VSD), and an inactivation gate to block the pore. 

Channel responses to changes in membrane potential require 

electromechanical coupling between VSDs and the pore domain 

(PD), the mechanism of which remains unknown. X-ray crystal 

structures of a few voltage-gated potassium (Kv) channels and a 

voltage-gate sodium (Nav) channel have been determined and 

provide much basic structural information, but these pertain 

to only the open state. Furthermore, the channel proteins in 

these crystals are in a non-native environment since there is no 

lipid bilayer. The importance of lipids was demonstrated by 

experiments showing that without certain lipids (phospholipids) 

the channels do not function. 

In the present work, methods have been developed to obtain 

structural and conformational information on channel proteins 

all oriented in the same direction, and their separate domains 

in phospholipid membrane environments similar to nerve cells. 

These methods include the possibility of applying membrane 

potentials and monitoring protein conformational changes in 

response to changes in the potential. Neutron reflectometry is 

utilized to characterize the membrane protein conformation in 

detail at the sub-molecular level using a single membrane that 

contains oriented channels, tethered to a special substrate [1]. 

The use of neutron reflectometry has inherent advantages arising 

from solvent contrast variation (H2O/D2O) coupled with the 

deuteration of selected membrane molecular or sub-molecular 

components, especially important for the solid/liquid interface. 

A new approach is used to form the tethered membrane. 

Instead of forming a lipid bilayer tethered to the substrate, 

the protein channels themselves are tethered to the substrate 

and phospholipids, such as 1-palmitoyl-2-oleoyl-sn-glycero-3­

phosphocholine, (POPC) are added to form the bilayer, with 

the lipid bilayer attaining its equilibrium location with respect 

to the tethered protein. By tethering the whole protein, or a 

protein domain of interest, to the substrate, its orientation with 

respect to the substrate is assured. Therefore it is possible to more 

accurately determine its unique location and conformation in 

SLD profiles. This is an advantage over other techniques that 

lose information by averaging over the two possible orientations 

of the protein across the membrane [2]. To achieve protein 

tethering, the proteins of interest are expressed with a modified 

carboxyl terminus that has six histidine residues added. These 

provide linking to an alkylated substrate by co-ordination 

chemistry. 

Another essential technique is to utilize a known reference 

multilayer of high scattering length density (SLD) in the 

substrate to enhance features of the reflectivity by neutron 

interferometry. The reference multilayer also provides a marker 

of the position of the membrane with respect to the substrate 

surface and can be used to “phase” the reflectivity data. As 

a result, unique SLD profiles can be derived whose spatial 

resolution (minimum wavelength Fourier component) is limited 

by the accessible Qz-range. These resolution-limited SLD profiles 

can be modeled with error functions. Such modeling effectively 

fits both the modulus and phase of the reflectivity data, unlike 

the more traditional refinement of such “slab-models” which 

utilize only the modulus data. 

Omitting details [1] for brevity, we present only the errorfunction, or “slab-models” of the experimental SLD profiles 

1 University of Pennsylvania, Philadelphia, PA 19104 

2 NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 

3 Dept . of Physiology & Biophysics, University of California, Irvine, CA 92697 

4 Dept . of Chemistry, University of California, Irvine, CA 92697 

5 University of Missouri, Columbia MO 65201 . 

12 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
derived by phasing the reflectivity data. Figure 1 (top) shows the 

profile structure of the precursor, tethered VSD:OG monolayer 

(i.e., VSD solvated by a detergent, n-octyl-β-D-glucopyranoside 

(OG)), fully hydrated with bulk aqueous media for 100 % D2O 

(blue) and (60 % D2O)/(40 % H2O) (green). The water slabs at 

either surface of the membrane are removed to reveal the VSD 

itself. Figure 1 (middle) shows the profile structure of the 

POPC bilayers within the reconstituted VSD:POPC membrane 

fully hydrated with bulk aqueous media for (60 % D2O)/ 

(40 % H2O) for D4-POPC (blue) vs. H-POPC (red). The 

former contains four deuterium atoms within the phospholipid’s 

polar head group. The differences in the slab-model profiles, here 

due to hydration with bulk H2O or D2O (top) and D4-POPC 

or H-POPC (middle), are statistically significant, exceeding the 

propagated experimental error. Figure 1 (bottom) shows the H-D 

exchange profile for the reconstituted VSD:POPC membrane 

(blue) , and for the VSD (red) itself within the membrane. This is 

in good agreement with that predicted by a molecular dynamics 

simulation. A cut-away view of the simulation system (Fig. 1 

bottom inset) shows that when the VSD is embedded in a lipid 

bilayer, water molecules penetrate throughout the VSD profile 

via a “pore” forming an internal hydrogen bond network with a 

set of highly-conserved basic and acidic side chains. 

FIGURE 1: Summary of the slab-model profiles as described in the text . The 

inset is from a MD simulation where the voltage-sensitive domain is shown in 

ribbon (orange) representation, the lipid bilayer has been deleted for clarity, 

and waters are colored by atom (oxygen, red; hydrogen, white) . 

These results are in much greater sub-molecular detail than 

previously achieved. They demonstrate the unidirectional 

orientation of the VSD and the retention of its molecular 

conformation (secondary and folded 3-D tertiary structure) 

manifest in the asymmetric profile of the protein within this 

reconstituted single bilayer membrane system. They describe the 

structure of the phospholipid bilayer solvating the lateral surfaces 

of the VSD protein. The profile structures of both the VSD 

protein and the phospholipid bilayer also demonstrate significant 

dependence on the hydration state of the membrane (not 

shown). They also provide the distribution of hydration water 

and exchangeable hydrogen throughout the profile structure of 

both VSD itself and the VSD:POPC membrane for the fully 

hydrated case. The two experimentally determined water and 

exchangeable hydrogen distribution profiles are consistent with 

the existence of a water pore within the core of the VSD, as first 

indicated by MD simulations. 

The structural detail obtained is derived not only from neutron 

interferometry coupled with solvent contrast variation and 

selective deuteration in the polar headgroup of the POPC 

component, but also because of the unidirectionality of the VSD 

protein within the membrane. Such results cannot be achieved 

utilizing more typical membrane reconstitution approaches that 

generally result in an average orientation of the protein with 

equally populated opposed directions. This average orientation 

results in the determined profile structures of both the protein 

and the phospholipid being symmetric about the center of the 

membrane profile structure. 

Some results (not shown) were obtained for the full-length KvAP 

protein for both the tethered KvAP:DM monolayer and the 

subsequently reconstituted KvPA:POPC membrane. While these 

results are not as extensive as those described for the VSD, they 

demonstrate a successful reconstitution of a phospholipid bilayer 

environment for the unidirectional KvAP protein, more similar to 

that of a pure phospholipid bilayer than that for only the VSD itself. 

This work on unidirectional channel proteins in lipid bilayers 

provides a basis for the investigation of the profile structures as a 

function of the applied transmembrane voltage. In such studies, 

the substrate to which the reconstituted membrane is tethered 

also serves as the working electrode in the electrochemical cell. 

Neutrons can easily penetrate the solid/liquid materials forming 

the cell, but the relatively low incident neutron flux will likely 

limit such studies to profile structures at steady-state values of 

the potential. High-energy ( > 20 keV) x-rays are required to 

penetrate solid/liquid materials complicating the cell design, but 

the much higher incident photon flux provided by synchrotron 

radiation sources can allow time-resolution of the response of the 

profile structure to a step-wise change in the potential. 

References 

[1] S. Gupta, J.A. Dura, J.A. Freites, D.J. Tobias, and J.K. Blasie, 

Langmuir 28, 10504 (2012). 

[2] D. Krepkiy, M. Mihailescu, J.A. Freites, E.V. Schow, D.L. 

Worcester, K. Gawrisch, D.J. Tobias, S.H. White and K. Swartz, 

Nature 462, 473 (2009). 

Biology

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 13 
 

Biology

The role of electrostatic interactions in the local 

dynamics of biological and synthetic polyelectrolytes 

J.H Roh1,2, M. Tyagi2,3, R.M. Briber2, S.A. Woodson4, A.P. Sokolov5,6 

RNA is the only known biomolecule capable of both 

self-replication and enzymatic activity. Recent research 

has shown that there is a broad diversity of classes of 

RNA molecules, the knowledge of which is leading to 

advances in the understanding of basic biochemical processes in 

the cell and which holds significant promise for biotechnology 

applications. Understanding conformational dynamics of RNA is 

critical for mapping out the microscopic mechanism of biological 

events such as self-assembly, folding, ligand recognition and 

catalysis [1]. RNA folds to the compact native state in presence 

of Mg2+ ions which screen the negative charges on the RNA 

backbone arising from the phosphate groups. Folding allows 

for the formation of long-range tertiary interactions and 

results in a concomitant decrease in the radius of gyration and 

stabilization of the native state. In this work we describe our 

recent quasielastic neutron scattering studies using the HFBS 

instrument to examine the effect of Mg2+ counterions on the 

picosecond to nanosecond local dynamics and structure of 

hydrated tRNA in comparison to sulfonated polystyrene (SPS) 

[2]. This work provides insight into the role of electrostatic 

interactions on the dynamical fluctuations and structural 

stabilization of RNA and synthetic polyelectrolytes. 

Figure 1a exhibits the dynamic transition (Td) which is associated 

with the onset of anharmonic motion and which appears in both 

unfolded (u-) and folded (f-) tRNA between T ≈ 180 K and 

200 K. Another transition occurs at T ≈ 325 K and is associated 

with the melting of secondary (2o

) and tertiary (3o) structures. 

Interestingly, the mean squared displacement, <r2>, values for the 

more compact f-tRNA were observed to be greater than those 

for the more extended u-tRNA at all temperatures up to 350 K. 

The more rapid change of <r2> in f-tRNA between 200 K and 

250 K implies that the observed dynamics are not controlled 

solely by the hydrating water, but are significantly affected by the 

electrostatic nature of the RNA surface. 

To separate how Mg2+ influences the flexibility of tRNA 

through stabilization of the tertiary structure and by altering 

the electrostatic environment, we also characterized the 

dynamical flexibility SPS with and without Mg2+. As a synthetic 

polyelectrolyte, SPS does not have the tertiary interactions which 

are present in RNA. Like f-tRNA, SPS screened by Mg2+ 

FIGURE 1: Temperature dependence of the mean-squared 

displacement, <r

2

(T)>, obtained from a Gaussian approximation, 

<r

2

(T)> = -3Q-2 ln[Iel(Q,T )/Iel(Q,50 K)] for Q between 0 .25 Å-1and 1 .00 

Å-1 . (a) Powder unfolded (u-) and folded (f-) tRNA samples were 

hydrated to 42 % mass fraction corresponding to completion of the 

first hydration layer . The dynamic transition (Td ≈ 200 K) and melting 

transition ( TΔ

2°3° ≈ 325 K) are indicated . (b) D2

O solutions of u- and 

f-tRNA and unscreened (unsc-) and screened (sc-) SPS . 

(sc-SPS) showed larger local motion compared to unscreened SPS 

(unsc-SPS) (Fig. 1b). The larger <r2> values of sc-SPS and f-tRNA 

indicate that the Mg2+ induced electrostatic neutralization leads 

to larger and more thermal fluctuations of the polyelectrolyte. It is 

striking that <r2> of biological RNA and a synthetic polyelectrolyte, 

SPS, increase similarly with temperature, in both the unscreened 

and Mg2+ screened conditions. 

Because the materials in this study have similar hydration levels, 

the differences we observe are primarily due to Mg2+. Together 

with our earlier results [2], this suggests that the dynamical 

properties of both biological and synthetic polyelectrolytes are 

mainly controlled by solvation and electrostatics, rather than by 

specific macromolecular structure. 

To understand the details of the dynamics, we analyzed the 

dynamic structure factor, S(Q,E), of hydrated unfolded and 

folded tRNA powder at different temperatures. The total 

scattering spectra can be represented as: 

S(Q,E) = DW(Q)[(1-QISF(Q))δ(E) + QISF(Q)SQENS(Q,E)]⊗R(E) (1). 

Here DW(Q) is the Debye-Waller factor, QISF(Q) is the 

quasielastic incoherent scattering factor defined as the ratio of 

quasielastic scattering to the total scattering intensity, SQENS(Q,E) 

is the quasielastic scattering function, and R(E) is a resolution 

function. The amplitude of QISF is directly proportional to the 

mobile fraction of hydrogen atoms associated with the relaxation. 

1 Naval Research Laboratory; Washington, DC 20375 

2 University of Maryland; College Park, MD 20742 

3 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg, MD 20899 

4 Johns Hopkins University; Baltimore, MD 21218 

5 Oak Ridge National Laboratory; Oak Ridge, TN 37831 

6 University of Tennessee; Knoxville, TN 37996 

14 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

Biology

FIGURE 2: Dynamic structure factor, S(Q=0 56 Å-1 ,E), of u- and f-tRNA at 

various temperatures in (a) and (b) . Resolution functions are S(Q=0 56 

Å-1 ,E) at 10 K . Dashed lines are representative Lorentzian fits of quasielastic 

scattering of f-tRNA at 260 K and u-tRNA at 300 K . (c) Averaged relaxation 

time, <τR>, was estimated from the half-width at half-maximum of a 

Lorentzian peak . No significant Q-dependence of the <τR> values was 

found, indicating that the relaxation is localized (d) Quasielastic incoherent 

scattering factor as obtained from analysis of the peaks

Figure 2a and 2b show that S(Q,E) exhibits about a factor of two 

larger quasielastic scattering from f-tRNA than u-tRNA from 

260 K to 320 K over the given energy range. This indicates that 

f-tRNA experiences a larger mobile fraction with faster local 

motions. The quasielastic scattering of u-tRNA at 350 K becomes 

similar in magnitude to that of f-tRNA at 300 K, which agrees 

with the sharp increase in <r2

> for u-tRNA between 325 and 350 

K as the secondary structure begins to melt. 

The characteristic relaxation time, <τR>, of the tRNA 

motion was estimated from the half-width at half-maximum 

of SQENS(Q,E). Although a single Lorentzian fit is not the 

best analysis for a stretched relaxation spectra, a qualitative 

comparison of <τR> values within the limit of the given time 

window is reasonable, especially for RNA which lacks methyl 

groups (as compared to proteins). The relaxation time of u-tRNA 

is slower and more temperature-dependent than <τR> of f-tRNA 

(Fig. 2c). The average relaxation rate of u-tRNA becomes 

about one order of magnitude slower than that of f-tRNA at 

T ≈ 260 K. Likewise, the QISF of u-tRNA is also lower than that 

of f-tRNA, suggesting the local relaxation is more suppressed 

(Fig. 2d). This suggests that, u- and f-tRNA explore different 

dynamical pathways. These results indicate that water likely 

serves as a plasticizer that lubricates the local motion of the 

hydrophilic macromolecules. 

It has been observed that the compact folded yeast f-tRNAphe 

(Rg ≈ 20 Å for f-tRNAphe) having long-range tertiary interactions 

shows greater dynamical flexibility than unfolded extended yeast 

RNA (Rg ≈ 30 Å for u-tRNAphe) [3]. This result is opposite to the 

relationship between structural compactness and global dynamics 

observed for folded proteins which have been shown to be more 

rigid than denatured proteins. The estimate of the persistence 

length, lp, obtained from solution small-angle x-ray scattering 

(Fig. 3) shows that lp is 1.7 times larger for u-tRNA compared to 

FIGURE 3: Analysis of pair distance distribution functions, P(r), of unfolded 

and folded tRNAPhe . P(r) was obtained from indirect inverse Fourier 

transform of small-angle x-ray scattering intensity using GNOM program 

[3] The radius of gyration, Rg, and persistence length, lp, were estimated 

from P(r) Black lines are the fit of P(r) to the exponential equation at r > Rg 

on the basis of a worm-like chain model [4]

that of f-tRNA (8.4 Å vs. 4.9 Å), indicating significantly higher 

flexibility for the folded tRNA [2]. The difference in persistence 

length is in good agreement with the difference in <r2> between 

f- and u-tRNA at T = 300 K (Fig. 1a). 

Our study demonstrates that charge screening by counterions 

greatly increases the local motion of tRNA and a synthetic 

polyelectrolyte. The increase in the magnitude of the 

displacement, relaxation rate and fraction of mobile atoms is 

consistent with the shorter persistence length of the folded 

tRNA. However, the mechanism by which Mg2+ increases the 

flexibility of coupled dynamics between the compact folded 

tRNA and hydrating water remains unclear. Possible reasons 

include 1) increased electrostatic fluctuations caused by the 

diffusion of hydrated cations and 2) increased fluctuations of 

the hydrogen bond network. Interestingly, NMR, birefringence, 

and molecular dynamics simulation studies reported that 

divalent cations suppress the mobility of single-stranded RNA 

segments, compared to monovalent cations. More details about 

the electrostatic origins controlling hydrating water-coupled 

tRNA dynamics will be developed through the comparison of the 

dynamics in the presence of monovalent cations with different 

ionic densities, such as Na+ and K+ . 

References 

[1] D.E. Draper, D. Grilley, A.M. Soto, Annu. Rev. Biophys. Biomol. 

Struct. 34, 221 (2005); S.A. Woodson, Curr. Opin. Chem. Biol. 9, 

104 (2005). 

[2] J.H. Roh, M. Tyagi, R.M. Briber, S.A. Woodson, A. . Sokolov, J. 

Am. Chem. Soc. 133, 16406 (2011). 

[3] X.W. Fang, K. Littrell, X. Yang, S.J. Henderson, S. Siefert, P. 

Thiyagarajan, T. Pan, T.R. Sosnick, Biochemistry, 39, 11107 

(2000). 

[4] G. Caliskan, C. Hyeon, U. Perez-Salas, R.M. Briber, S.A. 

Woodson, D. Thirumalai, Phys. Rev. Lett. 95, 268301-1 (2005). 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 15 
Chemical Physics
 

Powder neutron diffraction reveals new CO2 

adsorption interactions in chabazite zeolites 

M.R. Hudson1,2, W.L. Queen1, J.A. Mason3, D.W. Fickel4, R.F. Lobo4, and C.M. Brown1,5 

One of the most pressing issues facing the energy 

sector is the mitigation of global warming-implicated 

greenhouse gases through pre- and post-combustion 

capture applications. The efficient and selective capture 

of CO2 from industrial flue gas streams is of particular interest. 

The current strategy, involving absorption in alkanolamine 

solutions, has several disadvantages, namely a lack of corrosion 

control and significant energy requirements for regeneration [1]. 

Typical flue gas streams have N2:H2O:CO2 mass ratios of 6.5:1:1 

and up to 15 % CO2 volume fraction at atmospheric pressure. 

The high gas flow rates make porous materials, such as zeolites, 

promising options for separation/sequestration of CO2. These 

framework materials exhibit high internal surface areas allowing 

them to physically adsorb large amounts of gas. Neutron powder 

diffraction (NPD) is a useful tool for studying these materials [2]. 

Here, we highlight our recent investigation of low-pressure CO2/ 

N2 sorption in the acidic (H-SSZ-13) and copper-exchanged 

(Cu-SSZ-13) derivatives of zeolite SSZ-13 utilizing NPD 

combined with in situ CO2 and N2 adsorption [3]. 

Cu-SSZ-13 is unique among copper-exchanged zeolites in that 

there is only one location for the copper cation in the host 

framework at high silicon/aluminum ratios, thereby simplifying 

the discussion of cation-exchange effects on the uptake and 

selectivity. Additionally, Cu-SSZ-13 has shown improved 

hydrothermal stability over other copper-exchanged zeolites, 

an important property for post-combustion capture of CO2 

in flue streams with the presence of water [4]. The CO2 and 

N2 adsorption data for both H-SSZ-13 and Cu-SSZ-13 were 

collected at 298 K, and the maximum uptake at 1 bar is lower for 

the Cu2+ exchanged derivative: 3.75 mmol/g, compared to the 

acidic form: 3.98 mmol/g. In terms of the number of moles of 

CO2 adsorbed at STP, H-SSZ-13 and Cu-SSZ-13 are in-line with 

the best sorbents for CO2 uptake, and only significantly bested by 

Mg-MOF-74 (5.4 mmol/g at 0.1 bar) [5]. Adsorption selectivities 

for CO2 over N2 were estimated using Ideal Adsorbed Solution 

Theory (IAST) for an idealized flue gas mixture composed of 0.15 

bar CO2 and 0.75 bar N2, to be 72.0 and 73.6 for Cu-SSZ-13 

and H-SSZ-13, respectively [3]. Gas uptake measurements 

indicate that the low-pressure CO2 capacity and IAST selectivity 

relative to N2 are not significantly impacted upon exchanging 

Cu−cations into the host SSZ-13 framework. We have further 

determined the key structural features of the host framework that 

result in the high uptake and selectivity. 

SSZ-13 is composed of corner-sharing Al/SiO4 tetrahedra that 

form double six-membered ring cages (see inset, Fig. 1). The 

cages are further connected to form a cavity with 8-membered 

windows (consisting of 8 O and 8 Si/Al) approximately 

3.8 Å across, providing size-exclusion in the adsorption of 

gas molecules. Based on the potential bond distances and 

coordination, there are four suitable sites for Cu2+. The 6-ring 

window has been determined to be the only copper location 

in Cu-SSZ-13 (SiO2/Al2O3 = 12) from NPD with a refined 

occupancy of 25 % Cu2+, as indicated by nuclear scattering 

density only in this region (Fig. 1). Rietveld refinement of 

NPD data obtained on the bare Cu-SSZ-13 reveals a Cu-O(1) 

distance of 2.24(1) Å to the three coordinate oxygen atoms. The 

potential of a second copper site at higher Cu2+ loadings than 

that presented here has been suggested from TPR and FTIR 

spectroscopy [6]. 

FIGURE 1: Representative NPD Rietveld refinement of the in situ gas 

loaded zeolite at a loading of 0 5 CO2 per Cu2+ at 4 K (final goodness-of-fit 

χ2

 = 1 048) . 

NPD data were further collected at sequential, in situ loadings of 

0.5, 0.75, 1.0, 1.5, and 4.0 CO2

 molecules per Cu2+ cation [3]. 

Fourier difference maps allowed elucidation of CO2 site positions 

and Rietveld refinements provided a final determination of 

atomic coordinates and CO2 occupancy as a function of gas 

loading. At low CO2 loadings there is preferential occupancy of 

the gas molecules at a single site (Site A) located in the center 

of the 8-ring window (Fig. 2). The CO2 carbon is centered in 

the window such that Oring–(C)–Oring angle is equal to 180°. The 

closest CO2

-framework interactions include carbon to Oframework 

1 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg, MD 20899-6102 

2 University of Maryland; College Park, MD 20742 

3 University of California; Berkeley, CA 94720 

4 University of Delaware; Newark, DE 19716 

5 The Bragg Institute; Australian Nuclear Science and Technology Organisation; PMB1 Menai, NSW, Australia 

16 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

FIGURE 2: CO2 adsorption at Site A (left, with oxygen labeling scheme) 

and N2 adsorption site (right) as determined from NPD measurements 

of Cu-SSZ-13 at 4 K (yellow = oxygens; black = carbons; pale blue = nitrogens) for one complete cage The positions of CO2 and N2 relative to 

the 8-ring cage windows are shown as a space-filling representation It 

should be noted that figure represents only the adsorption sites and does 

not quantify the amounts of gas at each location; the actual occupancy is 

much greater for CO2 . 

between approximately 3.2 Å to 3.5 Å. The CO2 molecules, 

which are canted with respect to the c-axis, point towards the 

center of the small pore and away from the secondary adsorption 

site (Site B). Site B has end-on CO2 coordination to the Cu2+ 

with Cu2+...O=C=O equal to 2.69(3) Å (at a 4.0 CO2 per Cu2+ 

loading, Fig. 3). The observed canting angle allows the largest 

possible degree of separation between the CO2 and framework 

oxygen atoms minimizing repulsive interactions between the 

framework and adsorbate. The O-O distances found between the 

ring window and CO2 range from ≈ 3.4 Å to 3.8 Å for Oframework 

to OCO2. The isotropic atomic displacement parameters (ADP) 

for CO2 increase as the occupancy of the CO2 in the window 

increases, which is likely indicative of some static disorder with 

higher loadings. Increasing the gas concentration from 0.5 to 

1.5 CO2 per Cu2+, increases the concentration of CO2 in the 

window, but reveals no evidence of any nuclear density directly 

above the Cu2+, indicating that the window site is the preferred 

adsorption site. NPD of CO2 in H-SSZ-13 loaded with 2.0 

CO2 per H+

 (equivalent to ≈ 3.0 CO2 per Cu2+) also results 

in CO2 adsorption at the window site and is canted similarly 

into the pore. This type of CO2–framework interaction is novel 

compared to that observed in other zeolites, such as cationexchanged Y-zeolite, which have end-on CO2 interacting with 

the cations, or NaX and H/Na-ZSM-5 where CO2 molecules 

form carbonate-like species with framework oxygen atoms [3]. 

To determine specifics of the separation properties, we performed 

additional in situ N2 diffraction for a loading of 1.5 N2 per 

Cu2+ [3]. The N2 is located to the side of the window at an 

angle of approximately 128° (Oring–(N2)–Oring) whereas the 

CO2 was centered (i.e., 180°, Fig. 2). The closest N2-framework 

interactions are approximately 3.1 Å to 3.5 Å from nitrogen 

to Oframwork. The N2 molecules, unlike the CO2 molecules, do 

not orient perpendicular to the symmetry center of the 8-ring 

window. The ADPs for N2 are large, suggesting that there is more 

disorder in the location of the N2. 

The origins of the overall high affinity for CO2 versus N2 in both 

forms of the zeolites determined here may stem from several 

key factors. They are: (1) the small pore size in zeolite SSZ-13 

restricts diffusion, (2) the pore window is an ideal diameter 

for adsorption of CO2 and unoccupied by cations, and (3) the 

difference in electrostatic interactions between the gases and 

both the H+ and Cu2+ frameworks. In SSZ-13, the 3.8 Å pore 

window is too small for easy diffusion of N2 (kinetic diameter, 

3.64 Å), while CO2 (3.30 Å) can more freely diffuse into the 

pores. This, coupled with the fact that the framework-CO2 

interaction is the ideal distance for adsorption in the window 

sites based on the van der Waals radii, leads to very high CO2:N2 

selectivity in SSZ-13. Additionally, if we consider the difference 

in the quadrupole interactions between framework and CO2 

(quadrupole moment = 13.4 x 10-40 C m2

, polarizability = 26.3 

x 10-25 cm3

) and N2 (quadrupole moment = 4.7 x 10-40 C m2 , 

polarizability = 17.7 x 10-25 cm3

) over the “length” of the guest 

molecule, the result is a much stronger affinity for CO2 over 

N2 in the window site. This was demonstrated with density 

functional theory (DFT) calculations [3]. 

FIGURE 3: A cut-away view 

of the cage showing the 

primary (A) and secondary 

(B) CO2 adsorption sites 

(black = carbons, yellow = 

oxygens) for the highest 

CO2 dosing

This newfound knowledge of CO2-framework interaction 

directly mediated in the center of the 8-ring window has 

potentially broad applicability. The quadrupolar interactions 

should also be valid in the description of other zeolites with high 

selectivities and 8-ring windows. In the analogous zeolite CHA, 

albeit at differing Si/Al ratios, the CO2 and N2 adsorption in 

the Li, Na, and K exchanged derivatives follows a trend that is 

based on the properties of the cations (size and polarizability) 

[7]. Diffraction experiments, such as these, are able to determine 

the extent of this effect, if any, with different alkali metal content 

controlled by varying Si/Al2 ratios. Through varying the Si/Al 

ratio, it may be possible to modify the Cu2+ content of SSZ-13, 

further tuning and enhancing the overall uptake and separation 

capacity. NPD combined with in situ gas dosing has proven ideal 

for systematic tuning of materials for industrial gas separation 

applications. 

References 

[1] D.M. D’Alessandro, B. Smit, J.R. Long, Angew. Chem. Int. Ed. 

49, 6058 (2010). 

[2] E.D. Bloch, W.L. Queen, R. Krishna, J.M. Zadrozny, C.M. Brown, 

J.R. Long, Science 335, 1606 (2012). 

[3] M.R. Hudson, W.L. Queen, J.A. Mason, D.W. Fickel, R.F. Lobo, 

C.M. Brown, J.Am. Chem. Soc. 134, 1970 (2012). 

[4] D.W. Fickel, R.F. Lobo, J. Phys. Chem. C 114, 1633, (2009). 

[5] W.L. Queen, C.M. Brown, D.K. Britt, P. Zajdel, M.R. Hudson, 

O.M. Yaghi, J. Phys. Chem. C 115, 24915 (2011). 

[6] J.H. Kwak,  	H. Zhu,  J.H. Lee ,  C.H.F. Peden and J. Szanyi, 

Chem. Commun. 48, 4758, (2012).

[7] F.N. Ridha, P.A. Webley, Micro. Meso. Mater. 132, 22 (2010). 

Chemical Physics
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 17 
Chemical Physics
 

Evolving structure of the solid electrolyte 

interphase in Li-ion batteries characterized by 

in situ neutron reflectometry 

J.A. Dura1, J.E. Owejan2, J.P. Owejan2, and S.C. DeCaluwe3 

E

lectrochemical energy storage is a critical component in 

efforts to transform our energy base from fossil fuels to 

modern renewable energy sources. Lithium ion batteries 

in electric and hybrid automobiles present the greatest 

potential for its large scale application. In these, economic 

considerations are driving ongoing research and development to 

improve durability and prevent capacity fade. At the extremely 

high anode chemical potential which provides Li-ion batteries 

with high energy and power density, the electrolyte decomposes, 

coating the electrode surface with a layer of lithium-containing 

compounds called the Solid Electrolyte Interphase (SEI). This 

reduces the available amount of active lithium and therefore the 

capacity of the cell. The SEI, however, passivates the surface, 

greatly reducing (though not completely eliminating) further 

electrolyte decomposition. 

Despite its critical significance, structural characterization of 

the SEI is currently incomplete because of the highly reactive 

and delicate nature of both the SEI and the electrolyte. Many 

previous investigations have sought to understand the SEI layer, 

primarily by ex situ spectroscopy or microscopy techniques. 

It is essential to expand these measurements to study the 

growth, composition, thickness, and porosity of the SEI in 

situ as a function of operating conditions such as potential, 

temperature, age, depth and number of cycles, or selection of 

material components including electrolyte additives. Neutron 

reflectometry (NR) determines the depth profile of the scattering 

length density (SLD) which can be related to the composition 

profile. In particular, since it is sensitive to the light elements in 

SEI compounds, NR is ideal for in situ Li-ion battery studies. 

Additionally, isotopic differences in SLD for H and Li allow 

their accurate depth profiles and/or isotopic labeling of sources 

of these elements. Similarly, exchange of working fluids with 

different SLDs allows direct measurement of the porosity depth 

profile. This study highlights the first use of in situ NR to 

measure the SEI structure in a lithium battery [1]. 

NR data were taken using AND/R at the NCNR, first of the 

as-grown Cu cathode in the electrolyte-filled cell at open circuit 

voltage (OCV), i.e., no current that would cause an SEI to grow 

was allowed (test point a-OCV). An SEI was then produced 

by running 10 cyclic voltamograms (CV), in which current is 

measured during a cyclic voltage sweep, followed by a hold at 

250 mV during which NR data were again taken (test point 

b-250). These two data sets (Fig. 1) show distinct differences in 

oscillation peak amplitude and position vs. Q, due to the effects 

of the SEI layer on the scattering. A simultaneous fit of these 

data sets reveals that a temporary copper carbonate/hydroxide 

layer had formed on the initial unoxidized Cu surface. After 

the CV scans, the copper carbonate/hydroxide layer is removed 

and a single 4.0 nm (3.6 to 4.2) nm thick SEI layer is deposited 

with an SLD well below the level of the electrolyte, seen at the 

left in the inset to Fig. 1. (Numbers in parentheses are the 68 % 

confidence range). 

FIGURE 1: Neutron reflectivity vs . Q at a-OCV, open circuit voltage, 

and b-250 during a hold at 250 mV after 10 cyclic voltamograms . Solid 

lines are the best simultaneous fit to the two data sets . Inset − the best 

fits SLD profiles . Dark and lighter shaded regions are 68 % and 95 % 

confidence intervals, respectively . 

The next test point c-150 was taken after 10 more CV cycles 

were run, followed by a hold at 150 mV. The SEI layer at test 

point c-150 is remarkably similar to the previous test point, 

b-250, but slightly thicker at 4.5 nm (4.0 to 4.7) nm due to 

the lower reduction potential and/or additional 10 CV cycles. 

Subsequently, six data sets (d-1000 through i-7) were taken at 

various potentials without further CV cycling, as summarized in 

the right inset to Fig. 2 which also shows representative CV curves 

taken throughout the experiments. The NR data for test points 

c-150 through i-7 each had excellent fits to a model that held all 

parameters at the same values determined from the simultaneous 

fit (Fig.1), except the Cu and SEI thicknesses, the SEI SLD, and 

both interface widths surrounding the SEI. The resultant SLD 

profiles from these fits (along with test point b-250) are shown in 

Fig. 2. Key fitting parameters are summarized in Fig. 3. 

1 NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 

2 Electrochemical Energy Research Laboratory, General Motors, Honeoye Falls, New York 14472 

3 Colorado School of Mines, Golden, CO, 80401 

18 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

 

FIGURE 2: The SLD as a function of depth for the SEI region . The left 

inset shows the full SLD profile with the fits co-aligned on the Ti layer . 

The right inset shows selected CV scans . Test points b-250 to i-7 denote 

the location of potentiostatic holds for NR testing . 

FIGURE 3: Selected fitting parameters and hold potential as a function 

of test point . Cu thickness is plotted relative to the thickness measured 

in test point a-OCV . 

These fits and associated uncertainties clearly show that the SEI 

on the copper surface changes in both composition and thickness 

as a function of voltage. The SEI thickness grows steadily from 

b-250 to d-1000, from 3.96 nm to 4.75 nm, while the SLD 

increases, demonstrating that the SEI, originally rich in lithium, 

incorporates molecules with relatively less lithium. The layer 

shrinks slightly at e-2300 (i.e., at 2300 mV), presumably due to 

the oxidation current and/or solubility of several molecules. After 

e-2300, stable for carbonate-based electrolytes, to f-1500, the SEI 

doubles in thickness and increases in SLD. There is little change 

when the potential is decreased at test point g-800. 

The next two test points, h-250 and i-7, demonstrate increasing 

reduction of the SLD as the potential is lowered, indicating a 

net gain of lithium-containing or low density molecules. The 

large SLD gradients seen at the SEI/electrolyte interface in these 

last two test points can be interpreted in two ways. A one-layer 

interpretation shows the layer thickness roughly constant or 

slightly decreasing as the SLD decreases (in going from test point 

g-800 through i-7), which can be interpreted as that the SEI layer 

as a whole is substituting high SLD material (Li-poor or dense) 

with lower SLD material (Li-rich or less dense). Alternatively, 

examination of the SLD profile indicates a layer that increases in 

thickness from g-800 to h-250 and less so to i-7, wherein the low 

SLD material is added near the Cu interface. This composition 

gradient interpretation would indicate that Li-rich material is 

added near the Cu interface while the already deposited material 

remains adjacent to the electrolyte and is roughened. This view 

is supported by the net charge accumulation (not shown) during 

these potential holds, indicating that molecules were added to 

the SEI. Future measurements employing Li isotopic substitution 

will be able to distinguish between these two possibilities. 

The composition of the SEI was determined by x-ray 

photoelectron spectroscopy, XPS, obtained after the NR 

experiment. The amount of each component was adjusted 

within XPS variability to provide a composition model of the 

SEI consistent with the NR SLD and thickness. From the 

amount of each molecule the charge required to produce the 

SEI is calculated. The measured charge divided by modeled 

charge increases from 1.85 at test point b-250 to 5.39 at test 

point i-7. This is most likely due to the SEI molecules which 

have contributed to the charge accumulation and then have 

subsequently re-dissolved into the electrolyte. 

In sum, a well-functioning electrochemical cell with electrode materials compatible with NR measurements has been 

developed and used to successfully measure the SEI for a range 

of potentiostatic holds. It has been demonstrated that NR is 

highly effective for investigating in situ growth and evolution of 

the SEI. These results are the first direct measurements of critical 

SEI properties (such as thickness, porosity, layer structures, 

gradients, and chemical composition) on an operating Li cell, 

without confounding experimental artifacts associated with ex 

situ techniques. These results include an SEI thickness of 4.0 to 

4.5 nm for 10 to 20 CV cycles growing to 8.9 nm after a series 

of potentiostatic holds that approximates a charge/ discharge 

cycle. The SLD profile of several test points indicates a lack 

of significant gradients, contrary to proposed structures in 

the literature. The SEI thickness grew most rapidly at the first 

test point that lies in the region of electrolyte instability. Due 

to its passivating nature, growth of the SEI thickness slowed 

subsequent to this, even at the lowest potentials examined. 

However, Li-rich molecules having a lower SLD substitute into 

the SEI at lower potentials, as demonstrated when moving from 

test points g-800 through i-7. 

Future implications of this study include the capability to 

directly and quantitatively study SEI properties as a function 

of electrolyte composition (including additives), temperature, 

voltage, current, cycling and time, etc. In addition, the direct 

measurement of critical SEI parameters, both presented herein 

and in the future under various conditions, will lead to marked 

improvements in the accuracy of numerical simulations of 

processes in Li batteries involving the formation of and ion 

transport within the SEI. Taken together, such NR investigations 

will enable future systematic improvements for commercial 

device performance, affordability, and sustainability. 

References 

[1]	 J.E. Owejan, J.P. Owejan, S.C. DeCaluwe, J.A. Dura, Chem. Mater. 24, 

2133 (2012). 

Chemical Physics
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 19 
 

Chemical Physics


Activated dihydrogen bonding to a supported 

organometallic compound 

J.M. Simmons1, T. Yildirim1, A. Hamaed2, D.M. Antonelli2,3, M.I. Webb4, C.J. Walsby4 

On-board hydrogen storage in fuel-cell-powered vehicles 

is a major component of the national need to achieve 

energy independence and protect the environment. 

Fundamental breakthrough discoveries in materials 

science will be required to achieve light-weight, low-volume, safe, 

economical and recyclable storage technology. The main obstacles 

in hydrogen storage are slow kinetics, poor reversibility and high 

dehydrogenation temperatures for the chemical hydrides, and 

very low desorption temperatures/energies for the physisorption 

materials such as metal-organic-frameworks or porous carbons. 

The optimum conditions for viable room temperature hydrogen 

storage require materials that possess isosteric heats of adsorption 

in between that of standard physisorbers and chemisorbers, 

typically in the (20 to 30) kJ/mol regime. Theoretical efforts 

have shown that the incorporation of transition metal atoms 

onto a porous support can provide such binding energies at 

multiple hydrogen molecule adsorption sites [1]. The origin of 

this surprising finding can be traced back to dihydrogen Kubas 

complexes in which charge transfer from metal d-orbitals to 

hydrogen antibonding orbitals controls the strength of the 

dihydrogen metal interaction and causes the H-H bond to 

elongate [2]. However, despite a very large number of theoretical 

efforts, there has been no direct experimental proof of these 

predictions. Here we highlight our work [3] presenting such 

evidence for dihydrogen-Ti binding on a silica-supported Ti(III) 

organometallic complex using detailed sorption and inelastic 

neutron scattering (INS) measurements. Our experimental 

findings are further supported by extensive density-functional 

theory (DFT) and reaction path calculations. 

The sample (Ti-HMS) is formed by grafting tetrabenzyl-titanium 

onto a porous silica by attachment to the surface hydroxyls, then 

slowly heating to reduce the titanium to the +3 oxidation state 

as confirmed by electron paramagnetic resonance spectroscopy. 

Prompt Gamma Neutron Activation Analysis (PGAA) indicates 

0.6 mmol titanium per gram of Ti-HMS. Given the highly 

heterogeneous nature of silica surfaces, there are a number of 

ways the titanium could bond to the surface, each of which 

can have important effects on the final dihydrogen state. To 

better understand the starting chemistries, we have studied 

the vibrational structure of Ti-HMS using the Filter Analyzer 

Neutron Spectrometer, and have compared the measurements 

to spectra calculated for energy minimized structures in several 

possible bonding motifs using DFT. 

FIGURE 1: Experimental INS spectrum of the host Ti-HMS measured at 

4 K as compared to the DFT calculated spectra The computed energyminimized structures are shown for two bonding arrangements, geminal 

and vicinal . In both structures, the highly reactive Ti(III) ion is protected by 

the benzyl ligand bending towards the ion, creating a steric hindrance to 

incoming reactants and acting like a gate

In Fig. 1, we show two cases: geminal bonding, where the 

starting hydroxyls are attached to the same silicon atom, and 

vicinal bonding where the oxygens are on adjacent silicon atoms. 

Though the INS spectrum is dominated by the scattering from 

the benzyl ligand, it is subtly affected by the surface attachment. 

In both structures, the initially vertical benzyl ligand bends over 

to cover the Ti(III) ion, acting like a gate. It is believed that 

this shielding stabilizes the Ti(III) ion against surface hydrolysis 

reactions and is a critical component to the dihydrogen 

formation discussed below. For clarity, we will focus on the 

geminal attachment; other cases are presented in Ref. [3]. 

As shown in Fig. 2, low temperature adsorption of hydrogen 

leads to simple physisorption, with complete reversibility, 

modest isosteric heat of adsorption, ≈ 5.5 kJ/mol, and uptakes 

that are consistent with the ≈ 1100 m2

/g apparent surface area. 

Physisorption is also apparent by INS investigations in which 

the Ti-HMS sample is exposed in situ to hydrogen at 50 K. After 

subtracting the bare Ti-HMS spectrum, the signal due to the 

adsorbed hydrogen shows weak molecular rotational peaks near 

12.0 meV and 14.7 meV atop a large recoil background that 

1 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg MD 20899
 

2 University of Windsor; Windsor, ON, N9B 3P4 (Canada)
 

3 University of Glamorgan; Pontypridd CF37 1DL (UK)
 

4 Simon Fraser University; Burnaby, BC, V5A 1S6 (Canada)
 

20 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

 

comes from billiard-like scattering of weakly bound hydrogen 

molecules. Though hydrogen sorption is slightly improved over 

that of the bare silica, there is nothing to indicate the presence of 

a dihydrogen complex. 

FIGURE 2: (a) Hydrogen sorption isotherms, and b) backgroundsubtracted INS spectra showing fully reversible physisorption at 

low temperature and partially irreversible sorption near room 

temperature . In (b), the INS spectrum of the low temperature 

adsorbed hydrogen is dominated by a weak rotational peak on top 

of a large recoil background, while the room temperature adsorbed 

hydrogen shows well-defined modes . 

Surprisingly, sorption at room temperature shows irreversible 

behavior with a significant amount of hydrogen remaining after 

evacuation (Fig. 2a, inset). Approximately 1 mmol of H2

 per 

gram of Ti-HMS is retained corresponding to ≈ 1.6 hydrogen 

molecules per titanium atom, based on PGAA measurements. 

To confirm the irreversibility, Ti-HMS was exposed to room 

temperature hydrogen, briefly evacuated at room temperature 

to remove all physisorbed gas, and then cooled to 4 K for 

INS measurements. The difference is readily apparent in Fig. 

2: the spectrum of the low temperature adsorbed hydrogen is 

dominated by hydrogen recoil, whereas the room temperature 

adsorbed hydrogen spectrum shows several well defined 

rotational/vibrational modes. Further, INS shows no loss of 

signal arising from the benzyl ligands and thus the additional 

features are due only to the adsorbed hydrogen. Critically 

for potential applications, the final complex is stable for long 

periods of time when stored near room temperature but can be 

removed under mild conditions. After storing the sample at room 

temperature for 40 days and evacuating to remove any desorbed 

hydrogen, the INS spectrum was quantitatively unchanged, and 

attempts to add more hydrogen at room temperature showed no 

increase in uptake. However, evacuating the sample at 350 K led 

to the release of all adsorbed hydrogen [3]. 

To understand the reversible physisorption at low temperature 

and irreversible adsorption at room temperature with mild 

desorption temperatures, and to probe the possibility that this 

behavior corresponds to the sought after dihydrogen complex, 

we turn again to DFT. In Fig. 3 we present reaction path 

calculations of the structure and relative energy as the hydrogen 

adsorbs from the gas phase. A hydrogen molecule starts far from 

the titanium and retains the unperturbed 0.76 Å bond length. As 

the hydrogen moves toward the titanium, there is an appreciable 

increase in the total energy of the system due largely to the 

FIGURE 3: Relaxed molecular structures and relative energy as 

hydrogen adsorbs to form the dihydrogen complex . The short Ti—H2 

distance and H—H bond elongation are consistent with dihydrogen 

bonding . The dihydrogen complex is more stable than a physisorbed 

molecule and the calculated activation barrier is consistent with room 

temperature adsorption . 

flexure of the benzyl ligand away from the titanium, opening 

the “gate”, leaving the highly reactive Ti(III) more exposed. 

Once the hydrogen is close enough to directly interact with 

the titanium, the energy sharply decreases and is accompanied 

by an elongation of the H—H bond from 0.76 Å to 0.8 Å. 

The final Ti—H2 distance is around 2 Å and is much smaller 

than would be expected for physisorbed H2. The H—H bond 

elongation and close proximity of the adsorbed hydrogen to 

the titanium are signatures of dihydrogen bonding. It is notable 

that the ≈ 240 meV activation barrier effectively prohibits low 

temperature formation of the dihydrogen state but allows for 

room temperature adsorption, and the dihydrogen state is more 

stable by ≈ 100 meV, enabling hydrogen release under modest 

heating. 

To summarize, we have used inelastic neutron scattering, gas 

sorption and first principles DFT to show that specially prepared 

light transition metal complexes can support dihydrogen bonding, 

providing experimental support for earlier predictions. The close 

correlation between first principles DFT and INS lends strong 

support for the formation of the dihydrogen complex. The key 

obstacle to dihydrogen formation is the creation of a reduced 

transition metal adsorption site that is sufficiently stabilized 

through ligand control while not inhibiting the adsorption of 

hydrogen. In Ti-HMS, the flexibility of the benzyl ligand is 

important for stabilizing the Ti(III) ion, acting as a trap door/ 

gate-keeper to the adsorption of hydrogen near room temperature. 

Once formed, the dihydrogen complex is quite stable, persisting 

for at least 40 days without loss of hydrogen but able to release the 

hydrogen under mild heating conditions. In light of these results, 

it is worth noting that in the search for new hydrogen storage 

materials, one should not limit measurements to 77 K (a common 

procedure) but should also check adsorption isotherms at room or 

higher temperatures for possible activated binding. 

References 

[1] T. Yildirim and S. Ciraci , Phys. Rev. Lett. 94, 175501 

(2005). 

[2] G. J. Kubas, J. Organomet. Chem. 635, 37 (2001). 

[3] J. M. Simmons, T. Yildirim, A. Hamaed, D. M. 

Antonelli, M. I. Webb, C. J. Walsby, Chem. – Eur. J. 18, 

4170 (2012). 

Chemical Physics
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 21 
Condensed Matter
 

Electronic delocalization in the correlation gap 

insulator LaMnPO 

J. W. Simonson1, D. E. McNally1, Z. P. Yin1,2, M. Pezzoli1,2, J. Guo3, J. Liu4, K. Post5, A. Efimenko6 , 

N. Hollmann6

, Z. Hu6, H.-J. Lin7, C. T. Chen7, C. Marques1, V. Leyva1, G. Smith1, J. W. Lynn8, L. Sun3, G. 

Kotliar2, D. N. Basov5, L. H. Tjeng6, and M. C. Aronson1,9 

T

he unexpected discovery of high TC superconductivity 

in cuprates suggests that the highest TCs occur when 

pressure or doping transform the localized and momentbearing electrons in antiferromagnetic insulators into 

itinerant carriers in a metal, where magnetism is preserved in 

the form of strong correlations. The absence of this transition in 

Fe-based superconductors may limit their TCs, but even larger 

TCs may be possible in their isostructural Mn analogs, which 

are antiferromagnetic insulators like the cuprates. LaMnPO is 

isostructural to superconducting LaFeAsO, with an insulating 

gap of ≈ 0.8 eV and a moment of 3.2 μB/Mn attesting to strong 

Hunds rule correlations. Electronic structure calculations 

indicate that charge fluctuations are surprisingly large, 

suggesting proximity to electronic delocalization, and indeed 

delocalization occurs under quite modest pressures via two steps 

[1]. The insulating gap vanishes near 9 GPa, and the resulting 

antiferromagnetic metal is driven to a quantum critical point 

where the Mn moment collapses at ≈ 30 GPa (Fig. 1a). While 

these seem like large pressures, they correspond to a volume 

reduction of only 10 %, similar to the values required to induce 

superconductivity itself in some Fe-pnictide compounds. 

Neutron diffraction and inelastic scattering show intriguing 

similarities of the magnetic structure and excitations of LaMnPO 

to those of its Fe-based superconducting relatives. Figure 1b 

shows that the Néel temperature TN of LaMnPO is (375 ± 5) K. 

However, unlike the iron-based superconductors, charge doping 

in LaMnPO1-xFx has little effect on either TN or the ordered 

moment, which at T = 0 is 3.28 μB/Mn in LaMnPO. The 

magnetic structure of tetragonal LaMnPO consists of ab planes 

where the Mn moments are arranged in an antiferromagnetic 

checkerboard pattern as shown in the inset of Fig. 1(b). Nearest1 Stony Brook University; Brook, NY 11794 

2 Rutgers University; , NJ 08854 

FIGURE 1: (a) The pressure dependencies of the band gap (green 

circles) and ordered Mn moment (red circles) in LaMnPO from LSDA 

calculations Dashed line at 9 GPa indicates the metal-insulator transition 

(MIT ) where the charge gap vanishes Dashed line at 30 GPa (QCP) 

indicates full electronic delocalization, where the Mn moment and also 

antiferromagnetic order collapse (b) Temperature dependencies of the 

ordered Mn moment μ in LaMnPO F for x = 0 (red), 0 07 (magenta), AF 1-x x

0 10 (green), and 0 21 (blue), taken from the temperature dependence of 

the (100) magnetic peak in neutron diffraction measurements The solid 

curve is a least-squares fit to the power law M ~ (TN -T)

-β

 with an Isinglike exponent β = 0 28 ± 0 02 (solid line) . Inset: the magnetic structure 

of antiferromagnetic LaMnPO, where only the moment-bearing Mn 

moments are shown . 

neighbor spins along the c-axis are parallel (ferromagnetic 

alignment) as previously reported [2]. This magnetic structure 

of tetragonal LaMnPO is more like that of the cuprates than 

the ones that are found in Fe-based superconductors, where the 

antiferromagnetic phase is orthorhombic and the magnetic order 

is stripe-like [3]. 

The magnetic susceptibility of LaMnPO is nearly temperatureindependent up to 800 K, with no sign of antiferromagnetic 

3 Institute of Physics and Beijing National Laboratory for Condensed Matter Physics; Chinese Academy of Sciences; 100190, P . R . China . 

4 Institute of High Energy Physics; Academy of Sciences; 100039, P . R . China 

5 University of California San Diego; Jolla, CA 92093 

6 Max-Planck-Institut fur Chemische Physik fester Stoffe; D-01187 Dresden, Germany 

7 National Synchrotron Radiation Research Center (NSRR); 101 Hsin-Ann Road; Hsinchu 30077, Taiwan 

8 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg, MD 20899 

9 Brookhaven National Laboratory; Upton, NY 11973 

22 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

 

order at 375 K. This suggests that LaMnPO is a system with 

very strong exchange interactions, and so inelastic neutron 

scattering measurements were carried out on a polycrystalline 

sample of LaMnPO using BT-7 to test this hypothesis. Energy 

scans performed around the antiferromagnetic wave vector 

Q = 1.55 Å-1 are shown in Fig. 2(a). At low temperature we 

find a spin gap Δ of ≈ 7.5 meV, while the magnetic intensity 

above this energy is constant up to the highest energy of 

25 meV probed in our experiment. This indicates a very steep 

spin wave dispersion in LaMnPO, consistent with an exchange 

interaction that is much larger than 25 meV. With increasing 

temperature the data in Figure 2a show that the intensity of 

the spin wave scattering increases as expected for the Bose 

population factor, while the spin gap decreases and vanishes at 

the Néel temperature. Thus in the paramagnetic state (T > TN) 

the gapped spin wave scattering is replaced by strong quasielastic 

scattering centered at the antiferromagnetic wave vector, as is 

found in some of the Fe-pnictide superconductors [4]. Figure 2b 

demonstrates that strong short-ranged correlations persist well 

into the paramagnetic state, indicating that this paramagnetic 

scattering in LaMnPO is emphatically not that of individual Mn 

moments, but rather reflects the dynamical correlations of strong 

exchange coupled Mn-moments. 

Pressure dependent x-ray diffraction measurements of the 

structure have been carried out, and electronic band calculations 

based on these crystallographic results were performed to 

determine the effects of pressure on the electronic structure 

and charge and spin correlations. Surprisingly, it was revealed 

that only modest pressures of 9 GPa are required to transform 

LaMnPO from an antiferromagnetic insulator to a metallic 

antiferromagnet [1]. Moreover, the calculated magnetic moment 

above an orthorhombic distortion observed at 16 GPa becomes 

less than 1 μB. These properties are in striking analogy to the 

isostructural metallic iron-based superconducting host LaFeAsO, 

which undergoes a tetragonal-to-orthorhombic structural 

transition with temperature followed by antiferromagnetic 

ordering with an ordered moment of only 0.35 μB [3]. A second 

transition is predicted to occur at 30 GPa, where the complete 

collapse of the magnetic moment occurs [1]. The proximity to 

these charge and moment delocalization transitions in LaMnPO 

results in a metallic state with highly correlated electrons, the 

familiar breeding ground of superconductivity. 

How promising are Mn-based compounds as potential 

superconductors? Superconductivity is achieved in compounds 

where the interactions are exquisitely balanced between metal 

and insulator, and where magnetic order is on the verge of 

complete destruction. Our neutron scattering measurements 

show an unexpected degree of similarity between the magnetic 

structure and spin excitation spectrum of LaMnPO and the 

Fe-pnictide superconductors. Achieving higher TC may require 

something more. Perhaps the cuprates have higher TCs than the 

Fe-pnictides because the spin correlations in the cuprates are 

strong enough to make them insulating in the absence of doping. 

The present work suggests that electron correlations in the Mnpnictides are very strong and may be even stronger than the 

cuprates, indicating that Mn-based compounds like LaMnPO 

could provide a new avenue to superconductivity, and perhaps 

with higher TCs than currently available. 

FIGURE 2: (a) Energy dependence of the magnetic intensity for QAF = 1 .55 

Å-1 (the (100) antiferromagnetic wave vector) at different temperatures 

(black: 25 K, red: 150 K, green: 250 K, purple: 330 K, blue: 355 K) At low 

T there is a spin gap of 7 5 meV, while the magnetic intensity above 

this energy is constant indicating very steep spin wave dispersion The 

intensity increases with increasing temperature due to the thermal 

population factor, while the gap decreases Inset: temperature 

dependence of spin gap D (b) Wave vector dependencies of the 

scattered intensity for fixed E = 15 meV at different temperatures 

above and below the antiferromagnetic order temperature TN = 375 K, 

indicating that very strong spin correlations persist in the paramagnetic 

state The observed asymmetry of the scattering is due to a second 

antiferromagnetic wave vector (101) at 1 71 Å-1 . Data were obtained using 

the BT-7 triple axis spectrometer

References 

[1] J.W. Simonson, Z. Yin, M. Pezzoli, J. Guo, J. Liu, K. 

Post, A. Efimenko, N. Hollmann, Z. Hu, H.-J. Lin, 

C.T. Chen, C. Marques, V. Leyva, G. Smith, J.W. Lynn, 

L. Sun, G. Kotliar, D.N. Basov, L.H. Tjeng, and M.C. 

Aronson, Proceedings National Academy of Science 109, 

10751 (E1815) (2012). 

[2] H. Yanagi, T. Watanabe, K. Kodama, S. Iikubo, S-I. 

Shamoto, T. Kamiya, M. Hirano, and H. Hosono, J. 

Appl. Phys. 105, 093916 (2009). 

[3] C. de la Cruz, Q. Huang, J.W. Lynn, J. Li, W. Ratcliff 

II, J.L. Zarestky, H.A. Mook, G.F. Chen, J.L. Luo, N.L. 

Wang, and P. Dai, Nature 453, 899 (2008). 

[4] M. Wang, X.C. Wang, D.L. Abernathy, L.W. Harriger, 

H.Q. Luo, Y. Zhao, J.W. Lynn, Q.Q. Liu, C.Q. 

Jin, Chen Fang, J. Hu, and P. Dai, Phys. Rev. B83, 

220515(R) (2011). 

Condensed Matter
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 23 
Condensed Matter
 

Spin-orbital short-range order on a honeycomb-based 

lattice 

S. Nakatsuji1, K. Kuga1, K. Kimura1, R. Satake2, N. Katayama2, E. Nishibori2, H. Sawa2, R. Ishii3, M. Hagiwara3, F. Bridges4, T. 

U. Ito5, W. Higemoto5, Y. Karaki6, M. Halim7, A. A. Nugroho7, J. A. Rodriguez-Rivera8,9, M. A. Green8,9, C. Broholm8,10 

Aspin liquid within a solid is a state of matter 

without static spin order at low temperatures, 

despite strong interactions between local magnetic 

moments on a lattice. It is thought that competing 

(frustrated) interactions can lead to this order, but no definite 

realization on a 2D honeycomb lattice has been documented. 

Magnetically frustrated Ba3CuSb2O9 has some of the anticipated 

characteristics. Inelastic neutron scattering is gapless at a 

resolution of 0.2 meV but shows no temperature dependent 

elastic scattering between 25 K and 1.5 K. This indicates that 

spins in Ba3CuSb2O9 do not develop static order but remain in a 

fluctuating quantum state to the lowest temperatures [1]. 

The structure of Ba3CuSb2O9 was determined by synchrotron 

x-ray and neutron diffraction from single crystals and powder 

samples to be P63/mmc, different from a previously reported 

structure [2,3]. Inside, there is a 6H perovskite substructure 

with Cu-Sb “dumbbell” ordering (Fig. 1). This structure is 

oriented along the c axis connected through corner-sharing SbO6 

octahedral and Ba counterions. 

The dominant super-exchange interactions in the resulting 

structure are associated with Cu-O-O-Cu pathways. In Fig. 1 

we identify J(1) and J(2) as the largest interactions, thanks to the 

s bonding component of O 2p-2p hybridization. For the same 

reason, J(3) is an order of magnitude smaller due to the absence 

of O-O s bonding. The resulting interactions give us a quasitwo-dimensional spin orbital system with the Cu2+ forming a 

honeycomb lattice with identical nearest-neighbor interactions. 

The out of the plane Cu’ site in the “dumbbell” structure forms a 

frustrated isosceles spin triangle interacting via J(2) with two Cu 

atoms in the hexagonal (honeycomb) structure. 

FIGURE 1: Ba3CuSb2O9 structure (Ba removed for clarity) showing the 2D 

honeycomb lattice with Cu-Sb “dumbbells” The O 2p orbitals controlling 

J(1) (green) and J(2) (blue) super-exchange magnetic coupling between Cu 

ions (within the pink circles) are shown as colored blobs . The disordered 

structure results from frozen-in frustrated interactions between the Cu 

and Cu’ ions on the isosceles triangles (in the green circle) that propagate 

the disorder into the Cu ions on the honeycomb

Depending of the stoichiometry, the sample is susceptible to 

a Jahn-Teller (JT) type transition. For example, if the Cu/ 

Sb stoichiometry differs from 2/1 by ≈ 10 %, the compound 

displays a JT type transition from hexagonal to orthorhombic 

at T ≈ 200 K. Those samples become orthorhombic at low 

temperatures. For samples with Cu/Sb ≈ 1 the synchrotron x-ray 

diffraction data show that the majority phase is hexagonal at 

T = 12 K. The same data for T < 30 K show subtle remnants of 

the JT- distorted orthorhombic phase. 

1 University of Tokyo; Kashiwa, Chiba 277-8581, Japan 2 Nagoya University; Nagoya 464-8603, Japan 3 KYOKUGEN; Osaka University; Toyonaka, Osaka 560-8531, Japan 4 University of California; Santa Cruz, CA 95064 5 Advanced Science Research Center; Japan Atomic Energy Agency; Tokai, Ibaraki 319-1195, Japan 6 University of the Ryukyus; Nishihara, Okinawa 903-0213, Japan 7 Institut Teknologi Bandung, Jl; Ganesha 10, Bandung 40132, Indonesia 8 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg, MD 20899 9 University of Maryland; College Park, MD 20742 10 Johns Hopkins University; Baltimore, MD 21218 

24 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
FIGURE 2: (a) Inverse susceptibility 1/(χ-χ0

) as a function of temperature 

for polycrystalline hexagonal and single crystal orthorhombic samples for 

applied fields along [100] and [001] The diamagnetic contribution is χ0 ≈ 

-4p × 10-10 (m3

/mol-Cu) Inset: χ vs T at two frequencies for these samples

(b) Magnetic specific heat CM as a function of T at zero field and (inset) nonzero fields . The data indicate that hexagonal samples have more degrees 

of freedom than orthorhombic ones, consistent with enhanced spin 

fluctuations . 

Susceptibility measurements for the hexagonal samples (Fig. 2a) 

indicate magnetic isotropy. In the hexagonal phase for 300 K 

< T < 600 K, the Curie-Weiss fitting consistently yields an 

effective moment, Peff = 1.87 μB and g ≈ 2.15 for both single 

crystal and polycrystalline samples. The single crystal samples 

shows a Curie-Weiss temperature QW = -42 K in both field 

directions and QW = -47 K for polycrystalline samples. Using 

[(-z)/3]JS(S+1)] with –z = 10/3 and S = 1⁄2, this yields J(1) ≈ J(2) 

= 52 K which are typical values for Cu-O-O-Cu super-exchange. 

Fig. 2b shows the electronic specific heat CM as a function of the 

temperature. At 5 T, the field induces a Schottky anomaly, which 

indicates that a significant part of the low-T specific heat can 

be associated with orphan spins found in all samples. The zerofield peak at 20 K, in the hexagonal samples indicates enhanced 

fluctuations on an energy range that approximately matches the 

spin exchange constants. 

Fig. 3 shows inelastic neutron scattering data taken at MACS ~ on a powder sample at different temperatures. S(Q,w) is the 

spherically averaged dynamic spin correlation function. The 

data (Fig. 3e) shows direct evidence for a peak in the magnetic 

excitation at ≈ 6 meV (70 K) near the values of J(1) ≈ J(2) = 54 

K indicated by the susceptibility data. The low T spectrum (Fig. 

3c) appears to be gapless at the MACS resolution of ≈ 0.2 meV. 

Low T (1.4 K) elastic neutron scattering data subtracted from 

high T (25 K) data do not show a frozen moment developing 

between these temperatures. Figure 3d solid lines are the fit to a 

single-dimer correlation function. The wave vector dependence 

was obtained under the assumption of a separable dynamic ~ ~ correlation function, S(Q,w) = S(Q) f(w), and averaging the data 

from 1.5 meV to 10 meV. 

Condensed Matter 

FIGURE 3: Inelastic neutron scattering from polycrystalline Ba3CuSb2O9 

at T = 1 5 K, 25 K and 50 K (with inferred diffuse scattering subtracted) ~ S(Q,w) is the spherically averaged dynamic spin correlation function, Q 

the wave vector and ħw the energy transfer . The data in (e) show direct 

evidence for a peak in the magnetic excitation spectrum at ≈ 6 meV (70 K), 

near the values of J(1) ≈ J(2) = 54 K indicated by the susceptibility data

We conclude that the unit cell averaged spin and orbital 

configuration for Ba3CuSb2O9 retains hexagonal symmetry and 

does not develop a frozen moment at very low temperatures 

despite its being magnetically and structurally anisotropic on 

atomic length scales. The neutron scattering data also show 

a near-neighbor singlet formation with a range of coupling 

strengths that peaks near J(1) ≈ J(2). One explanation of this 

behavior is local static JT distortions not affecting the overall 

hexagonal geometry with a static orbital disorder that is seeded 

by the Cu’–Cu coupling; another explanation would be a 

dynamic JT distortion. The experiments done cannot identify 

which explanation is correct, but they have unveiled a new 

disordered magnetic structure on a honeycomb lattice. 

References 

[1] S. Nakatsuji et al., Science 336, 559 (2012). 

[2] V.P. Köhl, Z. Anorg. Allg. Chem. 442, 280 (1978). 

[3] H.D. Zhou et al., Phys. Rev. Lett. 106, 147204 (2011). 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 25 
 

 

Condensed Matter
 

Common origin of the two types of magnetic 

excitations in iron chalcogenide superconductors 

Songxue Chi,1,2, J. A. Rodriguez-Rivera,1,2 J. W. Lynn,1 Chenglin Zhang,3 D. Phelan,1 D. K. Singh,1,2 R. Paul,4 and 

Pengcheng Dai3,5 

T

o participate in superconductivity, electrons need 

help to overcome their natural repulsion for each 

other to form bound Cooper pairs. In conventional 

superconductors, this help comes from lattice vibrations, 

or phonons, but for the superconductivity found in ‘highTC’ copper oxides (cuprates), the transition temperature to 

superconductivity, TC, below which superconductivity sets in, is 

too high to be supported by phonons. The parent compounds 

of cuprates are insulating and antiferromagnetically (AFM) 

ordered, while superconductivity arises when holes or electrons 

are introduced through doping, with the AFM order suppressed. 

Mounting evidence has pointed to robust spin fluctuations as 

the pairing glue, yet how the electrons pair up in the high-TC 

superconductors (HTSCs) has yet to be resolved despite three 

decades of research. In 2008 a new class of Fe-based HTSCs 

was discovered, and again magnetism was found to play an 

essential role in the superconductivity, while the nature of the 

magnetism itself remains controversial. The work highlighted 

here explores the character of the magnetic spin fluctuations of 

the iron chalcogenides, and reveals two different components of 

the excitations that are found to be intimately connected to each 

other rather than separate as previously thought. 

The Fe superconductors can be classified into two groups: the 

ferropnictides (iron plus a column VB element of the periodic 

table) and ferrochalcogenides (iron plus a VIB element). The 

parent compounds of the two groups have many things in 

common: They have similar crystal structures; both are metallic 

and have similar Fermi surface (FS) topologies that control both 

the magnetic and electrical properties. Yet the AFM magnetic 

structures, and the associated spin excitations, of the two classes 

are quite different. The pnictides have a single stripe collinear 

AFM arrangement characterized by the vector (0.5,0.5,0.5) in 

momentum space. This is expected for the type of magnetism 

originating from itinerant conduction electrons through the 

mechanism of FS nesting. Fe1+yTe, on the other hand, has a 

diagonal double-stripe bicollinear order modulated along the 

(0.5,0,0.5) direction [1], which is 45° away from FS nesting wave 

vector. Additionally, the ordered moment in Fe1+yTe is much 

bigger—2 μB in contrast to less than 1 μB in the pnictides. Such 

a large moment has fueled debates over whether the nature of the 

magnetism in ferrochalcogenides originates from local moments, 

itinerant electrons, or both. 

The Fe1+yTe ‘parent’ system becomes superconducting when Te 

is replaced by Se. With doping the magnetic long range order 

is suppressed, while two types of collective spin excitations are 

observed. One set of excitations occurs in the low energy regime 

at the commensurate (CM) (0.5,0,0) wave vector position, 

while the other type consists of very energetic incommensurate 

(ICM) excitations (up to 200 meV) located around the (0.5,0.5, 

0) position. It was thought that these two types of excitations 

might arise from separate phases due to chemical inhomogeneity, 

impurity, or phase separation that exists in these materials, but 

we found that both types of excitations have a common origin 

and occur in the same phase. 

FIGURE 1: Contour plots of neutron scattering intensity in the (H,K,0) plane 

at energy transfers of (a) 1 5 meV (b) 6 0 meV . The data were collected 

at T = 1.5 K on MACS The arrows in (a) and (b) show the directions of the 

spectral intensities plotted in (c) and (d), respectively The open circles 

(d) are high resolution SPINS data that reveal the “hour-glass” dispersion 

characteristic of high temperature superconductors . 

1 NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland, 20899-6102 

2 Department of Materials Science and Engineering, University of Maryland, College Park, Maryland, 20742 

3 Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200 

4 Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, 20899-6102 

5 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China 

26 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
          

       

       

     

       

In order to investigate the relationship between the two types 

of magnetic excitations, single crystals of moderately doped 

non-superconducting Fe1.01Te0.72Se0.28 were used for this study. 

The actual compositions of the samples were determined with 

prompt gamma activation analysis (PGAA). Neutron scattering 

measurements were performed on the cold neutron MACS 

and SPINS spectrometers and the BT-7 thermal triple axis 

spectrometer. 

At low-energy transfers the CM type excitation is dominant 

with a broad peak at (0.5,0,0), as shown Fig. 1(a). As the energy 

increases the CM type scattering quickly diminishes in intensity 

while the two ICM peaks around (0.5,0.5,0) start to appear and 

intensify (Fig. 1(b)). At various energies, we performed cuts along 

[0.5,K] through the centers of both (0.5,0,0) and (0.5,0.5,0), 

which enabled us to track the evolution of the two excitations 

simultaneously. Constant-E cuts in the transverse [H,1−H] 

direction through (0.5,0.5,0) were also conducted, which yielded 

two symmetric ICM peaks, giving the dispersion of the ICM 

excitation. The combinations of these two cuts as a function of 

energy are shown in Figs. 1(c) and 1(d). Remarkably, the data 

reveal that there is a clear reciprocal interplay between the two 

types of spin excitations; the sudden disappearance of the CM 

excitation at around 6 meV is directly correlated with the energy 

where the twin ICM peaks increase spectral weight. Above about 

7 meV the spectral weight is constant, which indicates that the 

gap of the ICM excitations below 7 meV is not compensated 

by spectral gain at higher energies at the same wave vector. This 

again indicates that spectral weight is transferred between the 

two wave vectors and that the CM spectrum is at the cost of the 

ICM spectrum. Clearly, the spectral weight for these two types 

of excitations is inversely correlated, which rules out electronic 

phase separation or magnetic inhomogeneity as the origin of the 

two types of magnetic correlations. 

The connection of the CM and ICM excitations is clearly 

revealed by the behavior as a function of temperature. 

The (H,K,0) planar maps have been obtained at different 

temperatures between 1.5 K and 308 K for four typical energy 

transfers, one of which is shown in Fig. 2. Both types of magnetic 

correlations are so robust that they maintain their well-defined 

features up to the highest measured temperature for all the 

energy transfers. On warming, the CM spectrum at E = 1 meV 

(Fig.1(a)) starts to gain intensity at about 60 K, where the 

static order disappears, reaches its maximum at about 80 K and 

gradually decreases at higher temperatures. The ICM spectrum 

around (0.5,0.5), however, is clearly gapped below the transition 

temperature of the static AFM order. The similar T dependencies 

of the scattering in the paramagnetic phase (T > 60 K) further 

confirms that these two types of spin excitations are of the same 

nature. 

Another conspicuous feature in Fig. 1(d) is the dispersion toward 

(0.5,0.5,0) below 3 meV before its steep outward dispersion. The 

result of high wave vector resolution measurements on SPINS is 

over-plotted in Fig. 1(d), which confirms this hourglass-shaped 

FIGURE 2: Temperature dependence of the (a) CM and (b) ICM spectra at 

an energy transfer of 1 meV

dispersion as a characteristic feature of the highly correlated spin 

excitations found in the high-TC class of superconductors. 

Now that we know that the two types of excitations have a 

common origin, suppressing the CM-type correlations through 

doping Se cannot be simply understood as eliminating a 

coexisting phase. Rather, one has to treat the two excitations 

as one problem when trying to reveal the driving force for 

magnetism and superconductivity. In this sense, itinerant 

conduction electrons alone may not be able to provide a 

complete answer. The FS nesting describes the main features 

of the ICM excitations such as the hourglass dispersion near 

(0.5,0.5,0), but the FS near the X point does not appear to 

support the nesting scenario for the CM excitation. In a local 

moment picture, the magnetic ground state is governed by the 

coupling between magnetic ions through non-magnetic ions. 

The contest between the collinear and bi-collinear order is 

controlled by the competition between magnetic couplings at 

different sites, which have different Te/Se height dependencies. 

As Se replaces Te, the chalcogen height is reduced, which results 

in a less-favored bi-collinear CM order. The spin-wave spectrum 

centered at (0.5,0,0) that extends up to 60 meV in undoped 

FeTe is suppressed to lower energies, and is completely taken 

over by the ICM magnetism as the Se content increases well 

into the superconducting region. This scenario is supported by 

the reciprocal interplay between the two types of excitations and 

the temperature dependence presented in this study. However, 

it is not possible to understand the low-energy features such as 

the hourglass dispersion and the abnormal change of intensity 

and linewidth for the (0.5,0,0) CM spectrum with just a local 

spin picture. Our results call for a more unified mechanism 

that reconciles these features and embraces the two types of 

excitations as having a common origin. 

References 

[1] W. Bao, Y. Qiu, Q. Huang, M. A. Green, P. Zajdel, M. R. 

Fitzsimmons, M. Zhernenkov, S. Chang, M. Fang, B. Qian, E. K. 

Vehstedt, J. Yang, H. M. Pham, L. Spinu, and Z. Q. Mao, Phys. 

Rev. Lett. 102, 247001 (2009). 

[2] O. J. Lipscombe, G. F. Chen, C. Fang, T. G. Perring, D. L. 

Abernathy, A. D. Christianson, T. Egami, N. Wang, J. Hu, and P. 

Dai, Phys. Rev. Lett. 106, 057004 (2011). 

[3] M. D. Lumsden, A. D. Christianson, E. A. Goremychkin, S. E. 

Nagler, H. A. Mook, M. B. Stone, D. L. Abernathy, T. Guidi, G. 

J. MacDougall, C. de la Cruz, A. S. Sefat, M. A. McGuire, B. C. 

Sales and D. Mandrus, Nature Phys. 6, 182 (2010). 

Condensed Matter
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 27 
Condensed Matter
 

Correlation between spin-flop transition and 

enhanced spin polarized supercurrents in 

ferromagnetic Josephson junctions 

C. Klose1, T.S. Khaire1, Y. Wang1, W.P. Pratt1, N.O. Birge1, B. J. McMorran2,3, J. A. Borchers4, T. Ginley5, B.J. 

Kirby4

, B.B. Maranville4, J. Unguris2 

Production of spin-polarized superconducting currents 

(“supercurrents”) that can propagate over long distances 

opens up new possibilities for the development of 

low-energy, magnetoelectronic devices that combine 

magnetic storage and data manipulation with conventional

semiconductor electronics. Though the typical penetration depth 

of a superconducting current into a normal metal is on the order 

of microns, the Cooper pair correlations persist for only a few 

nanometers when a conventional, spin-singlet (i.e., zero total spin) 

superconductor is brought in contact with a strong ferromagnet.

Recent experiments, however, have demonstrated that the addition 

of magnetic inhomogeneities at the superconductor/ferromagnet 

interface give rise to a spin-polarized supercurrent with spin-triplet 

(i.e., total spin of one) symmetry that can be sustained over large 

lengthscales. In particular, research performed at Michigan State

University [1] focused on a multilayer Josephson junction with a 

central Cu/Co/Ru/Co/Cu block surrounded by thin ferromagnetic 

alloy (PdNi or CuNi) layers adjacent to the superconducting 

Nb electrodes at the top and bottom. The misalignment of the

ferromagnetic Co layers relative to the alloy layers was the source 

of the magnetic non-uniformity, and the Co sandwich also acted 

to suppress the spin-singlet current, even though it has no net 

magnetization due to the antiparallel alignment of the Co across 

the intervening Ru. The simple device design provided a means to

reproducibly create a spin-triplet supercurrent at low temperatures 

that can be easily tuned by changing parameters such as the 

thickness of the Co or alloy layers. 

More recent experiments on similar junctions revealed that the 

supercurrent can be enhanced by up to a factor of 20 simply by 

applying a large (> 0.1 T to 0.2 T), in-plane magnetic field [2]. 

Since misalignment of the ferromagnet magnetizations is crucial 

to the production of the spin-triplet state, the speculation was 

that the dramatic increase originates from a field-induced change 

in the magnetic configuration of the antiferromagneticallycoupled Co/Ru/Co sandwich in the junction center. To explore 

this enhancement we used the complementary techniques [2] 

of polarized neutron reflectivity (PNR) and scanning electron 

microscopy with polarization analysis (SEMPA) to characterize 

the magnetic structure of half junctions [Si substrate/Nb(150 

nm)/Cu(10 nm)/Co(X nm)/Ru(0.6 nm)/Co(X nm)/Cu(10 

nm)] before, during, and after applying magnetic fields of 

varying strength. PNR nondestructively probes the ensemble 

average of the net in-plane magnetization for each ferromagnetic 

layer, even in the presence of a field. When combined with ion 

milling, SEMPA images the remanent magnetization of the inplane domains within each ferromagnetic layer. Together these 

measurements revealed that the large magnetic field acts to flip 

a large fraction of the magnetization in the Co layers nearly 

perpendicular to the field and to the magnetizations of the thin 

alloy layers in the full Josephson junction. The local magnetic 

environment is thus more ideal for producing, sustaining and 

propagating the spin-polarized supercurrent. 

Several samples were examined for this study, and all showed 

qualitatively similar behavior. For illustration, we focus here on 

a sample with X = 6 nm that was characterized fully at room 

temperature before and after applying a 0.3 T field. In the 

PNR measurements performed on the NG-1 Reflectometer, 

the nonspin-flip cross sections (R++ and R−−) are sensitive 

to the nuclear structure as well as the projection of the net 

magnetization parallel to the guide field direction. The spin-flip 

cross sections (R−+ and R+−) originate solely from the projection 

of the total magnetization perpendicular to the field. The data 

were all fit (solid lines) using the REFL1D software package [3] 

in order to extract the depth-dependent structure and vector 

magnetization. 

Figures 1a and 1b show the PNR data for the as-grown sample, 

both upright (i.e., bare sample edge vertical) and rotated by 

approximately 90°, in a guide field of 0.003 T. For the upright 

configuration, the spin-flip cross sections in Fig. 1a are small, 

but nonzero, consistent with a slight canting of the Co layer 

magnetizations relative to the field. The R++ and R−− cross sections 

are dominated by structural scattering, but exhibit an unexpected 

splitting resulting from a small net magnetization along the guide 

field. In order to remove the structural scattering contribution, 

we rotated the sample relative to the guide field (Fig. 1b) in order 

to transfer the scattering from the magnetization component 

parallel to the bare edges from the non-spinflip to the spin-flip 

channels. The shape of the resultant spin-flip scattering is distinct 

and can only be reproduced by a model [3] with nearly perfect 

antiparallel alignment of the two Co layers. Simultaneous fits to 

the data in Figs. 1a and 1b reveal that the magnitude of the net 

magnetizations of the top and bottom Co layers are (822 ±25) 

1 Michigan State University; East Lansing, MI 48824 

2 Center for Nanoscale Science and Technology; National Institute of Standards and Technology; Gaithersburg, MD 20899 

3 University of Oregon; Eugene, OR 97403 

4 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg, MD 20899 

5 Juniata College; Huntingdon, PA 16652 

28 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

kA/m and (722 ±25) kA/m, respectively. The magnetization axes, 

shown in the schematics, are tilted at an angle of approximately 

25° relative to the sample edge, suggestive of a growth-induced 

anisotropy direction. 

FIGURE 1: PNR data and fits in a field of < 0 .002 T: (a) as-grown 

with sample upright, (b) as grown with sample rotated by 90°, 

(c) remanence after 0 .3 T field with sample upright and (d) with 

sample rotated by 90° . The arrows in the schematics (i.e., light blue 

designates bare sample edges) correspond to the average Co layer 

magnetizations . 

The PNR measurements were repeated in remanence after 

applying a 0.3 T field parallel to the bare edge of the sample. In 

this magnetic state, the spin flip scattering from the sample in 

the upright position (Fig. 1c) is more than double that obtained 

from the rotated sample (Fig. 1d). It is clear that the Co layer 

magnetizations have reoriented such that the majority of the 

moments are perpendicular to the field. Motivated by SEMPA 

results discussed below, these data were fit simultaneously with 

a model that includes an incoherent addition of scattering from 

two distinct domain states in which the antiparallel-aligned Co 

layers are rotated to either side of the applied field direction, 

as shown in the schematics. The magnetizations of the top and 

bottom Co layers in the dominant state are (381 ±20) kA/m 

and (273 ±20) kA/m, respectively, and the top and bottom 

layers in the secondary state have a reduced magnetization of 

(38 ±15) kA/m and (52 ±20) kA/m, respectively. Overall, the net 

magnetizations of each layer are significantly reduced from that 

obtained in the as-grown state indicating that a large fraction of 

the Co magnetization is distributed into in-plane domains with

dimensions smaller than the coherence length of the neutron 

beam (≈ 100 μm). 

SEMPA characterization of the same sample, both before and 

after application of the 0.3 T field, corroborated the PNR 

findings and provided specific details regarding the nature of 

the in-plane magnetic domains within each Co layer. For these 

measurements, images were obtained within a 1 mm2 window of 

the sample that was ion milled with 800 eV Ar ions to first reveal 

the top and bottom Co layer magnetizations sequentially. The 

corresponding images for the as-grown state are shown in Figs. 

2a and 2b, and the magnetization distribution in each image 

is summarized in the corresponding polar plot. The average 

directions of the layer magnetizations obtained from SEMPA 

match those obtained from PNR, confirming that the top and 

bottom Co layers are aligned antiparallel. The Co moments, 

however, are distributed about their average direction with an 

FIGURE 2: SEMPA images of the in-plane remanent magnetization in 

the top (a), (c) and bottom (b), (d) layers before (a), (b) and after (c), 

(d) a field of 0 .3 T . Polar histograms show the distribution (in grey) of 

magnetization angles in the image . The average magnetizations from 

the image (standard arrow) and from PNR (diamond-head arrow) are 

also shown . The magnitude of the small diamond-head arrows in (c) 

and (d), corresponding to the second domain state, has been scaled 

by a factor of 5 . 

angular spread of approximately 30°. After application of a 0.3 

T field, the angular spread of the in-plane moment distribution 

broadens substantially (Figs. 2c and 2d), with a bimodal domain 

distribution that is most pronounced in the top Co layer. Though 

the layer moments have now broken up into smaller domains, 

their average directions, which are consistent with those obtained 

from PNR measurements, are nearly perpendicular to the applied 

field. 

The field-dependent evolution of the magnetic structure was also 

characterized using PNR, since SEMPA can only be performed 

in residual fields. These data reveal that antiferromagnetic 

coupling between the Co layers persists in fields up to 

approximately 0.1 T at which point the moments form a 

scissors-like state symmetric about the applied field direction. 

The angle between the layer moments gradually decreases with 

increasing field. In remanence at high fields, both PNR and 

SEMPA (Figs. 1 and 2) indicate that the original antiparallel 

alignment between the Co layer moments is restored, but the 

original anisotropy direction is not recovered. Instead the high 

field induces a “spin flop” magnetic state, though with a broad 

distribution of in-plane magnetic domains. These investigations 

thus indicate that the spin-triplet supercurrent can be strongly 

enhanced by maximizing the misalignment between the 

magnetizations of the ferromagnetic outer and center layers 

in a Josephson junction. Full optimization of the polarized 

current in actual devices can potentially be achieved simply 

by tuning the competing magnetic interactions of the central 

antiferromagnetically-coupled sandwich. 

References 

[1] T.S. Khaire, M.A. Khasawneh, W.P. Pratt, N.O. Birge, Phys. Rev. 

Lett. 104, 137002 (2010). 

[2] C. Klose, T.S. Khaire, Y. Wang, W.P. Pratt, N.O. Birge, B.J. 

McMorran, T.P. Ginley, J.A. Borchers, B.J. Kirby, B.B. Maranville, 

and J. Unguris, Phys. Rev. Lett. 108, 127002 (2012). 

[3] 	P.A. Kienzle, J. Krycka, N. Patel, and I. Sahin, computer software 

REFL1D (Version 0.6.19), University of Maryland, 2011. Available 

from http://reflectometry.org/danse. 

Condensed Matter
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 29 
Condensed Matter
 

Charge ordering and magnetic frustration in the 

fluoride pyrochlore, RbFe2+Fe3+F6 

S.W. Kim,1 S-H. Kim,1 P.S. Halasyamani,1 M.A. Green,2,3 K.P. Bhatti,4 C. Leighton,4 H. Das,5 and C.J. Fennie5 

T

he discovery of new materials possessing magnetic 

frustration is essential to further our understanding of 

these complex magnets, which have future applications 

in the next generation of electronics. Oxide pyrochlores 

have played an important role in this goal, particularly with 

the discovery of “spin-ice” materials [1]. Fluoride pyrochlore 

have been less prominent, mainly as a result of problems with 

controlling stoichiometry; a key factor in studying model 

magnets. However, a new low temperature route to producing 

fluoride pyrochlore offers new opportunities to the field. In a 

recent paper, we have used neutron diffraction, combined with 

magnetization measurements and computational techniques, to 

study the properties of β-pyrochlore, RbFe2F6 [2]. 

Powder neutron diffraction measurements were performed 

on RbFe2F6 at several temperatures in the range, 4 K to 300 

K. RbFe2F6 crystallizes in the Pnma space group with lattice 

parameters of a = 7.02134(7) Å, b = 7.45093(7) Å and c = 

10.1795 (1) Å at room temperature. This represents a reduced 

orthorhombic cell of the conventional β-pyrochlore lattice 

with the Fd-3m symmetry. It is related to the more common 

α-pyrochlore lattice, with the general formula, A2B2X6X’, through 

two ordered vacancies. Firstly, one of the two A cations is vacant, 

which reverts the kagome network of the A sites in α-pyrochlore 

into a diamond lattice with Td point symmetry. Secondly, the 

anion, X’, that does not contribute to the BX6 octahedra is vacant; 

removing this apical anion reduces the 8 coordination of the A 

cation and leaves an open cage site (see Fig. 1). 

FIGURE 1: (a) α-pyrochlore has a A2X’ network that is simple A in the (b) β-pyrochlore . 

1 University of Houston; Houston, TX, 77204-5003 

2 University of Maryland; College Park, MD, 20742-2115 

3 NIST Center for Neutron Research; National Institute of Standards and Technology;Gaithersburg, MD, 20899-6103 

4 University of Minnesota; Minneapolis, MN, 55455 

5 Cornell University; Ithaca, NY, 14853 

30 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
One key feature of β-pyrochlores that has greatly hindered their 

usefulness as model magnetic systems is their tendency for both 

site disorder and partial occupancy. To evaluate these possibilities 

a number of models were tested and no evidence could be found 

for such issues in RbFe2F6. 

FIGURE 2: Lattice parameters of RbFe2F6 as a function of temperature . 

Figure 2 shows the lattice parameters as a function of 

temperature. All three lattice parameters show a modest 

contraction down to the magnetic ordering temperature, below 

which there is negative thermal expansion, particularly within the 

ab plane. No structural phase transition was found on cooling 

and RbFe2F6 remained orthorhombic with Pnma symmetry to 

the lowest temperature measured. One central structural feature 

was the difference between thermal factors of the constituent 

elements. 

Condensed Matter 

FIGURE 3: Thermal parameters for RbFe2F6 . 

Figure 3 shows the isotropic thermal factor for all 6 atoms as 

a function of temperature. Although each atom has a typical 

temperature dependence, the absolute value of U for Rb is ≈ 5 

times that of the lighter Fe, and even twice that of F that is over 

four times lighter. The rattling effect of A site cations within 

the β-pyrochlores is well documented and results from a gross 

mismatch between the ionic radii of the cations and the space 

available. 

A new charge-ordered magnetically frustrated mixed-metal 

fluoride with a pyrochlore-related structure has been synthesized 

and characterized. The material,exhibits a three-dimensional 

pyrochlore-related structure consisting of corner-shared Fe2+F6 

and Fe3+ 

6 octahedra. Magnetization measurements reveal strong 

antiferromagnetic interactions (a Curie-Weiss temperature of 

-270 K) but the structure is sufficiently frustrated to suppress 

long range ordering until 16 K. 

References 

[1] M.J. Harris, S.T. Bramwell, D.F. McMorrow, T. Zeiske and 

K.W. Godfrey, Phys. Rev. Lett. 79, 2554 (1997). 

[2] S.W. Kim, S.H. Kim, P. S. Halasyamani, M.A. Green, K.P. 

Bhatti, C. Leighton, H. Das, and C.J. Fennie Chemical Science 

3, 741 (2012). 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 31 
 

Engineering

Measuring yield stresses in biaxial deformation
 

T. Gnäupel-Herold1,2, T. Foecke3, A. Creuziger3, M. Iadicola3 

,

 L. Hu4 

S

heet metal forming is a tricky business even after a 

century of mass production typical for the automotive 

industry. This is in good part due to the difficulties in 

predicting springback. Everyone who has ever bent a 

long, thin piece of metal is familiar with the phenomenon – the 

metal piece springs back after releasing the applied force. The 

amount of this ‘springback’ at the release of the stamping tool 

must be known precisely if doors, hoods and handles are to 

fit together. Predicting the magnitude of springback for such 

complex shapes has proven to be a lasting challenge because of 

the side effects of automotive light weighting – thinner gages 

at higher strength (high strength steels) and lighter materials 

(aluminum and magnesium alloys), all of which strongly increase 

springback. Contrary to expectation, the poor predictability 

is caused less by a lack in computing power for running finite 

element codes than by insufficient knowledge of the materials 

constants that govern multi-axial straining, not just of advanced 

steels but almost any structural material. The measurement 

of these constants, called the yield stresses, is described in the 

following. 

The key in obtaining these much needed properties is the 

measurement of plastic strains and stresses while the material 

is being deformed. Stress can only be determined through the 

elastic strains it causes. This requires three steps: (1) the capability 

for biaxial deformation with a prescribed strain by applying 

a (unknown) stress; (2) in situ measurement of lattice strains 

during forming and (3) the conversion of the thus measured 

lattice strains into the previously unknown stresses applied in 

step (1). The key fact to know is that diffraction only measures 

lattice strains which represent the elastic part of the strains from 

which the stresses can be obtained – if the elastic constants are 

known. The combination of the technologies in (1) and (2) have 

been implemented over the past decade at NIST. Plastic strains 

are measured during straining using digital image correlation 

with precisions of ≈ 10-3. The measurement of elastic strains 

needed to determine stress needs a precision at least one order of 

magnitude better (≈ 5x10-5) which is realized through an x-ray 

diffractometer integrated into the forming machine for in situ 

measurements. Using established analysis methods, a proof-ofconcept was delivered through the measurement of the yield 

surface of an aluminum alloy. However, advancing this concept 

FIGURE 1: Left: d-spacings as measured for different stresses; 

right: lattice strains for fixed directions y and different stresses 

(1:sin2y = 0, 2: sin2y = 0 .18, 3: sin2y = 0 .5) . The color code 

in the legend applies to both graphs; empty symbols are for 

stresses not shown on the left graph . Strains are referenced 

to the green curve on the left, thus, all strains are zero at zero 

stress . Without elastic anisotropy, each curve on the left would 

be a straight line; without intergranular strains, the green curve 

at zero stress would be flat . Intergranular strains are dealt with 

by referencing to the zero-stress d-spacings, elastic anisotropy 

requires measurement of elastic constants in each direction 

(the slopes in the linear regressions on the right) . 

to steels has proven to be challenging because of its strongly nonlinear behavior caused by large elastic anisotropy (Fig. 1). 

The challenge to the data analysis is to reproduce the d-spacings 

in Fig. 1, left, for known stresses. However, the comparison of 

results from modeling of diffraction elastic constants (DEC) with 

neutron diffraction measurements has shown that at this point 

no model is able to predict with sufficient accuracy the evolution 

of DEC with texture and grain shape. This includes advanced 

models that use quantitative texture information from neutron 

diffraction together with grain-morphology data. Only the use of 

measured DEC produced satisfactory agreement between known 

and calculated stresses while also allowing a statement of accuracy 

of the measurement rather than its precision. For example, the 

use of measured DECs gave average accuracies ≈ 2 % while the 

best model yielded accuracies ≥ 10 %. With the scale clearly 

tilting in favor of an all-around measurement of DEC, the 

question remains how many DEC measurements are necessary 

before the actual quantities of interest – the flow stresses - can 

be determined. Typically, during sample deformation the plastic 

straining is halted 10 to 15 times for the x-ray measurements of 

lattice strain. If elastic constants were to be measured for each 

level of plastic strain it would require 10 000+ measurements 

to completely characterize a material. This is clearly prohibitive, 

1

 University of Maryland; College Park, MD 20704 

2

 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg, MD 20899-6102 

3

 NIST Metallurgy Division; National Institute of Standards and Technology; Gaithersburg, MD 20899 

4

 Carnegie Mellon University; Pittsburgh, PA 15213 

32 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

and for that reason a hybrid method was developed in which 

a more limited set of measured DEC is used to fit a function 

that approximates the theoretical evolution of the DEC with 

plastic strain. Plastic deformation occurs through slip and grain 

rotation, both of which affect the DEC through changes of 

morphology and orientation of grains. The evolution of DEC 

with plastic strain is simulated first through a visco-plastic selfconsistent (VPSC) crystal plasticity model which puts out the 

grain orientation distribution function (ODF) for a given level of 

plastic strain. Second, DEC are calculated from a grain-aggregate 

interaction model that uses the ODF to simulate the behavior of 

the polycrystal. The simulations confirm the expectation that in 

materials without stress-induced phase transformations texture 

and texture-derived properties change with strain in a monotonic 

fashion. The precise nature of this strain-property correlation 

cannot be established as a closed-form expression because the 

entire model is far too complex to be reduced analytically in this 

way; it must be approximated itself by a fit. It was found that 

the crystal-elastic behavior reflected in the DEC is described 

better by a linear correlation than by a type of power law that can 

inferred from the uniaxial stress-strain behavior of the aggregate 

(Fig. 2, green curve). 

FIGURE 2: Dependence of diffraction elastic constants on 

plastic strain for one orientation of the scattering vector . 

The blue and green curves are simulated but each data point 

in the blue was obtained from a DEC model together with 

an ODF from three measured neutron diffraction pole 

figures . Each data point in the red curve represents the linear 

regression of five measurements (elastic) lattice strain vs 

applied stress (see Fig . 1) . 

A comparison between measured and simulated DEC for a 

multitude of directions and plastic strains has shown that the 

quantitative agreement between the DEC is generally not 

sufficient for an all-around use of calculated DEC for stress 

determination. Instead, a first-order polynomial is fitted to 

the measured DEC for each direction and each strain level. 

This procedure solves the problem to obtain DEC at plastic 

strains where DEC have not been measured with the useful 

side effect that the overall uncertainties are somewhat reduced 

(Fig. 3: s ≈ 10 MPa). The final result, obtained from (stress = 

DEC x strain), is shown in Fig. 3 which represents the first-ever 

measured biaxial yield stresses for steel using diffraction. Figure 3 

shows summarily the steps that are necessary in order to obtain 

biaxial yield stresses: from lattice strains measured during plastic 

straining to measurements of diffraction elastic constants (DEC) 

done on pre-strained samples but under elastic loading. The 

recognition that, through texture, DEC evolve in a nearly linear 

fashion with plastic strain is the basis for a procedure that allows 

us to obtain stresses at any of the intermediate plastic strains in 

Fig. 3, bottom. 

FIGURE 3: General outline of the procedure to measure biaxial yield stresses . Lattice strains are measured at an unknown 

biaxial stress (top,left), with unknown elastic constants . 

Diffraction elastic constants (DEC) are measured on separate 

samples that were extracted at pre-defined plastic strains 

(top, right) . Both lattice strains and DEC together allow the 

determination of the stresses shown in the lower graph . 

References 

[1] T. Gnäupel-Herold, A. Creuziger, M. Iadicola, J. Appl. Cryst. 

45, 197 (2012). 

Engineering

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 33 
 

 

 

A new limit on time-reversal violation in beta decay
 

H. P. Mumm1, T. E. Chupp2, R. L.Cooper2, K. P. Coulter2, S. J. Freedman3, B. K. Fujikawa3, A. Garcia4, G. L. Jones5, J. 

S. Nico1

, A. K. Thompson1, C. A. Trull6, J. F. Wilkerson6, and F. E. Wietfeldt7

Neutron Physics
 

T

he stars and galaxies that make up our universe can 

only form if, during the initial moments after the Big 

Bang, there existed a slight dominance of matter over 

antimatter. It has been understood for some time that 



p ) (i.e., involving e 

however in the neutron rest frame, the triple correlation from •  Eq. 1 can be expressed as Dsn (p 

p x 

protons and electrons). Thus, one can extract D from the spin 

dependence of proton-electron coincidences in the decay of cold 

such an imbalance can only be explained if three conditions 

are met; a departure from thermal equilibrium, a violation 

of baryon (i.e., three quark states) number, and a violation of 

charge-conjugation-parity (CP) symmetry in the physical laws 

that govern particle interactions (charge conjugation turns 

particle states into the corresponding anti-particle states and 

parity is essentially a mirror reflection of the state). Thus far, CP 

violation has been observed only in the K and B meson systems 

(i.e., quark-antiquark states) and can be entirely accounted for 

within the Standard Model of particle physics (SM). However, 

the extent of SM CP violation is many orders of magnitude too 

small to account for the known asymmetry in the context of Big 

Bang cosmology, so there is compelling reason to search for CP 

violation in other systems. As CP and Time-reversal symmetry 

(T) violation can be theoretically related to one another, 



experimental limits on T-odd observables in nuclear beta decay 

place strict constraints on possible sources of new CP violation. 

We have recently reported the results of an improved experiment 

that limits time-reversal invariance violation in the beta decay 

of polarized neutrons and thus constrains extensions to the 

Standard Model. 



The decay probability distribution for neutron beta decay, 

dW, can be written in terms of the neutron spin-state σ

pe

polarized neutrons. 

FIGURE 1: A schematic of the emiT detector illustrating the alternating 

electron and proton detector segments The shaded detectors show the 

example of the paired-ring at z ±10 cm The cross section view illustrates, 

in a greatly exaggerated manner, the effect of the magnetic field on the 

particle trajectories A P2

E2 coincidence event is shown

Our measurement was carried out at the NCNR NG-6 beamline. 

The detector, shown schematically in Fig 1, was built to be highly 

symmetric and consisted of an octagonal array of four electrondetection planes and four proton-detection planes concentric 

with the longitudinally polarized beam. The beam, with a 

neutron capture fluence rate at the detector of 1.7 x 108

 cm-2 s-1 , 

was polarized to > 91 % (95 % C.L.) by a double-sided bendertype supermirror. A 0.56 mT (5.6 G) guide field maintained 

the polarization direction, while a current-sheet spin-flipper was 

used to periodically reverse the neutron spin direction, allowing 

 n, the 

(Ee) and antineutrino pv for first order cancellation of detector efficiency variations. The 

octagonal geometry was chosen to maximize sensitivity to D, and momenta (energy) of the electron (Ev) 

as [1]  the highly symmetric arrangement allows for the approximate p e • 

p v + b 

EeEv Ee 

 p p p 

e 

+ B v + D 

Ee Ev EeEv 

 x p m  e v σ e dW ∝ 1+ a + A 
 n • .
 (1) cancellation of systematic effects stemming from residual 

coupling to the relatively large spin-correlations A and B (≈ 0.1 

A contribution of the parity-even (P-even) triple correlation and ≈ 1 respectively) in Eq.1. Each of the four proton segments 

D above the level of calculable final-state interactions (FSI) consisted of a 2 x 8 array of silicon surface-barrier diode detectors 

unambiguously indicates a violation of T symmetry. While the (SBDs). Because the maximum proton energy from the decay 

FSI for the neutron are ≈ 1x10-5, previous D measurements is very low, approximately 750 eV, protons were accelerated 

had reached ≈ 7x10-4 [2]. Thus, improved measurements of through grounded wire-mesh boxes and onto SBDs mounted 

D probe non-SM sources of T-violation. Various theoretical within an electrode normally held between -25 kV and -32 kV. 

models that extend the SM, such as left-right symmetric theories, The beta detectors were slabs of plastic scintillator with sufficient 

leptoquarks, and certain exotic fermions could cause observable thickness to stop electrons at the decay endpoint energy of 782 

effects that are as large as the present experimental limits [3]. In keV. Scintillation photons were detected by photomultiplier 

small-scale experiments the neutrino is effectively unobservable, tubes (PMTs) at each end of the slab. Details of the apparatus 

can be found elsewhere [4]. 

1 National Institute of Standards and Technology; Gaithersburg, MD 20899 

2 University of Michigan; Ann Arbor, MI 48104 

3 University of California at Berkeley and ; Lawrence Berkeley National Laboratory,; Berkeley, CA 94720 

4 University of Washington; Seattle, WA 98195 

5 Hamilton College ; Clinton, NY 13323 

6 Tulane University ; New Orleans, LA 70118 

7 University of North Carolina; Chapel Hill, NC 27599 

34 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

 

 

 

 

FIGURE 2: Log plot of SBD-scintillator coincidence data showing proton 

energy vs delay time Events near Δt

 = 0 are prompt coincidences due 

primarily to beam-related backgrounds . 

Neutrons have a relatively long lifetime of 881 s, thus, even with 

a high fluence beam and a very efficient detector, the typical 

count rate for the entire array was only 25 s-1 . After various 

instrumental cuts were applied to improve data quality, the final 

data set, taken over roughly one year of running, consisted of 

approximately 300 million coincidence events. These events 

were divided into two timing windows based on the proton 

time-of-flight, a pre-prompt window, and the decay window, as 

shown in Fig. 2 (The recoil proton is delayed by approximately 

0.5 μs on average). The pre-prompt background was subtracted 

from the spectrum in the decay window. Because of the 

tight coincidence requirement in time, the average signal-tobackground was excellent, approximately 30/1. Integrating these 

energy spectra then gives the total number of decay events for 

a particular proton-detector electron-detector pair. A non-zero 

D would manifest itself as a slight asymmetry in the number of 

coincidence events seen between a given proton-detector and the 

two opposing electron detectors, i.e., P2E2 and P2E1 in Fig. 1. To 

extract D, coincident events are first combined in approximately 

efficiency-independent asymmetries 

N p

i ej 

- N p

i ej p

i ej ­ w = p

+ p , (2) i e

j N+ i ej - Nwhere N+ 

p

i ej

 is the integrated number of coincident events in 

proton detector pi , beta detector ej , with neutron spin + (-) 

aligned (anti-aligned) with the field. For a uniform polarization 

vector, P, 



the w can be written in terms of decay correlations as     p

i ej pi ej w ≈ P• AK pi ej + BK pi ej + DKD 

where the K



 vectors are obtaine

A

d from E

B

q. 1 by integrating 

each term over the phase space of the decay, the neutron beam 

volume, and the acceptance of the indicated detectors. As 

K



B and KA are proportional to 〈pv /Ev〉 and 〈pe /Ee〉 respectively, 

both have small longitudinal components and thus the parityviolating correlations A and B in Eq. 2 lead to a w at the level 

of 1x10-3, an order of magnitude larger than the desired 

sensitivity. Fortunately, one can choose appropriate 

combinations of detectors that are sensitive to the D-correlation 

but that largely cancel the effect of A and B. One such 

combination is v p

i = 1⁄2(wp

iR – wpiL) where R and L label the 

electron-detector at approximately 135° giving a positive and 

negative cross-product pp x p



e respectively (P2E2 vs P2E1 as shown 

in Fig. 1). We define v as the average of the values of v from the 

sixteen proton-cells at the same z, i.e., (±2, ±6, ±10, and ±14) 

cm. Each set corresponds to paired-rings with the same symmetry 

as the full detector; the shaded detectors in Fig. 1. We then obtain 

v = P K

DD, where K



D is determined by a Monte Carlo calculation, 

and the experiment provides four independent measurements of 

D corresponding to the four paired-rings. 

Systematic effects fall into two categories; those that change 

the sensitivity to D, and those that result in a false asymmetry. 

Variations in flux, polarization, spin-flip frequency, and 

uncertainty in the constant K



D, can be shown to produce 

asymmetries proportional to D. Due to the high signal-tonoise, errors in background subtraction, as well as possible spindependent asymmetries in this background, have a negligible 

effect. Other effects alter the symmetry of the detector and can 

therefore lead to a false asymmetry. For example, proton 

detector efficiencies were not uniform due to lower energy 

thresholds that varied slightly across the detector. The thresholds 

combined with the spin-dependence of the accelerated proton 

energy spectra resulted in a significant, but measureable, error 

in w. Beam expansion from a radius of ≈ 2.5 cm to ≈ 2.75 cm 

combined with the weak magnetic field also breaks the detector 

symmetry because the average proton-electron opening angle 

for each detector pair is modified. Monte Carlo calculations 

using measured density profile maps were used to calculate a 

correction. Finally, for a symmetric beam, contributions to v due 

to transverse components of the polarization cancel for opposing 

paddles; however small azimuthal beam asymmetries on the 

order of even millimeters affect this cancellation. To study this 

effect transverse-polarization calibration runs were taken over the 

course of the experiment. In these runs the effect was amplified 

by ≈ 200. The false D from the transverse runs was then scaled 

to the observed polarization misalignment. Other effects of 

polarization non-uniformity are small. Finally, a blind analysis 

was performed by adding a constant hidden factor to Eq. 2. that 

was only removed once all analyses of systematic effects were 

complete. 

The final result, including all corrections, is D = (-0.96 ± 1.89 

(stat) ± 1.01 (sys)) x 10-4 [5,6]. Prior to this measurement, 

the most sensitive measurement of D was in 19Ne, with D = 1 

± 6 x 10-4 [7]. Thus, our result represents the most sensitive 

measurement of the D-coefficient in nuclear β-decay and 

improves constraints on CP-violation in leptoquark and certain 

exotic fermion extensions to the SM. 

References 

[1] J.D. Jackson, S.B. Treiman and H.W Wyld, Jr., Phys. Rev. 106, 517 

(1957). 

[2] T. Soldner, et al., Phys. Lett. B, 581, 49 (2004). 

[3] P. Herczeg, Proc. of the 6th Int. PASCOS-98, World Scientific, 

Singapore, (1998). 

[4] H.P. Mumm, et al., Rev. Sci. Instrum. 75, 5343 (2004). 

[5] H.P. Mumm, et al., Phys. Rev. Lett. 107, 102301 (2011). 

[6] T.E. Chupp, et al., Phys. Rev. C, 86, 035505 (2012). 

[7] F. Calaprice, Hyperfine Interactions, Springer, Netherlands 22, 83 (1985). 

Neutron Physics
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 35 
Soft Matter
 

Self-assembling organohydrogels: liquid 

dispersions with solid-like behavior 

M.E. Helgeson1, S.E. Moran2, H.Z. An2, P.S. Doyle2 

Gels comprised almost entirely of water (hydrogels) or 

oil (organogels) have become important to a number 

technologies that take advantage of their combined 

liquid-like transport and solid-like mechanical 

properties. However, the ability to create gels containing both 

water and oil, allowing encapsulation and transport of both 

polar and non-polar solutes, could lead to significant advances in 

these applications. 

We recently discovered a novel class of such “organohydrogels” 

based on oil-in-water nanoemulsions [1]. These nanoemulsions 

are metastable liquid dispersions typically formed from highenergy processing techniques [2]. The nanoemulsions contain 

four primary components – water, silicone oil, a surfactant 

stabilizer, and poly(ethylene glycol) diacrylate (PEGDA) – and 

exhibit the ability to reversibly self-assemble from a low-viscosity 

liquid to a gel over a narrow range of temperature (Fig. 1). The 

small-strain mechanical properties of these materials resemble 

those of a linear elastic solid, with elastic (Gʹ) and viscous 

(Gʹʹ) moduli that are nearly independent of the applied rate of 

deformation. This is remarkable, given that the organohydrogels 

form with compositions up to 90 % oil and water. 

FIGURE 1: Linear viscoelastic moduli, G’ (closed symbols) and G’’ (open 

symbols), of a nanoemulsion containing 33 % oil droplets (radius = 17 

nm) in 44 % D2O and 22 % PEGDA undergoing a transition from a lowviscosity liquid to a highly elastic solid at high temperatures (see also 

inset photographs) . Inset plot shows linear viscoelastic spectra of the 

sample through the gel transition . 

To understand the mechanisms of self-assembly and solid-like 

behavior in these new materials, we used SANS and USANS to 

characterize the microstructure and interactions of the gelling 

nanoemulsions. In particular, the use of contrast variation 

allowed us to independently interrogate the behavior of the 

different material constituents. First, we performed SANS 

on dilute nanoemulsions in aqueous PEGDA solutions over 

temperatures spanning well below and above the gel transition 

(Fig. 2). The low-q scattering, dominated by the nanoemulsion 

droplets, shows a significant increase in intensity with 

temperature, indicating changes in interdroplet interactions. 

Furthermore, increases in high-q scattering, dominated by 

PEGDA, with increasing temperature suggest self-association 

of PEGDA in solution. Separate measurements of the polymer 

conformation in solution show no significant changes in 

solvent quality during this process [1], indicating that PEGDA 

association is primarily driven by the functional end-groups, 

as shown previously for other chemistries [3]. The overall 

scattering of the dilute nanoemulsions was fit to a combined 

model including both the polymer conformation and square-well 

interdroplet attractions, revealing an abrupt transition in the 

attractive well depth near the gel transition temperature (Fig. 2). 

FIGURE 2: (Left) SANS spectra from nanoemulsion containing 1 % oil 

droplets (radius = 17 nm) in 44 % D2O and 22 % PEGDA for temperatures 

spanning the gel transition, indicating interdroplet attractions 

mediated by polymer end-group solubility . (Right) Combined SANS/ 

USANS spectra from a nanoemulsion containing 33 % oil droplets 

(radius = 17 nm) in 44 % polymer matching solvent (82/18 H2O/D2O) 

and 22 % PEGDA . 

These results suggest that formation of the organohydrogels is 

driven by changes in polymer-mediated interdroplet attractions. 

Specifically, we hypothesize that the moderately hydrophobic 

polymer end-groups are driven to the oil-water interface at 

elevated temperatures, resulting in interdroplet bridging of 

the polymer (Fig. 2). This was corroborated by rheological 

measurements of the dependence of gel formation on the 

polymer chemistry, in which both the gel temperature and 

modulus were found to vary significantly according to the 

hydrophobic character of the polymer end-groups [1]. 

1 University of California, Santa Barbara, Santa Barbara, CA 93106 

2 Massachusetts Institute of Technology, Cambridge, MA 02139 

36 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
SANS and USANS measurements were then performed on 

more concentrated nanoemulsions where thermogelation 

occurs in order to elucidate the organohydrogels’ microstructure 

(Fig. 2). These experiments were made under solvent conditions 

in which PEGDA was contrast-matched to specifically isolate 

the droplet microstructure. At low temperatures, the scattering 

is indicative of a well-dispersed droplet suspension, and is in 

quantitative agreement with that predicted from the dilute 

droplet interactions. 

Above the gel temperature, no changes in high-q scattering 

occur, indicating that spherical droplets remain upon gelation, 

and do not fuse or transform into other morphologies. By 

contrast, significant increases in low-q scattering are observed, 

indicating the formation of large droplet aggregates. The powerlaw dependence of the scattered intensity at moderate q-values 

indicates fractal droplet clusters, much like those found in hard 

sphere colloidal gels [4]. The slope of -3.4 indicates dense clusters 

with a combination of mass and surface fractal contributions. 

Furthermore, a shoulder in the scattering at low q-values 

indicates limited cluster growth. We believe this limited growth 

is due to arrested phase separation of the droplets, whereby the 

q-value of the associated shoulder marks a characteristic length 

scale of droplet-lean “pores”, as has been predicted for attractive 

near-hard sphere colloidal gels [5]. 

From this, we surmise that the solid-like behavior of the gels 

arises from the effective “bonds” between dense droplet clusters 

mediated at the molecular level by the polymer-induced 

interdroplet attractions (Fig. 2). Thus, the gel strength can be 

enhanced through the use of a polymer with more hydrophobic 

end-groups, thereby increasing polymer bridging and the 

cluster bond strength [1]. In this regard, the elasticity of the 

nanoemulsion gels is very similar to that of hard particle colloidal 

gels, but where the polymer self-assembly provides a convenient 

route for controlling the gelation process. 

The ability to make self-assembled structures such as 

organohydrogels permanent can be critical for their processing 

and end use. Here, this is achieved by photoinitiated free radical 

polymerization of PEGDA to form a crosslinked polymer 

network in the aqueous phase, providing encapsulation of the 

nanoemulsion in a semi-permanent matrix. Contrast variation 

SANS and USANS measurements were thus used as a critical test 

of the ability to “freeze” targeted droplet microstructures within a 

polymer network (Fig. 3). Nanoemulsions in a polymer contrastmatched solvent were photocrosslinked at temperatures both 

below and above the gel transition. These samples (Fig. 3) exhibit 

scattering that is nearly identical to that before crosslinking 

(Fig. 2), indicating that both well-dispersed and gelled droplet 

microstructures can be successfully encapsulated. 

Soft Matter 

FIGURE 3: Combined SANS/USANS spectra from crosslinkable 

nanoemulsions . A nanoemulsion photocrosslinked above the 

gel temperature (red) exhibits similar droplet microstructure 

at temperatures both above (open) and below (closed) the gel 

temperature, whereas a nanoemulsion photocrosslinked below the 

gel temperature (blue) exhibits changes in droplet microstructure 

between the same temperatures (see insets at right) . 

The temperature of the samples crosslinked below and above the 

gel transition, respectively, was then switched to the opposite end 

of the gel transition in order to test whether the encapsulated 

droplet microstructures remained intact. Interestingly, we 

find that while emulsions crosslinked above the gel transition 

temperature retain their percolated cluster microstructure, those 

crosslinked below the transition temperature exhibit increased 

low-q scattering at elevated temperatures, suggesting limited 

ability of the droplets to form clusters in spite of the large steric 

barrier to self-assembly provided by the crosslinked polymer 

network. These composites exhibited significantly different 

strains required to break the material [1], suggesting that droplet 

microstructure is a key parameter governing the mechanical 

properties of such composites. 

In summation, we have presented a fascinating new class of 

solid-like gels from entirely liquid dispersions. Our neutron 

scattering measurements give critical insight into the mechanisms 

of thermoreversible gel formation and elasticity. These results 

will motivate predictive multi-scale models that capture the 

interdependence of polymer self-assembly and gel formation, 

providing means by which to rationally engineer the structure 

and properties of organohydrogels at the molecular level. 

Furthermore, the ability to “freeze” the nanoemulsion into a 

crosslinked polymer gel provides new ways by which to create 

soft nanocomposites with highly controlled microstructure. 

References 

[1]	 M.E. Helgeson, S.E. Moran, H.Z. An, P.S. Doyle, Nature Materials 11, 

344 (2012). 

[2]	 T.G. Mason, J.N. Wilking, K. Meleson, C.B. Chang, S.M. Graves, J. 

Phys.: Condensed Matter 18, R635 (2006). 

[3]	 B. Hammouda, D.L. Ho, S. Kline, Macromolecules 37, 6932 (2004). 

[4]	 H. Wu, J.J. Xie, M. Lattuada, M. Morbidelli, Langmuir 21, 3291 (2005). 

[5]	 E. Zaccarelli, J. Phys.: Condensed Matter 19, (2007). 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 37 
 

 

Soft Matter
 

Thickness fluctuations in model membranes
 

A.C. Woodka1, P.D. Butler1,2, L. Porcar3, B. Farago3, M. Nagao1,4 

Biological membranes are complex structures whose role 

is to provide selective permeability: allowing necessary 

nutrients in while excluding toxins, and allowing waste 

to exit while preventing vital intracellular components 

from escaping. The highly dynamic nature of these membranes 

plays a critical role in maintaining this delicate balance. 

These motions range from individual lipid oscillation, to the 

undulation of large (micron size) patches of the membrane. At 

atomic to molecular length scales the diffusion of individual 

lipids within the membrane have been shown to affect cell signal 

transduction while at the large length scales membrane stiffness 

and fluidity have been shown to have a significant impact on 

cellular uptake and release. The dynamics at intermediate length 

scales are collective movements of dozens of molecules, and 

thus, fundamental to understanding how the large scale motions 

emerge from atomic and molecular movements and interactions, 

yet remain experimentally elusive. At this intermediate length 

scale thickness fluctuations have been suggested theoretically and 

even proposed as a mechanism for membrane pore formation. 

In the study highlighted here, we use Neutron Spin Echo 


Spectroscopy (NSE) to probe the thickness fluctuations in 


lipid membranes [1]. We report the experimentally measured 


thickness fluctuations in a single component phospholipid 


model membrane as a function of both lipid tail length and 


temperature. Unilamellar vesicles (ULVs) composed of a single 


lipid dimyristoyl-, dipalmitoyl-, or distearoyl-phosphocholine 


(DMPC = 14 carbon tail, DPPC = 16 carbons, or DSPC =18 


carbons) were prepared and their dynamics characterized using 


NSE complemented with Small Angle Neutron Scattering 


(SANS) to fully characterize each system.
 

In order to highlight the thickness fluctuations, tail deuterated 

and fully hydrogenated lipids were mixed in an appropriate ratio 

so that the membrane tail region was contrast-matched with 

D2O. Saturated phosphocholine lipids undergo a first order 

phase transition known as the melting transition at temperature 

Tm, resulting in a change in membrane thickness and density. 

Tm was determined for each lipid to be 20.5 oC, 37.5 oC, and 

50.5 oC (± 0.2 oC) for our DMPC, DPPC, and DSPC systems, 

respectively, using densitometry. Relatively monodisperse 100 nm 

lipid vesicles were prepared by heating each lipid solution above 

Tm and extruding through a polycarbonate filter. 

Initially SANS is measured to determine membrane thickness. 

Figure 1a shows the SANS from DPPC ULVs at 30 oC, 40 oC, 

and 50 oC. The scattering from the bilayer is modeled as vesicles 

with a Schulz distribution of radii and composed of three layers, 

each with a corresponding scattering length density (SLD). The 

two outer layers of the membrane represent the hydrogenated 

lipid headgroup regions and were constrained to have equal 

thickness and SLD, the third (center) layer represents the 

contrast matched deuterated lipid tail region. The lines in Fig. 

1a represent the vesicle fits. The change in membrane thickness, 

dm, on crossing Tm is clearly visible in the shift of the SANS dip 

position, qmin. 

The normalized intermediate scattering functions, I(q,t)/I(q,0), 

for each lipid were measured by NSE (see Fig. 1b). Since the 

single membrane undulational motion is the primary dynamic in 

the present system, the theory of Zilman and Granek [2] for the 

bending motion of a single membrane should be applicable as: 

I(q,t) = exp[-(Γt)

2/3], (1) I(q,0) 

where Γ is the decay rate which scales as q3 

. 

The data for the fluid phase (above Tm) of each lipid system 

shown in Fig. 1c, d, and e (DMPC, DPPC, and DSPC 

respectively) clearly exhibit a deviation from the expected q3 

behavior. This excess in dynamics is observed as a peak in Γ/q3

 at 

the qmin observed in the SANS measurement (DPPC shown in 

Fig. 1a) indicating that the length scale of the enhancement in 

the dynamics signal is that of the membrane thickness and thus 

due to membrane thickness fluctuations. In the gel phase (below 

Tm) the lipid tails are much more ordered leading to a much 

more rigid membrane which translates into the much smaller Γ

observed here. Interestingly, in this regime there is no observable 

excess in the dynamics (no peak in Γ/q3

). 

In order to further characterize the excess in dynamics at the 

membrane thickness length scale, we assume that the decay 

rate contains two additive terms and can be expressed by the 

following empirical equation: 

, (2) 

1 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg, MD 20899-6102 

2 University of Delaware; Newark, DE 19716 

3 Institut Laue Langevin; Grenoble Cedex 9, FRANCE 

4 Indiana University; Bloomington, IN 47408 

38 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
FIGURE 1: (a) Temperature variation SANS of DPPC vesicles . Vertical 

lines represent qmin, fits are to the three shell vesicle model described 

in the text . (b) I(q,t)/I(q,0) of DPPC vesicles at T = 50 oC, fits are to Eq . 1 . 

q-dependence of Г/q3

 for (c) DMPC (d) DPPC and (e) DSPC vesicles, fits 

above T m are to Eq . 2 . Error bars represent ±1 standard deviation . 

where the first term represents the bending fluctuations. κ

and ηD are bending modulus and solvent viscosity, and ΓTF 20

represents the decay rate due to the thickness fluctuations leading 

to the excess dynamics observed at q = q0. ΓTF/q0 

3

 is the peak 

height of the Lorentzian where q0 is the peak position of the 

Lorentz function, and ξ-1 is the width of the Lorentzian. Here 

η and k T are known quantities and q comes from the SANS D20 B 0

measurements. κ is plotted in Fig. 2a as a function of the reduced 

temperature, T-Tm. The expected transition in κ as Tm is crossed 

is clearly visible and agrees well with literature values within the 

uncertainty of our measurements. 

The temperature dependence of the thickness fluctuation 

decay rates, ГTF, is shown in Fig. 2b. Within our experimental 

uncertainty these rates appear independent of either lipid tail 

length or temperature above Tm. The computed relaxation time, 

FIGURE 2: (a) The bending modulus, κ, (b) relaxation rate, ГTF, 

and (c) amplitude of thickness fluctuations, d m ξ-1

/q0, plotted 

against the reduced temperature, T-T m . 

τ = 1/ГTF, is on the order of 100 ns, which is much smaller 

than those found in surfactant membrane systems (which are 

only a few ns) [3]. Such a significant slowdown of thickness 

fluctuation might originate from larger membrane viscosities, 

increased membrane stiffness, or differences in compressibility of 

membranes. One explanation for the lack of observed thickness 

fluctuations below Tm is that if the decay times are slower (due 

for example to the higher bending rigidity) they will no longer be 

within our accessible time window. 

The amplitudes of the thickness fluctuations are related to 

the observed peak width, ξ-1, and can be estimated 

from dmξ-1/q [3]. As shown in Fig. 2c, this value is also 0

essentially independent of either tail length or temperature above 

Tm. The average thickness fluctuation amplitude was estimated 

to be (3.7 ± 0.7) Å, approximately 8 % of the membrane 

thickness, in remarkably good agreement with estimates based 

on both theory [4] and simulations [5,6], lending further 

support to our empirical model. Further, the amplitude is not 

significantly smaller than found that for surfactant membranes, 

suggesting the amplitude may be controlled more by the bilayer’s 

geometrical constraints such as volume conservation, rather than 

dynamical ones. If this holds below Tm then the lack of observed 

fluctuations would indeed be due to extremely slow relaxations. 

While these findings experimentally demonstrate the existence 

of thickness fluctuations in lipid membrane systems and provide 

some quantitative insights into them, there remains significant 

theoretical work on the physics of lipid bilayers in order to 

fully understand their dynamics. We hope that these findings 

will lead to other theoretical and experimental investigations of 

local intra-membrane dynamics to improve our understanding 

of these interesting systems. In particular exactly how these 

fluctuations might enable pore formation, membrane protein 

insertion, or other biological functions remain open questions. 

Fully understanding the dynamics in these systems will be key 

to, for example, designing therapies to control dysfunctions in 

membrane permeability and pore formation which can lead to 

cellular death. 

References 

[1] A.C. Woodka, P.D. Butler, L. Porcar, B. Farago, and M. 

Nagao, Phys. Rev. Lett. 109, 058102 (2012). 

[2] A.G. Zilman and R. Granek, Phys. Rev. Lett. 77, 4788 

(1996). 

[3] M. Nagao, S. Chawang, and T. Hawa, Soft Matter 7, 

6598 (2011). 

[4] H.W. Huang, Biophys. J. 50, 1061 (1986). 

[5] E. Lindahl and O. Edholm, Biophys. J. 79, 426 (2000). 

[6] B. West and F. Schmid, Soft Matter 6, 1275 (2010). 

Soft Matter
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 39 
Soft Matter
 

Electrochemical Small-Angle Neutron Scattering 

(eSANS) for studies of nanoparticle redox reactions 

V.M. Prabhu1 and V. Reipa2 

T

he redox properties of nanomaterials are crucial to 

applications such as in photocatalytic materials and 

in matching electronic band gaps for photovoltaic 

devices. Moreover, redox properties are also important 

to nanomaterial toxicology [1, 2]. With particle sizes of 

nanomaterials approaching the quantum confinement range and 

with conjugation to organic ligands (e.g., to stabilize dispersions for 

magnetic resonance imaging), their redox properties are governed 

by the position of their electronic band edges and may differ from 

the tabulated thermodynamic properties of bulk materials. 

Redox reactions can be controlled in electrochemical cells 

via changes in electrostatic potential. Optical spectroscopies 

(ultraviolet-visible, infrared, fluorescence, Raman) are the most 

common analytical techniques to follow species undergoing 

redox reactions in electrochemical cells. However, these 

methods do not provide the nanoscale structure (size and 

shape) or thermodynamic interactions (virial coefficients) under 

the reaction conditions, as can be obtained directly through 

scattering methods. Neutron scattering provides a unique 

capability to probe transformational kinetics for organic, 

inorganic, as well as composite particles with wide sensitivity 

at the nanoscale. Here we highlight our work demonstrating 

in situ electrochemical small-angle neutron scattering (eSANS) 

FIGURE 1: eSANS (electrochemical Small-Angle Neutron 

Scattering) cell . A highly porous, sponge-like carbon electrode 

maximizes surface area for electrochemical reactions while 

structural details like particle size and configuration are 

measured using neutron scattering (image at left) . 

measurements on ZnO nanoparticles undergoing reduction at 

potentiostatic conditions at an inert electrode [2]. 

The eSANS method was tested for feasibility with ZnO 

nanoparticles in a 50 mmol/L NaCl deuterium oxide solution 

undergoing bulk electrolysis at negative potentials. A 

potentiostat and eSANS cell with working porous carbon 

electrode in the beam and counter and reference electrode 

(Ag/AgCl) out of the beam was used on the NG-3 and NG-7 30 

m SANS instruments (Fig. 1). 

The macro to nanoporous vitreous carbon electrode with 

high surface area is highly conductive with negligible neutron 

absorbance and incoherent scattering. However, the nanoporous 

structure does give rise to small-angle scattering and Porod 

scattering arising from micropores. Contrast variation SANS 

with mixtures of D2O and H2O show an open-pore structure 

comprised of polydisperse nanopores of 6 Å radius and 0.05 % 

volume fraction. This choice of electrode material meets 

a critical criterion for electrochemical analysis in aqueous 

solutions, namely low probability for electrolysis of water (high 

overpotential). Unlike platinum working electrodes, carbon 

may be used at potentials to investigate the reduction of ZnO 

in aqueous solutions. The bulk Pourbaix phase diagram for zinc 

1 Polymers Division and 

2 Biochemical Sciences Division ; Material Measurement Laboratory ; National Institute of Standards and Technology; Gaithersburg, MD 20899 

40 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
shows where the stable oxidation states lie in the potential-pH 

plane. These diagrams, devised by corrosion science, also show 

that the reduction of zinc occurs at energetic potentials that are 

relevant to biochemical processes [1]. 

FIGURE 2: Selected eSANS data under forward and reverse potential 

scans . The inset shows current reading of the potentiostat vs 

controlled potential (vs Ag/AgCl) . 

A slow linear cathodic scan from –200 mV to –1200 mV (vs 

Ag/AgCl, 3 mol/L KCl electrode) at 6 mV/min was applied to 

a solution of ZnO in 50 mM NaCl in D2O. eSANS data were 

collected in 20 min intervals in average 120 mV increments for 

the forward and reverse scans. The D2O solvent-filled electrode 

was subtracted from the data to yield several eSANS curves at 

various potentials. A selection of eSANS data are shown in Fig. 

2 to illustrate the trends. The potential range covers an expected 

reduction of ZnO into Zn according to bulk Pourbaix diagrams. 

Figure 2 shows an increase in scattering intensity as the reductive 

current peak at ≈ –600 mV (shown in the inset) is approached 

in the forward scan, followed by a decrease in intensity across a 

broad Q-range and meeting towards high-Q beyond the peak. 

The scattering pattern remains unchanged with voltage during 

the reverse scan, indicative of an irreversible structural change. 

This irreversible signature is also observed in the current readout 

from the potentiostat, shown in the Fig. 2 inset, whereby a 

reductive peak appears in the forward scan, but no change upon 

reversal. 

The scattering was analyzed using Ornstein-Zernike plots to 

provide the correlation length, x, and scattered intensity at 

zero angle, I(0). The correlation length for fluctuations 

(Fig. 3) shows an irreversible structural change with a midpoint 

potential ≈ –650 mV. The correlation length is on the order of 

the nanoparticle radius of gyration without applied potential 

(open-circuit point) and increases near the current maximum 

during the forward potential scan, followed by a gradual drop 

consistent with an overall particle cluster-size decrease expected 

by partial ZnO to Zn transition. The complete reduction of 

Zn2+ to Zn0

 nanoparticles is unlikely, but the peak in x shows 

that clustering of multiple nanoparticles takes place, illustrating 

that the solution structure is dependent upon the redox potential. 

The reverse potential scan did not produce appreciable eSANS 

data variation, as shown in x plots vs E, implying an irreversible 

change in nanoparticle cluster size, but stable dispersion. 

The independent electrochemical readout and eSANS prove 

that the ZnO structure is coupled to the redox state changes 

quantitatively. 

FIGURE 3: Correlation length from an Ornstein-Zernike plot as a function 

of voltage during forward (closed symbols) and reverse (open symbols) 

scans, and open-circuit (black symbol) before the scans

Neutron scattering can follow these complex changes in situ 

under conditions that would be challenging for electron 

microscopy and optical spectroscopy. Combining SANS with 

electrochemical methods via porous vitreous carbon electrodes 

reduces observing an interfacial redox event into a bulk scattering 

method. It also allows monitoring redox structural changes in 

the dark, eliminating potential photochemical effects that are 

present when conducting optical spectroscopy of light sensitive 

nanoparticles, such as ZnO. The approach outlined here is 

extendable to contrast variation strategies. Importantly for 

eSANS, vitreous carbon has negligible neutron absorption and 

incoherent scattering contributions. Moreover, unlike platinum 

and gold working electrodes, carbon does not activate under 

direct beam exposure to high-flux neutrons, which makes it safer 

to use. This eSANS technique thus provides many opportunities 

to understand redox-related structural features of dispersed 

nanoparticle solutions. 

References 

[1] E. Burello and A.P. Worth, Nanotoxicology 5, 228 (2011). 

[2] V.M. Prabhu and V. Reipa, J. Phys. Chem. Lett. 3, 646 (2012). 

Soft Matter
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 41 
Soft Matter
 

Identifying the shape of copper-seamed 

nanocapsules in solution 

H. Kumari,1 S.R. Kline,2 N.J. Schuster,1 C.L. Barnes,1 and J.L. Atwood1 

Nanoscale materials based on the bowl-shaped members 

of the calixarene extended family continue to capture 

the imagination of the scientific community with 

potential applications in pharmaceuticals, catalysis, and 

as molecular magnets [1, 2]. One particularly robust, yet less 

investigated member of this family is the C-alkylpyrogallol[4] 

arene (PgCn). Recent studies have shown that PgC’s self-assemble 

into a wide range of supramolecular capsules based on both 

inter- and intra-molecular hydrogen bonding, as well as metal 

ion coordination. The guests in such capsules are generally small, 

polar molecules, but larger entities such as substituted pyrenes 

may also be housed in tubular structures and hexameric capsules. 

In the discussion of a complex supramolecular solid-state 

structure, a question always arises: what does the solid-state 

structure teach about the species present in solution? The answer 

to this question is typically based on nuclear magnetic resonance 

(NMR) evidence or sheer speculation. Small-angle neutron 

scattering (SANS), however, is capable of providing insight into 

the geometry of the species present in solution, regardless of the 

suitability of the sample for NMR or crystallographic analysis. 

Our interest in metal-seamed hexamers bearing long alkyl 

chains stems from the previously reported ellipsoidal assembly 

of C-undecylpyrogallol[4]arene hydrogen-bonded (PgC11) 

hexamers [3]. The solid-state structure of the PgC11 hexamer 

was obtained by a single crystal x-ray diffraction study in which 

it was found that the C11 alkyl chains were interdigitated in 

two-, not three-dimensions. This deviation from a 3-D spherical 

arrangement of the alkyl chains for carbon chains shorter than 

n =11 to a two-dimensional arrangement of the n > 11 alkyl 

chains led us to consider using longer alkyl chain hexamers 

as building blocks for even larger supramolecular assemblies. 

However, using single crystal x-ray diffraction for structure 

elucidation of nanocapsules with longer alkyl chains (n > 11) 

has proven difficult due to complexities in refining the long 

hydrocarbon chains. Thus, beyond the (PgC11) hydrogen-bonded 

hexamer, no long chain hexamer has been characterized in the 

solid state [3]. 

In the current study [4], copper-seamed nanocapsules of PgCs 

with long side chains were prepared (Fig. 1a and 1b). However, 

obtaining single crystals of the copper-seamed capsules suitable 

for diffraction has not been possible. In this case, SANS provides 

the only means to measure the structure. SANS from each 

of the nanocapsules was measured on the NG7 30 m SANS 

instrument by dissolving the previously isolated nanocapsules in 

an appropriate solvent. Crystals of PgC11Cu or PgC13Cu were 

dissolved in CDCl3 at a concentration of 3 % mass fraction, 

while PgC17Cu was dissolved in deuterated o-xylene at 1 % and 

5 % mass fractions. 

FIGURE 1: (a) Structure of pyrogallol[4]arene . Pendant alkyl chains are 

not drawn . (b) Hydrogen-bonded nanocapsule composed of a single 

C-heptadecylpyrogallol[4]arene (PgC17Cu) hexamer in the solid state . 

(c) A model of C-heptadecylpyrogallol[4]arene (PgC17Cu) hexameric 

nanocapsules assembled into an ellipsoid in solution, as measured 

using SANS (ellipse with axis ratio 4 .79 to guide the eye) . 

The scattering from PgC11Cu and PgC13Cu is shown in Fig. 2, 

and each curve was fitted very well with a monodisperse coreshell structure, with the core comprised of the pyrogallol[4] 

arene + Cu, and the shell of alkyl chains. Both capsules have an 

overall diameter of (44 ± 0.5) Å. It is not surprising for both 

nanocapsules to have similar dimensions since there is little 

difference in the alkyl chain length. 

The PgC17Cu capsules, however, show a very different structure 

in solution as seen in Fig. 3. For PgC17Cu in deuterated 

o-xylene, the SANS measurements are best fitted with a model 

of a prolate ellipsoid. The ellipsoids have a shorter axis of 

1 University of Missouri-Columbia; Columbia, MO 65211 

2 NIST Center for Neutron Research; National Institute of Standards and Technology; Gaithersburg, MD 20899-6102 

42 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
Soft Matter 

FIGURE 2: SANS data for copper-seamed hexamers of 

C-undecylpyrogallol[4]arene (PgC11Cu; blue circles) and 

C-tridecylpyrogallol[4]arene (PgC13Cu; red triangles) in CDCl3

 . The solid 

lines are resolution-smeared core-shell sphere model fits, and error 

bars on the data represent one standard deviation of the intensity . 

(48 ± 0.02) Å diameter and a major axis of (230 ± 0.2) Å. The

ellipsoid diameter is larger compared to the 44 Å diameter of 

the spherical PgC11Cu and PgC13Cu copper-seamed hexamers, 

as expected. The long axis dimension indicates the presence 

of one nanocapsule along the minor axis and approximately 

5 nanocapsules chained together along the long axis of the 

ellipsoid, held together through the interdigitation of the C17 

alkyl chains. Such a solution phase ellipsoidal nanocapsular 

assembly is drawn in Fig. 1c from the dimensions fitted to the 

data in Fig. 3. The ellipsoidal shape of PgC17Cu does not change 

with concentration (1 % or 5 %) mass fractions, indicating that 

the ellipsoidal assembly is an equilibrium structure rather than 

just aggregation or incomplete dissolution of the hexamers. 

These results reveal, to some extent, the limits to which selfassembled entities can stabilize in solution without aggregation, 

although it is reasonable to expect more complex assemblies to 

crystallize out. 

FIGURE 3: SANS data for PgC17Cu in deuterated o-xylene . The solid 

line is a global fit to both data sets using a resolution-smeared prolate 

ellipsoid model . 

In summary, the current study has revealed the stability of 

PgC11Cu and PgC13Cu hexamers in solution, which form coreshell spheres, and the formation of interdigitated ellipsoidal 

assemblies for PgC17Cu containing longer alkyl side chains. Such 

interlocking side chains facilitate the formation of larger multicapsule assemblies that mimic biological membranes connecting 

two adjacent cells or nanocapsules. SANS measurements 

have proven valuable in determining the solution structure 

of species that are difficult to crystallize, making solid-state 

structure determination impractical. This detailed structural 

characterization provided by SANS will help in understanding 

the limits of guest inclusion and the mechanisms of metalorganic nanocapsule formation, eventually allowing synthesis 

directed towards specific applications. 

References 

[1] J.W. Steed, J.L. Atwood, Supramolecular Chemistry, 2nd Ed., Wiley, 

Chicester, 2009. 

[2] J.L. Atwood, E.K. Brechin, S.J. Dalgarno, R. Inglis, L.F. Jones, A. 

Mossine, M.J. Paterson, N.P. Power, S.J. Teat, Chem. Commun. 

46, 3484 (2010). 

[3] G. W.V. Cave, S.J. Dalgarno, J. Antesberger, M.C. Ferrarelli, R.M. 

McKinlay, J.L. Atwood, Supramol. Chem. 20, 157 (2008). 

[4] H. Kumari, S.R. Kline, N.J. Schuster, C.L. Barnes, J.L. Atwood, J. 

Am. Chem. Soc. 133, 18102 (2011). 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 43 
 

 

Soft Matter
 

Characterizing dense polymer-nanoparticle 

mixtures by neutron scattering 

S.Y. Kim,1 K.S. Schweizer,1,2,3 and C.F. Zukoski1,2,3 

Achieving desirable properties in colloidal suspensions 

and polymer nanocomposites depends on 

controlling particle spatial organization and material 

microstructure. In concept, good dispersion of 

nanoparticles can be obtained by coating them with polymer 

layers in order to induce a repulsive inter-particle potential 

between them. Understanding the nature of, and what controls, 

the structure and properties of these bound layers remains a 

challenge. Obstacles limiting progress include (i) developing 

experimental tools for measuring the attraction strength of a 

polymer coated surface, (ii) differentiating polymer segments 

adsorbed on the nanoparticle surface from bulk polymer in the 

dense polymer solutions or melts, and (iii) measuring the packing 

structure of both segments and particles over a wide range of 

length scales and volume fractions. In this highlight we present 

experimental results addressing the above issues using contrast 

matching small angle neutron scattering (SANS) techniques in a 

thermodynamically stable system that is a mixture of short chain 

polymers, nanoparticles and solvent. By measuring the intensity 

of scattered neutrons while varying the scattering contrast 

between components using D2O/H2O mixtures, all three 

partial coherent structure factors arising from polymer-polymer, 

particle-particle, and interfacial concentration fluctuations can be 

determined. 

Silica nanoparticles of diameter D = 40 nm are synthesized 

via the standard Stöber process and suspended in dense 

polymer solutions composed of poly(ethylene glycol) (PEG) of 

molecular weight 400 Da and D2O and H2O solvents. Polymer 

concentration, defined as the ratio of PEG to (PEG-plus-solvent) 

volumes (RPEG), is fixed at a high value of 0.45. This ensures 

physical behavior representative of melts since the monomer 

collective density fluctuation correlation length is of order of the 

nanometer segment size. Silica volume fraction (φc) is varied 

from 0.05 to 0.30. All experiments are performed at room 

temperature, and we find no evidence of aggregation or phase 

separation. Intensities of scattered neutrons were measured in 

the range of 0.004 Å-1 < q < 0.04 Å-1, which corresponds to a 

reduced wave vector range of 1.6 < qD < 13. 

The intensity of scattered neutrons at wave vector q, I(q), has 

three contributions: 

I(q)=ncΔrc 

2

Pc(q)Scc(q,φc)+2ΔrcΔr √ncnpPc(q)Spc (q)+npΔrp 

2 Spp(q), (1) 

where nj = βjVj

2

, and βj and Vj are the number density and unit 

volume of the jth component, respectively. Δrj is the difference 

in scattering length density (SLD) between component j and the 

medium, Pc (q) is the silica particle form factor, and Sij(q) is the 

partial structure factor associated with different components and 

their cross correlation terms (pp, pc, cc) where the subscript p 

stands for polymer and c for silica particles [1]. 

In order to extract all three partial structure factors Sij(q) at a 

fixed silica particle volume fraction φc, the D2O/H2O ratio 

of the solvent is varied so that the SLD contrast of different 

components is changed accordingly. For example, when the 

D2O/H2O ratio is chosen to match the SLD of polymer (Δrp = 

0) the measured scattering intensity is caused only by the silica 

particles, so that Eq. (1) reduces to I(q) =ncΔrc 

2

Pc(q)Scc(q,φc ). 

The form factor Pc (q) of the silica particles is determined at a 

low particle volume fraction. Then Scc(q) at large concentrations 

is obtained by dividing the scattering intensity by ncΔr 2

Pc(q) c 

[1]. Using the results from three D2O/H2O ratios, we solve 

the multiple linear equations simultaneously by multiple linear 

regression fitting methods to obtain the polymer-polymer 

Spp(q) and polymer-particle Spc(q) partial structure factors. The 

technical details are given in [1]. 

Measured scattering patterns are compared with the standard 

polymer nanocomposite version of the PRISM integral equation 

theory where the solvent enters implicitly, details of which 

are thoroughly documented in the literature [1-3]. All species 

interact via pair decomposable site-site hard core repulsions. 

The chemical nature of the mixture enters via an exponential 

monomer-particle interfacial attraction, Upc(r)= –εpcexp{­

[r–(D+d)/2]/αd}, where εpc is the net energy released when 

transferring a polymer segment (diameter, d) of the freely jointed 

chain from a concentrated polymer solution environment to the 

nanoparticle surface (diameter, D), and a = 0.5 is a spatial range 

parameter. A chain length N = 100 is used as representative of the 

equilibrium behavior of polymers [2]. With all the information, 

the partial structure factors (Sij(q) ) can be calculated using 

PRISM theory [2]. 

Experimental partial structure factors at various φc are shown in 

Fig. 1. The partial structure factor of silica particles Scc(q) has a 

form characteristic of a correlated fluid. Both Scc(q) and Spp(q) 

display peaks near qD ≈ 4 to 6. The peak in Scc(q) is associated 

with a liquid-like nanoparticle packing, while the intense 

“microphase-like” peak in Spp(q) occurs at a length scale which 

greatly exceeds that of the PEG radius-of-gyration. Its physical 

origin is spatial correlations between adsorbed polymers with 

non-bulk-like properties mediated by nanoparticles [1]. 

1 Department of Chemical & Biomolecular Engineering; University of Illinois; Urbana, Illinois 6180 

2 Department of Materials Science; University of Illinois; Urbana, Illinois 61801 

3 Frederick Seitz Materials Research Laboratory; University of Illinois; Urbana, Illinois 61801, USA 

44 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
Experimental Scc(q) and Spp(q) were compared with theoretical 

calculations for interfacial attraction strengths: 0.25 kBT < εpc

< 1.05 kBT (not shown, see [1]). Good agreement between 

theory and experiment is found for both Scc(q) and Spp(q) with a 

common value of εpc = 0.45 kBT for all particle volume fractions. 

In Fig. 1, increasing φc suppresses long wavelength (qD < 4) 

nanoparticle concentration fluctuations Scc(q), but enhances 

polymer fluctuations Spp(q) in the same range. At larger qD the 

increased height and shift of the first peak in Scc(q) indicates a 

more ordered first neighbor shell, while increased coherency of 

polymer segment density fluctuations on the nanoparticle length 

scale is deduced from the form of Spp(q). The right inset shows 

that the cross partial structure factors Spc(q) are negative, and 

with increasing wave vector they decrease and goes through a 

minimum at qD ≈ 4 to 6. These features indicate anti-correlation 

of particle and polymer segment concentration fluctuations over 

a wide range of length scales. As φc increases, the minimum in 

Spc(q) grows in magnitude and occurs at larger qD, tracking the 

increased local interparticle correlation and also the growth of 

the Spp(q) peak. Taken together, there is remarkable agreement 

between all three experimental structure factors and PRISM 

theory over a wide range of wave vectors and all volume fractions 

based on a volume fraction independent value of εpc. This provides 

significant support for the intrinsic material origin of εpc, the 

dominance of the interfacial attraction strength in determining 

both polymer and particle microstructures. 

To characterize adsorbed polymer layers on the nanoparticles 

in situ, a system is investigated when the SLD of silica particles is 

matched by the solvent (ΔҐc = 0). Hence, the scattering intensity 

is due to non-bulk-like polymer concentration fluctuations from 

shells of adsorbed polymer (cartoon in Fig. 2). The polymer 

partial structure factor in Eq. (1) can then be approximated 

as Spp(q) ≈ S*pp(q) Ps(q), where Ps(q) is the form factor of the 

polymers adsorbed on a silica particle surface. The adsorbed 

polymer forms a shell around a silica particle. Spp*(q) is the 

structure factor associated with correlations between the centersof-mass (CM) of these polymer shells. We argue that the CMs 

of the adsorbed polymer shells to a good approximation have 

the same correlations as that among the silica particles (Spp*(q) 

≈ Scc(q)). Under this assumption, an experimental form factor of 

the polymer shell Ps*(q) can be defined and obtained. 

Figure 2 presents the experimental Ps*(q), and the PRISM theory 

analog determined in the same manner. We note that Ps*(q) 

results from well-defined adsorbed polymer layers (cartoon) 

that are structurally distinct from bulk polymers. Varying φc,

the resulting Ps*(q) values overlap well. Using scattering length 

density parameters at a match condition and a core-shell model 

form factor [4], the adsorbed shell thickness is determined [1] 

to be ≈ 0.7 nm to 1 nm, which is modestly larger than the PEG 

segment length. Spp(q) and Spc(q) contain critical information 

that allows the determination of the thickness of the polymer 

layer adsorbed on the silica nanoparticles under dense conditions. 

In summary, using contrast matching neutron scattering we 

have measured and compared to the theory, for the first time, 

all collective partial structure factors in concentrated polymernanoparticle mixtures. We established the existence and size 

of adsorbed polymer layers and their consequences on dense 

solution microstructures. 

FIGURE 1: Polymer collective structure factor Spp at different 

nanoparticle volume fractions, øc . Corresponding curves are the PRISM 

theory results for εpc = 0 .45kBT . Left and right insets: Scc and Spc under 

the same conditions . 

FIGURE 2: Adsorbed polymer shell form factor (Ps *(q)) from PRISM 

theory (solid curve) and experiment (dots) . The dash-dot line is a fit 

to the form factor of a core-shell model . The bare spherical-particle 

form factor, Pc(q), is shown as the short dashed curve for comparison 

to Ps *(q) . 

References 

[1] S.Y. Kim, K.S. Schweizer, C.F. Zukoski, Phys. Rev. Lett. 107, 

225504 (2011). 

[2] L.M. Hall, B.J. Anderson, C.F. Zukoski, K.S. Shweizer, 

Macromolecules 42, 8435 (2009) . 

[3] S.Y. Kim, L.M. Hall, K.S. Schweizer, C.F. Zukoski, 

Macromolecules 43, 10123 (2010) . 

[4] S.R. Kline, J. Appl. Cryst. 39, 895 (2006). 

Soft Matter
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 45 
 

A Liquid Deuterium Cold Neutron Source for the NBSR
 

R. E. Williams, P. Kopetka, J. M. Rowe and M. Middleton 

Advances in Measurement
 

Aliquid deuterium cold neutron source is being designed 

and built to replace the existing liquid hydrogen 

source installed in 2002. The LD2 source will shift the 

neutron spectrum to lower energies, with gains of 1.4 

to 1.8 for neutrons with wavelengths between 4 Å and 9 Å. This 

project has received funding from the National Nuclear Security 

Administration Global Threat Reduction Initiative (DOE) as 

a mitigation strategy to offset the expected 10 % flux decrease 

in NBSR beams when the reactor is converted to low-enriched 

uranium (LEU) fuel. 

Work on the deuterium source actually began a few years ago but 

was suspended for lack of sufficient funding for a new helium 

refrigerator. Monte Carlo simulations using MCNP indicated 

that a very large volume source was needed to realize the above 

mentioned gains, and the anticipated nuclear heat load would 

exceed the capacity of the existing refrigerator. The earlier work 

showed that the bigger the LD2 volume the greater the gain, 

but the gains increase more slowly than the heat load. As a 

result, it was decided a 40 cm long by 40 cm ID vessel would 

provide excellent gains with a modest heat load of about 3500 

W. At this power, it is expected that the void fraction in the 

boiling liquid deuterium will be 13 % ± 5 %. The gain as a 

function of wavelength is shown in Fig. 1 for the 40 x 40 source. 

“Fine-tuning” of the gains can be accomplished by varying 

the re-entrant hole depth, with a deeper hole favoring short 

wavelengths, and vice versa; a 18 cm depth maximizes the gain 

between 4 Å and 8 Å. The hole diameter, 22 cm ID, assures full 

illumination of all of the neutron guides to at least 10 Å. 

FIGURE 1: Expected gains of the LD2 cold source with respect to the 

existing LH2 source

Figure 2 is an MCNP geometry plot of the source (plan view) 

in the cryogenic thimble of the NBSR. The source will be 

surrounded by insulating vacuum and a helium containment 

FIGURE 2: A plot of the MCNP geometry used for cold neutron 

optimization and nuclear heat load calculations showing the major 

features of the 40 x 40 cm LD2 source . 

jacket strong enough to withstand the pressure of the maximum 

hypothetical accident (these jackets are combined in the model). 

The cryostat assembly must also be cooled with D2O. This water 

jacket serves as part of the core reflector, so it will surround the 

source to the greatest extent possible without cutting into the 

cold neutron beams. The assembly will be installed horizontally 

in the CT cavity and a deuterium condenser will replace the 

existing LH2 condenser on the north face of the biological shield. 

The thermal-hydraulic design of the LD2 source is based on 

the very successful horizontal source at ILL in Grenoble. Its 

designers published the results of their pressure and temperature 

measurements on a full-scale LD2 mockup of that source, which 

has a slightly lower heat load, 3000 W, but a much smaller 

volume. By scaling up the inside diameters of the liquid supply 

line to 22 mm and the two-phase return line to 31 mm, the 

NBSR source can easily operate as a thermosiphon with the 

available driving head of about 2 m between the condenser and 

the source. A perforated section of the return line at the top 

of the vessel allows a two-phase mixture of LD2 and the vapor 

generated in the source to flow back to the condenser, ensuring 

that the vessel remains full of liquid. The source will operate at 

23 K, the boiling point of deuterium at 1.0 bar. 

The conceptual design of the LD2 source is nearly complete. A 

contract for a 7 kW refrigerator was awarded in April; its delivery

is scheduled for early 2014. Specifications for a 6 kW deuterium 

condenser and a 16 m3

 ballast tank have been sent to procurement. 

The mechanical design of the moderator vessel is complete so it 

will soon be possible to build and pressure-test a prototype. The 

goal is to build or procure all the major components in the next

3 years and install the source shortly thereafter. 

NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899 

46 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
Expansion Activities During the Planned Outage
 

I

n April 2011, the reactor shut down for an extended outage 

in order to accomplish the many tasks associated with the 

multi-year NCNR Expansion Project and infrastructure 

enhancements. Planning for all of the activities in this major 

outage began well over a year prior to the shutdown and involved 

organization and planning across Reactor Operations and 

Engineering (ROE) and the Research Facility Operations (RFO) 

Groups. Major construction work in building 235 (supported 

through the American Recovery and Reinvestment Act) included 

a number of reliability enhancements to the facility. This work 

was carried out by independent contractors and it imposed 

specific scheduling constraints requiring detailed coordination 

with the work carried out by the NCNR staff. This period 

included the most complex set of activities undertaken by the 

NCNR in any single reactor shutdown period. The results of the 

detailed planning and coordination were that all planned projects 

were completed successfully and the facility was able to restart 

for user operations in April 2012. This section describes some 

of the major activities carried out by ROE and RFO during the 

extended outage. 

Reactor Operations and 


Engineering Activities
 

Reactor Spent Fuel Storage Pool Refurbishment 

The spent fuel storage pool contains 125 m3 (33 000 gallons) 

of water with trace levels of radioactivity requiring disposal as 

hazardous waste or temporary storage in tank trucks for any work 

requiring the pool to be emptied.   Hence, the NCNR evaluated 

several contractors and chose to use a commercial diver company 

that could perform all the activities, including recoating the 

pool, without draining the original pool water.   The selected 

dive company had extensive experience doing similar projects at 

nuclear power plants.  Performance of the refurbishment with 

divers added a degree of complexity but this was outweighed by 

the benefits of significantly reduced personnel radiation doses 

and lowered safety risk (working around the empty pool). One 

of the functions of the water in the pool is to provide radiation 

shielding from the radioactive materials stored within the pool.  

Removal of the water prior to commencing the refurbishment 

work would likely have increased the radiation exposure to the 

individuals working within the drained pool until the stored 

equipment and loose radioactive materials were removed. 

Initial work required plasma cutting of several large storage 

racks so they could be removed and placed into waste disposal 

FIGURE 1: Diver (right) exiting the spent fuel storage pool

containers.  When the divers began to remove the original 

coating on the concrete walls of the pool, they found that 

removal was unexpectedly difficult due to the concrete 

surface not being trowel finished as per the original building 

specification. Because of the rough finish, the divers had to hand 

scrape the material off the concrete instead of using a power 

washer to do so.  Application of the new coating also was more 

difficult than expected due to the rough texture of the pool 

walls. Nonetheless, the dive team completed the recoating of the 

pool and the installation of new fuel storage containers without 

impacting the overall restart schedule.  

Replacement Secondary Cooling System 

It was noted while planning the expansion project that the new 

neutron guides would pass over the existing secondary cooling 

pump rooms and block an access hatch used to remove pumps 

and motors for maintenance or replacement. Due to the age of 

the secondary cooling system and the expected access problems, 

the decision was made to replace the system, installing it in a 

new building. The original secondary cooling system used six, 

constant speed pumps but the new system has four variable 

frequency drive pumps with only three needed to cool the 

reactor and auxiliary systems. The additional cooling provided 

by a new 7 MW cooling tower beside the original 20 MW 

tower supported the future installation of a liquid deuterium 

cold neutron source and added supplemental heat removal for 

the hot and humid Maryland summers. The power for these 

new systems came from a new electrical substation also installed 

behind the NCNR. The substation reduced the load on the 

NCNR electrical system which would then support the increased 

electrical demand from the neutron instrumentation growth in 

the expanded guide hall. 

Expansion Activities During the Planned Outage
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 47 
 

Expansion Activities During the Planned Outage
 

Commissioning and Operational Phase of the 

Thermal Shield System 

The reactor is equipped with a radiation shield (the “thermal 

shield”) to absorb radiation, allowing closer access around the 

reactor vessel for experimental equipment and less concrete 

biological shielding protecting personnel. It is located 

immediately around the vessel and consists of a 15 cm (6 inch) 

thick steel tube clad on the inside with a 5 cm (2 inch) thick 

lead layer. Soldered onto the inside diameter of the steel tube 

(thus surrounded by the lead) are 188 copper cooling lines which 

circulate water to allow the removal of heat that is deposited 

into the thermal shield by intense gamma radiation generated 

in the reactor core, in order to keep the shield at a temperature 

where it does not change shape under its own weight. Over the 

many years of pumping water under pressure, the thermal shield 

plumbing has developed tiny leaks which are impossible to repair. 

The upgrade converted the previously pressurized coolant-flow 

system into a vacuum operated system that “pulls” the coolant 

through the copper lines. The operating vacuum is created by an 

aspirator which maintains the entire cooling system at a pressure 

lower than atmospheric and prevents liquid from leaking from 

the small holes in the copper lines. The upgraded system was 

prototyped at the NCNR by Paul Brand and Tony Norbedo over 

several years to evaluate the flow method and develop chemistry 

controls. 

FIGURE 2: Tony Norbedo and Paul Brand inspecting headers of the 

thermal shield cooling system

The complete upgrade design was fully mocked-up at the factory 

and tested prior to any demolition of the original NCNR system 

to minimize the risk to the NCNR and the Outage schedule. 

Some cooling lines had been isolated because the leaks were 

found to be too large and temporary repairs were not successful. 

The upgrade to the thermal shield system has allowed some of 

these lines to be returned to service and increase the cooling to 

these locations in the thermal shield. The upgrade for the thermal 

shield cooling system included a full digital monitoring and 

control system. This system acquires flow rate data from all 188 

cooling lines and many other process parameters, permitting 

detailed system performance analysis and automatic protection 

action when certain parameters are out of specification. The 

data acquired helped identify flow oscillations on some lines 

early during the testing phase which were eliminated by the 

installation of a bypass line to reduce local flow starvation. The 

trending of process data to identify system design problems or 

potential equipment failures is a powerful diagnostic tool that has 

not been previously available for many of the NBSR systems but 

will eventually be available for nearly all NBSR parameters as the 

reactor control console is upgraded to a full digital monitoring 

system. 

Reactor Control Room Upgrade 

The NBSR reactor control console is in a continuous state of 

evaluation and upgrade to assure the equipment is maintained 

at a high level of reliability. Systems are upgraded if repairs 

are not successful or parts are no longer available. A complete 

replacement of the reactor control console was planned prior to 

the Outage but resource limitations and unacceptable scheduling 

risk convinced NCNR management that a longer term console 

replacement project schedule was preferred. During the Outage, 

a majority of the indications, alarms and process (non-reactor) 

controls were replaced with systems that could communicate via 

the dedicated, isolated control room network. These systems 

could now provide data to an acquisition system where it would 

be stored for analysis or be used for real-time reactor plant 

monitoring. A new facility was constructed near the NBSR 

Control Room to house the data acquisition system servers and 

allow prototyping of upgraded control systems and the HMI 

(Human-Machine Interface) screens. 

Installation of Second Hydrogen Cold Source in BT-9 

The addition of new neutron guides during the Expansion 

required moving the MACS (Multi-Angle Crystal Spectrometer) 

instrument. MACS uses cold neutrons so the instrument 

movement project included the installation of a second, smaller 

liquid hydrogen cold source. Unexpected conditions and 

material degradation within the beam tube required machining 

of the inner beam tube walls to permit the installation of the cold 

source unit. Cooldown and liquefaction of hydrogen in both 

cold sources finally occurred in mid-March because the testing 

of both cold sources and operating the reactor above 1 MW 

required the new secondary cooling system to be functional. 

Initial testing of the cold sources at full power (20 MW) occurred 

on April 12 with the new systems accepted for normal operation 

on April 24. Neutron spectrum measurements from the BT-9 

cold source will be performed when MACS is fully installed and 

operating sometime in early 2013. 

48 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
FIGURE 3: Robert Williams monitoring the first cool down of the two cold 

sources that use the same refrigerating system

Research Facility Operations Activities 

Installation of the new guide network 

A central feature of the Expansion Initiative is the addition of 

a new guide network to accommodate instruments in the new 

guide hall. Installation of these five new guides presented a 

series of engineering, technical, and logistical challenges that are 

described here. 

Precise alignment of individual guide elements is critical to the 

transmission efficiency and ultimate performance of any neutron 

optics system and installation of the Expansion guide network 

posed specific new challenges. Whereas the existing guides at 

NCNR (NG-1 through 7) have straight flightpaths and are of 

rectangular cross-section, the new NG-A through D guides are 

designed to capitalize on major developments and improvements 

in neutron guide optics and design technology over the past 20 

years. They are curved to help reduce spectrometer background 

arising from gamma rays and fast neutrons by siting instruments 

beyond the line-of-sight of the source and, in the case of NG-A 

and NG-D, have quasi-elliptical cross-sections when viewed from 

the side to improve transmission efficiency and beam reshaping. 

Moreover, installation of the new guides had to be achieved 

within the tight constraints imposed by existing Facility 

installations. The guides traverse a path from the cold neutron 

source situated in the confinement building, through the D-wing 

- a former utility area - and then, finally, into the G-100 guide 

hall. These factors were compelling in the decision by the inhouse engineering and technical installation staff to switch from 

conventional analogue alignment methods, which typically use 

theodolites, and adopt new techniques that use laser-tracker 

and digital level technology coupled with a portable co-ordinate 

measuring machine to characterize each guide section. 

Prior to installation, each of over 360 individual sections 

comprising the 260 m long guide network was first characterized 

(fiducialized) using the measuring arm (see Fig. 4). At key stages 

of the installation, local control networks were set up using the 

laser tracker to define co-ordinate measurement systems in the 

confinement building, the D-wing, and the guide hall. These 

three discrete areas were then linked-or ”tied in”-to form a 

Facility-wide coordinate system by employing optimized lineof-sight penetrations that were bored between each area as part 

of the outage construction activities. Local area coordinate 

networks were also set up in a high bay assembly area and 

a portion of the new guide hall to enable pre-assembly and 

alignment of a large percentage of the guide network prior to 

final installation. These pre-assembly and alignment activities 

enabled the final installation to proceed smoothly and with 

minimal delay. This efficiency during installation ultimately 

proved critical in maintaining the outage schedule. 

FIGURE 4: Doug Ogg (left) and Mike Rinehart use a measuring arm to 

characterize an element of guide NG-C

At the start of the outage, technical staff removed hundreds 

of tonnes of steel and wax shielding from the confinement 

building to expose the Cold Tube West (CT-W) viewport to the 

hydrogen cold source required by the new guides. This location 

was formerly occupied by the multi-angle crystal spectrometer 

(MACS) and so the spectrometer also required dismantling. 

A full three months of preparatory work was required before 

installation of the new guides could begin in the confinement 

building. 

The origin of the guides is the “in-pile” plug (Fig. 5). This 

element required alignment inside the biological shield of the 

source to within a fraction of a degree in order to ensure that the 

resulting guide flight paths were correctly aligned and conformed 

to tight constraints imposed by existing Facility building 

infrastructure. 

The in-pile guide monolith is constructed using highly-polished 

aluminum rather than a conventional glass substrate material. 

Recent advances in supermirror technology have enabled this use 

of metal substrates which offer considerable advantages 

Expansion Activities During the Planned Outage
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 49 
Expansion Activities During the Planned Outage
 

FIGURE 5: The in-pile plug containing the metal-substrate supermirror 

guides comprising the first section of the new guide network . 

given their ability to withstand the high levels of neutron 

bombardment received close to the source. The shutdown also 

provided an ideal opportunity to replace the CT-E plug, serving 

the existing NG-5 through 7 guides, with metal in-pile guides so 

as to promote reliable operations for those guides in the future. 

Once the in-pile plug had been set, a series of steel vacuum 

vessels containing sections of glass guide were then installed. All 

the new guides have curved flightpaths and so, as the beamlines 

diverge, the guides transition from a monolithic housing to 

discrete vacuum jackets and dedicated shutter mechanisms before 

leaving the confinement building. Although the confinement 

building houses only some 25 % of the total guide network, 

it was arguably the most challenging phase of the installation 

with the addition of the in-pile plug, shutter, vacuum and other 

ancillary systems in this area. Today, the unremarkable shielding 

that can be seen covering this area belies the true complexity of 

the guide system housed inside. 

Construction activities played a major role in the guide 

installation project, not least in the conversion of the D-wing 

utility area into a structurally reinforced chamber capable of 

supporting the new guide and shielding infrastructure and with 

the necessary wall penetrations through which the steel vacuumjacketed guides pass from the confinement building and into 

the guide hall. Physical access into the D-wing was extremely 

limited. During construction and installation, all building 

materials and components of the guide network had to pass 

either through the wall penetrations (see Fig. 7 below) or enter 

via a personnel door of standard dimensions. These restrictions 

were skillfully overcome by first constructing sidewall shields 

with poured-in-place concrete before individual approximately 

7.6 m (25 ft) long steel vacuum-jacketed guide sections for 

each guide were rolled into place from the guide hall side. The 

guide sections were all pre-aligned and, by virtue of the smooth 

transport mechanism designed, needed only minimal adjustment 

once installed within the confines of the D-wing. The D-wing 

was completed by installation of a 61 cm (2 ft) thick roof shield. 

In this case the execution owed less to ingenious design and more 

to brute force with the 25.4 t (65 000 lb) shield constructed 

using over 2700 pavers — all stacked by hand! 

FIGURE 7: Danny Ogg and Mike Rinehart work with Dan Adler (center) in 

aligning the vacuum-jacketed NG-D guide inside the D-wing . 

FIGURE 6: A view of the new guides and shields in the latter stages of installation in the confinement building, coming from the reactor on the right and 

entering D-wing on the left ( The apparent curvature is an artifact arising from the fisheye-lens camera ) 

50 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
FIGURE 8: Guide installation in G-100 . Viewing left to right, the completed NG-D and NG-C guides are seen emerging from end windows of the blue 

shielding while installation of the as-yet unshielded NG-B guides continues behind

The final installation phase in the guide hall brought the relief 

of an essentially open and vacant site in the new (East) guide 

hall. Design and installation challenges remained however, not 

least along the boundary region between old and new guide 

halls where guide and shield components are located outside the 

reach of the overhead cranes of both halls. This required using a 

forklift truck to carefully maneuver massive shielding blocks to 

within inches of the now exposed glass — in G-100 the guide 

sections are no longer housed in steel vacuum jackets. It is 

testimony to the skill of the installation team that throughout the 

project, despite multiple handling activities, not a single segment 

of guide glass was damaged. 

TABLE 1: Guide installation facts and figures 

The final sections of the NG-D through B guides were installed 

rapidly once the network entered within the reach of the crane 

in the new guide hall. On NG-D, local instrument shutters and 

monochromater tables were installed in sequence with the guides. 

Since the fit-up of electrical and instrument controls proceeded 

in parallel with the guide installation, the Polarized Beam and 

MAGIk reflectometers were already being installed on NG-D 

while the NG-B guides were being completed. With the 10 m 

SANS instrument already pre-staged for installation on the lower 

NG-B guide, the first three instruments on the new guides are 

poised for the start of commissioning activities. 

Expansion Activities During the Planned Outage
 

Total Guides installed length (m) 261 

Total Guide elements aligned 361 

C-100 Shielding installed (t/lbs) 136/300 000 

D-100 Shielding hand-stacked (t/lbs) 29.5/65 000 

G-100 Shielding installed (t/lbs) 453.6/1 000 000 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 51 
Neutron Source Operations
 

Neutron Source Operations


T

he first startup to100 kW of the neutron source from 

the extended shutdown occurred on February 8, 2012 

for low power testing. Higher power testing required 

the new secondary cooling system to be functional 

and 1 MW operation for radiation surveys occurred on March 

15. The following month was required to bring systems back 

into service and to commission new equipment such as the 

secondary system, thermal shield cooling system, and the BT-9 

cold source. The NBSR officially started normal user operations 

on April 26 and the Outage was declared over after 389 

days. Although Users were now able to perform experiments, 

the NCNR staff continued working hard behind the scenes 

to complete the installation and continue testing of some 

equipment not considered essential for initial User operations 

but necessary for long-term, reliable operation. Essentially, 

the first few cycles after the Outage were used to evaluate and 

operate new systems or those that had not been used for over a 

year while providing neutrons to the User program. Relatively 

few unplanned shutdowns of the neutron source occurred from 

equipment problems after the restart of user operations. The 

NCNR neutron source achieved a remarkable 92 % reliability in 

2012 owing to the high quality of the maintenance and upgrades 

performed by the Reactor Operations and Engineering group 

(ROE) and their ability to safely make modifications to systems 

without requiring the reactor to be shutdown. 

A system that had not been installed on April 26 was the fuel 

transfer system (FTS). The system is used to move spent fuel 

from the reactor into the storage pool and, occasionally, back to 

the reactor. The FTS had been partially refurbished during the 

Outage but could not be tested until it was returned to the pool 

area in late March. The FTS did not operate correctly during 

testing and it was found that the hydraulic seals that actuated 

the mechanism leaked excessively. Waiting for the new seals to 

arrive would have delayed the return to normal User operations 

by several weeks. NCNR management chose to startup the 

facility and return to 20 MW operations as scheduled and 

install the FTS in the spent fuel pool during the next shutdown. 

Additional problems with the FTS were discovered over the next 

month and the system was not ready for installation as expected. 

The neutron source was started up without refueling to support 

the annual neutron scattering school and then shutdown again 

after one week of operation. The FTS was finally tested and 

reinstalled on July 2. 

The upgraded thermal shield system performed remarkably 

well but some problems were noted during testing in the first 

two cycles after the Outage. Cooling water flow rate to each of 

the 188 lines is an important parameter to assure protection 

of the thermal shield. If lines in a particular area have no flow 

or significantly reduced flow it could damage the lead of the 

thermal shield. The thermal shield instrumentation system 

prevents damage to the lead if cooling flow is lost by causing an 

automatic reactor power reduction (reactor rundown). Using 

the new trending function of the digital control system it was 

noted that flow in some lines dropped after the reactor reached 

full power and this sometimes 

caused a reactor rundown. The 

ROE engineers and operators 

developed several mitigation 

methods including scouring 

out the tubing with a mild, 

non-reactive abrasive to remove 

loose debris clogging the lines 

and this improved flow rates on 

some lines. There have been 

no low-flow rundowns since 

the implementation of these 

improvements on the system 

but the ROE continues to 

monitor the performance. 

Senior Reactor Operator 


Jeff Burmeister starts up the 


NCNR reactor

52 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
Facility Development 

F

acility support staff met the end of the long outage 

by successfully bringing the existing complement of 

instruments back into operation after nearly a year 

shutdown. In addition to activities directly associated 

with the Expansion Initiative described earlier (p. 47) progress 


was also made in many other areas. 


Instrument Development 

NCNR has two major new instrument projects running: 

CANDoR, a white beam reflectometer, and the Very Small 

Angle Neutron Scattering spectrometer (vSANS). Detector 

procurement and development for these instruments has been a 

major component in their programs this year. 

NCNR has initiated a development program for solid state 

scintillation detectors that are needed to replace conventional 

3

He gas tubes due to the projected shortage of 3He. Scintillator 

technology is also advantageous for instrumental applications 

where more compact devices are required as is the case with 

the energy sensitive neutron detector in design for first use 

on CANDoR. The Facility was awarded NIST intramural 

funding to support staff for the development of the CANDoR 

detector which utilizes a sliver of 6

Li/ZnS(Ag) scintillator as 

the neutron-sensitive element and wavelength shifting fibers to 

conduct the scintillator light to silicon photomultiplier devices 

(SiPMs). This construction allows detectors to be very thin 

(≈ 1mm), permitting many more channels of crystal-analyzed 

neutron detection than a similar arrangement using gas-filled 

pencil detectors. This year, as part of this development program, 

a detector development station has been commissioned on 

the NG-1 beamline (Fig. 1) providing a monochromatic 

neutron beam (4.75 Å wavelength, with a fractional wavelength 

resolution of approximately 1 %) to establish the performance 

properties of the scintillator and optimize the configuration and 

type of fiber optics and electronics used. 

The design of the vSANS spectrometer calls for two types 

of detectors: a high resolution area detector typical of most 

instruments of this type and arrays of linear position sensitive 

tubes. While no candidate has been positively identified for the 

high resolution detector, NCNR took delivery of eight panels 

of “8-pack” linear position sensitive 3

He proportional counters 

for incorporation into the spectrometer (Fig. 2). Since delivery, 

facility staff members have been working to characterize the 

readout electronics based on the Spallation Neutron Source data 

acquisition standard. 

FIGURE 1: Nick Maliszewskyj, Chuck Majkrzak (mostly hidden), 

Brian Maranville, and Jeff Ziegler assess data from the new detector 

development station at NG-1 . 

Neutron Spin Filters 

The NCNR’s program to provide and develop 3He neutron 

spin filters (NSFs) is operated in collaboration with the Physical 

Measurement Laboratory at NIST. In the current reporting 

period, which includes the outage period, user experiments 

were only performed during two reactor cycles prior to the 

long shutdown. Nevertheless, the spin filter program serviced 

14 user experiments, for a total of 43 beam days requiring 

about 76 bar-liters of polarized 3

He gas. Polarized beam 

experiments are routinely carried out on the thermal neutron 

triple-axis spectrometer BT-7, on small-angle neutron scattering 

instruments, on the Multi-Axis Crystal Spectrometer (MACS), 

and on the reflectometers. Results from the first user experiment 

to employ wide-angle polarization analysis on MACS have now 

been published [1]. 

FIGURE 2: Assembled “8-pack” 3He proportional counter arrays for vSANS

Facility Development
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 53 
Facility Development
 

3

He gas is polarized by spin-exchange optical pumping (SEOP), 

in which alkali-metal atoms are polarized by optical pumping 

and the resulting electronic polarization is transferred to 3

He 

nuclei in spin-exchange collisions. The performance of the 

SEOP systems, 3

He cells, and 3He polarization continues to 

improve and, to address increasing user demand, a third SEOP 

system will be implemented shortly. A major technical barrier 

in fabricating large (over 1 L), high-pressure 3

He cells has been 

successfully overcome and three such cells have been produced 

to enable efficient polarization of 50 meV neutrons on BT-7. 

Characterization of the polarized neutronic performance for 

these cells is underway. In addition, two new SANS cells are now 

available for user experiments. 

Standard protocols have been developed and are now available 

for routine use in polarized neutron scattering measurements at 

the NCNR. A standardized measurement sequence is necessary 

for measurement of 3

He polarization and flipping ratio versus 

time, polarization efficiency calibration, and spin-transport 

configurations for user experiments. The goal is to provide an 

integrated, user-friendly 3

He NSF package and hence to better 

service users in polarized neutron scattering. 

The break from user operations during the recent outage 

provided an opportunity to develop and establish an EPR 

(electron paramagnetic resonance) measurement facility used 

to determine the 3

He polarization by measuring the shift in the 

alkali metal’s EPR frequency in the magnetic field arising from 

the 3

He magnetization. During the EPR measurement, the 

intensity of a collimated portion of the optical pumping laser 

beam passing through the center of the 3

He cell is monitored 

by a photodiode. This development has been very successful 

and in tests of wide-angle cells for MACS, we have found the 

3

He polarization results from EPR agree with the neutron-based 

values to within 1 %. 

There is a sustained drive to make the hardware and software 

used to control 3

He NSFs user-friendly, incorporating it into 

the instrument software. Continuing the previous development 

of the 3

He nuclear magnetic resonance (NMR) hardware and 

software for use on specific beam-lines, a universal method has 

been developed for NMR on all instruments using 3

He NSFs. 

Taking a modular approach, integrated hardware and software 

resides on a dedicated 3

He NMR computer and communicates 

with neutron instrument computers via a mini-PYTHON 

server. The software can control several free induction decay 

(FID) measurements and 3

He adiabatic fast passage (AFP) based 

spin flipping for both the polarizer and analyzer. The integrated 

device is user-friendly so that the instrument scientist or user can 

handle the complicated 3

He NMR flipper just like a conventional 

neutron spin flipper. The 3

He flipping information such as time 

stamps, number of flips, and the state of the 3

He spin is recorded 

for use by polarization efficiency correction software. 

During the year significant improvements in the 3

He 

polarization-flipping efficiency have been realized. Using 

an amplitude-modulated radio-frequency (RF) field when 

performing a frequency-sweep AFP NMR for 3

He spin flipping, 3

He polarization losses of 3x10-5 per flip for a magnetically 

shielded solenoid and 1x10-5 per flip for a magic box on the 

beam-lines have been achieved. The enhanced 3

He spinflipping capability for the magic box is a particular success and 

provides over one order of magnitude improvement in 3

He spin 

flipping efficiency for the solenoid compared to the constant 

RF field scheme. This amplitude-modulated RF scheme has 

been integrated into the NMR software for routine use on every 

instrument. 

Significant efforts have been made to advance polarized neutron 

instrumentation for each instrument class. The aim is to 

improve the polarized neutronic performance and detection 

efficiency for magnetic materials. For BT-7, one of the most 

important advances was to develop polarized inelastic neutron 

instrumentation. Building on the success of the polarized 

inelastic experiments just before the long shutdown in 2011 

[2], a re-optimized setup for BT-7 polarized beam for both the 

vertical field (P perpendicular to Q) and horizontal configuration 

(P parallel to Q) has been designed. Successful development 

of automated and nearly lossless (on the order of 10-5 per flip) 3

He spin flipping capability on the beam line as described 

above is essential for the new polarized beam setup. To achieve 

automated neutron spin control, it is necessary to have one 

adiabatic p/2 spin rotation for P perpendicular to Q and three 

adiabatic p/2 spin rotations for P parallel to Q. Ultra-compact 

spin rotation devices using permanent magnets and magnetic 

coils have been designed, which fit the constrained space on 

the BT-7 spectrometer. Simulations indicate that these spin 

rotation devices allow for efficient spin transport up to 50 meV. 

The new design of the spin rotation devices has also improved 

the relaxation time of the 3

He analyzer from 220 h to 330 h for 

a cell with an intrinsic relaxation time of 390 h. Optimization 

of the polarizer is in progress. Since flipping the 3

He spin on 

the order of every minute on the beam-line is a completely 

new development, tests are still required of the reliability and 

stability of the fast-3

He-spin-flipping scheme for both the 

polarizer and analyzer. The new design of the entire polarized 

beam instrumentation will significantly improve the long-term 

provision of a polarized beam setup on BT-7 and increase the 

reliability of operation of polarized beam experiments. 

For the SANS instruments, major improvements in polarization 

analysis have been made, which are important for scientific 

research at the forefront of nanomagnetism and other condensed 

matter applications. By improving the magnetic shielding of 

the 1.6 T electromagnet and developing a double-shielded 

solenoid, a higher sample field can now be provided as well as 

54 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
higher maximum Q. The modified electromagnet is available for 

SANS and possibly also reflectometry experiments and provides a 

transverse horizontal field for the sample. The magnetic shielding 

is important for efficient spin transport and for improving the 

lifetime of the 3

He analyzer cells. A double-shielded solenoid 

has been developed for improving the maximum Q range 

and the lifetime of the 3

He analyzer cells. Extensive polarized 

beam tests on SANS have confirmed that an adiabatic p/2 spin 

rotation from transverse horizontal (sample) to longitudinal (3

He 

analyzer) can be achieved even when the 3

He analyzer solenoid is 

only 10 cm (gap) away from the magnet. 

Finally, substantial improvements have been made in all aspects 

of the MACS polarized beam apparatus. Most notable is the 

success in fabricating wide-angle cells blown from GE180 glass 

that provide the required 110 degrees of angular coverage. The 

cells have yielded 3

He polarizations of 75 % and relaxation 

times longer than 100 h. Additional RF shielding and use of 

an amplitude-modulated RF frequency sweep for adiabatic fast 

passage NMR have reduced 3

He polarization loss to 0.03 % per 

flip for the polarizer and 0.006 % per flip for the analyzer. Full 

testing of the new apparatus will await the re-commissioning of 

MACS at its new location at BT-9. 

Sample Environment 

During the NCNR outage, sample environment and laboratory 

staff focused on maintenance and repair projects seeking to 

provide reliable equipment and facilities at the restart of Facility 

research activities. Overhaul of the entire fleet of bottom-loading 

closed-cycle refrigerators was completed. The 10 T cryogen-free 

magnet was outfitted with a cryogen-free variable-temperature 

insert and is now being used for experiments. Cryostat sample 

sticks were repaired and refurbished with the addition of 

overpressure devices and concentricity spacers. New capabilities 

include the development and preliminary testing of a computercontrolled gas-loading rig to support research across a range of 

areas including hydrogen storage, hydrate clathrate, and zeolite 

systems. 

The outage period also provided opportunity to fit out a new 

sample preparation laboratory for users. This laboratory vaunts a 

new wet glove box, ovens, and a microscope along with standard 

equipment and supplies necessary for sample preparation. New 

Dynamic Light Scattering and UV-VIS sample characterization 

apparatuses has also been installed and are ready for use—more 

information can be found in the CHRNS section (pp. 60-63). 

Data Acquisition 

The instrument suite was brought back on line with a 

controls package updated, rationalized, and standardized for 

manageability. All instrument computers are now enterprise 

managed using the Red Hat Enterprise distribution of Linux. 

Development of the New Instrument Control Environment 

(NICE) software system has followed the project plan initiated 

last year and successfully completed an alpha version which was 

deployed for testing on the pre-staged 10 m SANS in March 

2012. The alpha release, which includes only core features 

required for instrument control and data acquisition, has since 

been deployed in triple-axis mode on BT-4 and on a simulated 

neutron spin echo spectrometer. 

Data Analysis 

In the last decade, the Data Analysis and Visualization 

Environment (DAVE) project has been the primary vehicle 

through which software support has been provided for the 

inelastic instruments at the NCNR. Staff members at the 

NCNR and visiting research scientists use the software for 

various purposes including experiment planning, data reduction, 

visualization and data analysis. Although DAVE is fully 

functional, developers and instrument scientist continue to 

maintain and extend the software suite to accommodate user 

requests, changes to neutron scattering instrumentation or 

to take advantage of new techniques in software engineering. 

This brief report highlights examples of recent developments in 

reduction, visualization and analysis in the project, further details 

can be found at http://www.ncnr.nist.gov/dave/. 

Work on the initial phase of new data reduction modules for 

MACS and BT-7 are now complete. These two instruments 

represent the state-of-the-art in triple axis spectroscopy and 

hence require appropriate software that allows the scientists to 

fully explore the data generated from them. BT-7 and MACS 

respectively make use of a multichannel detector and a multidetector system and hence enable sophisticated scans to be 

performed in more than one independent variable. Furthermore, 

when multiple scans are grouped, volumetric data are produced. 

The challenge for the data reduction software is to automate 

the conversion of the raw data into physical units, taking into 

account instrument calibration parameters and, in the case of 

multiple files, stitching the data so that overlapping points are 

appropriately handled. The software supports single crystal or 

powder samples measured in either diffraction or inelastic mode. 

For BT-7, there is also a raw view mode that serves as a flexible 

tool for examining the data to look for patterns which, for 

example, can help the instrument scientist determine whether the 

instrument is operating as expected. 

As mentioned earlier, in most cases, the data produced by these 

instruments can be a function of more than two independent 

variables (volume data) and the DAVE Mslice tool is very 

effective at visualizing such data and performing basic analysis. 

A new feature in Mslice makes it even easier to perform planar 

slices of volumetric data and cuts of planar data. Using mouse 

controls, it is now possible to interactively manipulate the plane 

of interest from a volume or the line of interest from a plane and 

Facility Development
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 55 
 

Facility Development 

FIGURE 3: Mouse controls, depicted by the green slab and rectangle in the two left plots, are used to quickly select a region of interest which is then 

extracted, processed and displayed as shown by the plots to the right The intensity is integrated along the width of the slab or rectangle

view the results instantaneously. These are illustrated in the 

Fig. 3 where the contour plot is a slice of data from the volume 

plot represented by the green slab and the line plot is a cut from 

the contour plot represented by the green rectangle. If the slab 

or the rectangle is manipulated using the mouse, the sliced or cut 

visualization is automatically updated. 

The Peak Analysis (PAN) module in DAVE enables modeling of 

experimental data. The user can either take advantage of builtin functions or specify custom analytical expressions using IDL. 

PAN uses the Levenberg-Marquardt (LM) least-squares fitting 

algorithm to optimize the parameters of the model. LM uses a 

gradient search procedure that is fast and works well as long as 

the problem domain with respect to the model parameters has 

a simple topology with a single minimum or that the starting 

point is in the neighborhood of the global minimum. In some 

cases therefore, LM may fail to converge to the best solution. For 

PAN to be used for more challenging problems, a new algorithm 

is being developed as an alternative to LM. The technique is a 

genetic algorithm known as differential evolution (DE). DE 

is a population based stochastic search approach. It makes 

use of mutation strategies to evolve from an initial population 

(trial solution) to future generations that provide a better 

solution to the problem. While the basic algorithm has been 

developed, there is still work to be done before it can be made 

generally available. Genetic algorithms are notoriously difficult 

to use because the choice of mutation strategy, and associated 

control parameter values, that can be employed is inherently 

problem dependent. Our goal is to try to create an automated 

environment that will be as seamless to use as the LM currently 

in PAN. Consequently, we are still working to automate 

the selection of mutation strategies using adaptive feedback 

techniques, fine tuning the convergence criteria and calculating 

uncertainties in the best fit model parameters. 

References 

[1] V. Thampy et al., Phys. Rev. Lett. 108,107002 (2012). 

[2] Discovery of a New Type of Magnetic Mode in 

YBa2Cu3O6+x , H.A. Mook,  J.W. Lynn, M.B. Stone, 

M.D. Lumsden, and A.D. Christianson, (submitted). 

56 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Serving the Science and Technology Community
 

T

he mission of the NIST Center for Neutron Research 

is to assure the availability of neutron measurement 

capabilities to meet the needs of U.S. researchers from 

industry, academia and from other U.S. government 

agencies. To carry out this mission, the NCNR uses several 

different mechanisms to work with participants from outside 

NIST, including a competitive proposal process, instrument 

partnerships, and collaborative research with NIST. 

Proposal System 

Most of the time on NCNR instruments is made available 

through a competitive, peer-review proposal process. The 

NCNR issues calls for proposals approximately twice a year. 

Proposals are reviewed at several different levels. First, expert 

external referees evaluate each proposal on merit and provide 

us with written comments and ratings. This is a very thorough 

process where several different referees review each proposal. 

Second, the proposals are evaluated on technical feasibility 

and safety by NCNR staff. Third, we convene our Beam Time 

Allocation Committee (BTAC) to assess the reviews and to 

allocate the available instrument time. Using the results of the 

external peer review and their own judgment, the BTAC makes 

recommendations to the NCNR Director on the amount of 

beam time to allocate to each approved experiment. Approved 

experiments are scheduled by NCNR staff members in 

consultation with the experimenters. 

The current BTAC members are: 

n Andrew Allen (NIST Ceramics Division) 

n Jeffrey Allen (Michigan Technological University) 

n Collin Broholm (Johns Hopkins University) 

n Leslie Butler (Louisiana State University) 

n Kushol Gupta (University of Pennsylvania) 

n Hye-Jung Kang (Clemson University) 

n Ramanan Krishnamoorti (University of Houston) 

n Valery Kiryukhin (Rutgers University) 

n Raul Lobo (University of Delaware) 

n Janna Maranas (The Pennsylvania State University) 

n Steven May (Drexel University) 

n Alan Nakatani (Dow Chemical Company) 

n Danilo Pozzo (University of Washington) 

n Stephan Rosenkranz (Argonne National Laboratory) 

n Lynn Walker (Carnegie-Mellon University) 

Partnerships 

The NCNR may form partnerships with other institutions to 

fund the development and operation of selected instruments. 

These partnerships, or “Participating Research Teams”, may have 

access to as much as 75 % of the available beam time on the 

instrument depending on the share of total costs borne by the 

team. A minimum of 25 % of the available beam time is always 

made available through the NCNR proposal program to all users. 

Partnerships are negotiated for a fixed period (usually three years) 

and may be renewed if there is mutual interest and a continued 

need. These partnerships have proven to be an important and 

effective way to expand the research community’s access to 

NCNR capabilities and have been very successful in developing 

new instruments. 

Collaboration With NIST 

Some time on all instruments is available to NIST staff in 

support of our mission. This time is used to work on NIST 

research needs, instrument development, and promoting the 

widespread use of neutron measurements in important research 

areas, particularly by new users. As a result of these objectives, 

a significant fraction of the time available to NIST staff is used 

collaboratively by external users, who often take the lead in the 

research. Access through such collaborations is managed through 

written beam time requests. In contrast to proposals, beam time 

requests are reviewed and approved internally by NCNR staff. 

We encourage users interested in exploring collaborative research 

opportunities to contact an appropriate NCNR staff member. 

Research Participation And 

Productivity 

The NCNR continued its strong record of serving the U.S. 

research community this year. Over the 2012 reporting year, 

1976 research participants benefited from use of the NCNR. 

(Research participants include users who come to the NCNR 

to use the facility as well as active collaborators, including 

co-proposers of approved experiments, and co-authors of 

publications resulting from work performed at the NCNR.) 

As the number of participants has grown, the number of 

publications per year has increased in proportion. The quality of 

the publications has been maintained at a very high level. The 

trend of the past few years, however, suggests that the number 

of participants and publications is beginning to saturate, as 

one might expect as the capacity of the facility is reached. The 

Expansion Initiative full-power reactor shutdown from April 

2011 to April 2012 temporarily reduced participant numbers, 

Serving the Science and Technology Community
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 57 
 

 

 

 

Panel Of Assessment
 2500 

The major organizational components of NIST are evaluated 2000 

Serving the Science and Technology Community


cold source upgrade 

In 2012 Research Participants were from 

14 NIST Divisions and Offices 

40 U.S. Government Laboratories 

149 U.S. Universities 

29 U.S. Corporations 

Expansion outage 4-11 to 4-12 Expansion outage 4-11 to 4-12

annually for quality and effectiveness by the National Research 

Council (NRC), the principal operating agency of both the 

National Academy of Sciences and the National Academy of 

Engineering. A panel appointed by the NRC last reported on 

the NIST Center of Neutron Research in March 2011. Their 

findings are summarized in a document that may be viewed 

online at http://www.nist.gov/director/nrc/upload/nr-panelResearch Participants 1500 

1000 

500 

0 

2011-final-report.pdf The panel members included Tonya Kuhl 

of the University of California, Davis (chair), Meigan Aronson , 

Stony Brook University, Frank Bates, University of Minnesota, 

Donald Engelmann, Yale University, Paul Fleury, Yale University, 

Christopher Gould, North Carolina State University, Peter 

Green, University of Michigan, Alan Hurd, Los Alamos National 

Laboratory, James Lee, Sandia National Laboratory, John 

Parise, Stony Brook University, and Sunil Sinha, University of 

California, San Diego. 

The Center For High Resolution 

Neutron Scattering (CHRNS) 

CHRNS is a national user facility that is jointly funded by the 

National Science Foundation and the NCNR. Its primary 

goal is to maximize access to state-of-the-art neutron scattering 

instrumentation for the research community. It operates six 

neutron scattering instruments at the NCNR, enabling users 

from around the nation to observe dynamical phenomena 

involving energies from ≈ 30 neV t ≈ 100 meV, and to obtain 

FIGURE 1: Research participants at the NCNR 1986 - 2012

as shown in Fig. 1. Increasing activity and productivity can be 

expected as the Expansion continues towards completion. 

2012 NCNR Proposal Program 

Two calls for proposals for instrument time were issued in 

the past year. We received 705 proposals, of which 354 were 

approved and received beam time. The oversubscription, i.e., 

the ratio of days requested on all proposals to the days available, 

was 2.3 on the average, but as high as 3.0 for specific instruments 

in one call. Proposal demand has grown constantly since the 

NCNR first began accepting proposals in 1991, and has doubled 

in the past ten years. The following table shows the data for 

several instrument classes. 

Instrument class Proposals Days 

requested 

Days 

allocated 

SANS and USANS 258 982 449 

Reflectometers 105 653 294 

Spectrometers 281 1909 788 

Diffraction 30 99 50 

Imaging 31 153 74 

Total 705 3796 1655 

structural information on length scales from 1 nm to ≈ 10 μm. 

A more detailed account of CHRNS activities may be found on 

pp 60-63 of this report. 

Partnerships For Specific Instruments

NG-7 SANS Consortium 

A consortium that includes NIST, the Industrial Partnership for 

Research in Interfacial and Materials Engineering (IPRIME) led 

by the University of Minnesota, and the ExxonMobil Research 

and Engineering Company, operates, maintains, and conducts 

NCNR Users Group 
 research at the NG-7 30 m SANS instrument. The consortium 

The NCNR Users Group (NUG) provides an independent 

forum for all facility users to raise issues to NCNR management, 

uses 57 % of the beam time on this instrument, with the 

remaining 43 % allocated to the general scientific community 

through the NCNR’s proposal system. Consortium members working through its executive officers to carry out this function. 

The current officers are Mark Dadmun (University of Tennessee, conduct independent research programs primarily in the area of 

large-scale structure in soft matter. For example, ExxonMobil chair), John Katsaras (Oak Ridge National Laboratory), Michel has used this instrument to deepen their understanding of the Kenzelmann (Paul Scherrer Institute, Switzerland), Despina underlying nature of ExxonMobil’s products and processes, Louca (University of Virginia), Dale Schaefer (University especially in the fields of polymers, complex fluids, and of Cincinnati), Lynn Walker (Carnegie-Mellon University), 

and Erik Watkins (University of California, Davis and ILL, 

Grenoble). The NUG plans to conduct its next election of 

officers in late 2012. 

petroleum mixtures. 

58 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
The nSoft Consortium 

Formed in August 2012, the nSoft Consortium allows member 

companies to participate with NIST in the development 

of advanced measurements of materials and manufacturing 

processes, and develop their own expertise in state-of-the-art 

measurement technologies to include in their analytical research 

programs. nSoft develops new neutron-based measurement 

science for manufacturers of soft materials including plastics, 

composites, protein solutions, surfactants, and colloidal fluids. 

Members receive access to leading expertise and training support 

in neutron technology and soft materials science at the NIST 

Center for Neutron Research, the NIST Polymers Division, and 

the University of Delaware. Contact: Ron Jones, nSoft Director, 

rljones@nist.gov, 301-975-4624. 

NIST / General Motors – Neutron 

Imaging 

An ongoing partnership and collaboration between General 

Motors and NIST continues to yield exciting results using 

neutron imaging.  Neutron imaging has been employed to 

visualize the operation of fuel cells and lithium-ion batteries 

for automotive vehicle applications.  Neutron imaging is an 

ideal method for visualizing both hydrogen and lithium, the 

fuel of electric vehicles engines.  These unique, fundamental 

measurements, provide valuable material characterizations that 

will help improve the performance, increase the reliability, and 

reduce the time to market introduction of the next generation 

electric car engines. The GM/NIST partnership is entitled to 

25 % of the time on the BT-2 Neutron Imaging Facility. 

Interagency Collaborations 

The Smithsonian National Museum of Natural History has 

had a productive 34 year partnership with the NCNR, during 

which time it has chemically analyzed over 43 100 archaeological 

artifacts by Instrumental Neutron Activation Analysis (INAA), 

drawing extensively on the collections of the Smithsonian, as 

well as on those of many other institutions in this country and 

abroad. Such chemical analyses provide a means of linking these 

diverse collections together in order to study continuity and 

change involved in the production of ceramic and other artifacts. 

The Center for Food Safety and Applied Nutrition, U.S. Food 

and Drug Administration (FDA), directs and maintains a multilaboratory facility at the NCNR that provides agency-wide 

analytical support for food safety and food defense programs. 

Neutron activation (instrumental, neutron-capture promptgamma, and radiochemical), x-ray fluorescence spectrometry, 

and low-level gamma-ray detection techniques provide diverse 

multi-element and radiological information about foods 

and related materials. Current studies include validation of 

swordfish in-house reference material, revalidation of cocoa 

powder in-house reference material, measuring cesium levels in 

soil to study cesium uptake behavior into food products, rapid 

screening of food for dangerous levels of toxic elements (arsenic, 

cadmium, mercury, and lead), and optimizing neutron activation 

procedures for determination of arsenic and silver in foods and 

iodine in dietary supplements. 

Serving the Science and Technology Community
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 59 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Center for High Resolution Neutron Scattering (CHRNS)


The Center for High Resolution Neutron Scattering 

(CHRNS) 

T

he Center for High Resolution Neutron Scattering 

is a national user facility that is jointly funded by the 

National Science Foundation through its Division of 

Materials Research (grant number DMR-0944772), 

and by the NCNR. The primary purpose of this partnership 

is to maximize access to state-of-the-art neutron scattering 

instrumentation for the research community using the NCNR’s 

proposal system. Proposals to use the CHRNS instruments 

are critically reviewed on the basis of scientific merit and/or 

technological importance. 

The core mission of CHRNS is fourfold: (i) to develop and 

operate neutron scattering instrumentation, with broad 

application in materials research, for use by the general scientific 

community; (ii) to promote the effective use of the CHRNS 

instruments by having an identifiable staff whose primary 

function is to assist users; (iii) to conduct research that advances 

the capabilities and utilization of CHRNS facilities; and (iv) 

to contribute to the development of human resources through 

educational and outreach efforts. 

Scattering Instruments and Research 

During FY 2012, CHRNS supported operation of the following 

instruments: 

n the NG-3 30 m Small Angle Neutron Scattering (SANS) 

instrument, 

n the Ultra-Small Angle Neutron Scattering (USANS) 

instrument, 

n the Spin-Polarized Inelastic Neutron Scattering (SPINS) 

spectrometer, 

n the Multi-Angle Crystal Spectrometer (MACS), 

n the Disk Chopper Spectrometer (DCS), 

n the High Flux Backscattering Spectrometer (HFBS), and 

n the Neutron Spin-Echo (NSE) spectrometer. 

The small angle scattering instruments together provide structural 

information over length scales from ≈ 1 nm to ≈ 10 μm. The 

spectrometers collectively yield dynamical information over time 

scales from ≈ 3×10-14 s to ≈ 10-7 s (energy scales from ≈ 100 meV 

to ≈ 30 neV). These wide ranges of accessible distances and times 

support a very diverse scientific program, allowing researchers 

in materials science, chemistry, biology, and condensed matter 

physics to investigate materials such as polymers, metals, 

ceramics, magnetic materials, porous media, fluids and gels, and 

biological molecules. 

In the most recent Call for Proposals (call 29), 209 proposals 

requested CHRNS instruments, and 122 of these proposals 

received beam time. Of the 1070 days requested for the CHRNS 

instruments, 503 were awarded. Corresponding numbers for 

all instruments were 320 proposals received, 201 proposals 

approved, 1723 days requested, and 842 days awarded. Roughly 

half of the users of neutron scattering techniques at the NCNR 

use CHRNS-funded instruments, and more than one third 

of NCNR publications (see the “Publications” section on 

p. 66), over the current one-year period, are based on research 

performed using these instruments. This reports contains several 

highlights on CHRNS publications (pp. 66-85) In 2012 more 

than 25 Ph.D. dissertations were completed using results from 

CHRNS-sponsored instruments. 

Scientific Support Services 

The NCNR Sample Environment team provides users the 

equipment and training required to make measurements in 

special conditions of temperature, pressure, magnetic field, and 

fluid flow. The team recently acquired new equipment to benefit 

and expand these options: 

n three new bottom-loading closed cycle refrigerators (CCRs) 

that rapidly cool to 4 K, 

n an attachment for a CCR that can operate from 25 K to 800 K, 

n a new rheometer for uSANS that has the appropriate height 

for the instrument and is compatible with the existing SANS 

rheometer, and 

n three 6 kbar and three 10 kbar high pressure cells. 

During the outage from April, 2011 through February, 2012 the 

team undertook several projects to ensure that properly working 

equipment was ready to meet the needs of CHRNS users at 

startup. Some of these projects are listed below. 

n	 New variable-temperature inserts were installed and tested in 

the 10 T magnet. This equipment has since been successfully 

used for experiments approved by the Beam Time Allocation 

Committee (BTAC). 

n	 Preparations for re-commissioning the 11.5 T magnet and 

dilution refrigerator have been completed; installation of the 

new Intelligent Gas Handling System is imminent. 

n	 Cryostats have been inspected and/or refurbished to ensure 

optimal performance. 

60 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
 

 

 

 

 

 

n	 All of the bottom-loading and top-loading CCRs were 

inspected, new sensors installed, cold heads refurbished, 

systems tested, and other measures taken to ensure that they 

are fully functional. 

n	 Sample sticks were refurbished. Concentricity spacers and 

over-pressure safety systems were added to the sticks. The staff 

also assured the operation of wires, sensors and heaters. 

n	 The sample environment team and lab personnel worked with 

the NCNR staff to recover sample cans stored in lockers that 

were then added to the general supply available to users. 

n	 The team investigated temperature relaxation and 

equilibration behavior within the range of 5 K to 300 K in 

a variety of environments, samples and sample cells used on 

NCNR instruments to provide much-needed information. 

n	 A new gas loading rig was built to improve capabilities to 

perform gas adsorption studies. 

n	 A new humidity cell for SANS and reflectometry experiments 

is being prepared for users. New hardware and software are 

included in the improvements. 

NCNR’s user lab support staff ’s Kim Tomasi checks out a Barska digital 

microscope

The NCNR offers well-equipped and well-supplied laboratories 

for CHRNS users to prepare samples in a safe environment. 

NCNR’s Sarah Parks and Juscelino Leão lower the 10 T magnet into the 

DCS sample well

Laboratory staff members have developed training materials 

and provide regular advice to users as needed. To meet 

users’ demands, and to address the future growth of the user 

community, the NCNR has acquired new equipment, including 

a Dynamic Light Scattering system and UV-VIS spectrometer, 

and expanded laboratory space. 

The new users’ chemical laboratory was completed before 

the reactor startup. This laboratory features a wet glove box, 

fume hood, and vacuum ovens. During the shutdown all the 

user laboratories were readied with equipment and space, and 

restocked with supplies. 

Education and Outreach 

This year the Center for High Resolution Neutron Scattering 

sponsored a variety of educational programs and activities 

tailored to specific age groups and professions. The annual 

summer school, held June 18-23, was entitled “Summer School 

on Methods and Applications of Small Angle Neutron Scattering, 

Neutron Reflectivity and Spin Echo”. Thirty two graduate 

and postdoctoral students from 15 states and 23 universities 

participated in the school. Lectures, research seminars and 

2012 NCNR summer school participants and staff . 

The Center for High Resolution Neutron Scattering (CHRNS)
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 61 
The Center for High Resolution Neutron Scattering (CHRNS)
 

2012 SURF students and NCNR staff gather for a traditional group photo

hands-on instruction on data reduction and analysis techniques 

were highlighted for a wide variety of neutron measurement 

techniques. The guest lecturers were Prof. Bryan Vogt from the 

University of Akron and Dr. Hideki Seto from KEK, Japan. The 

evaluations were excellent and student feedback was very positive. 

As part of its expanding education and outreach effort, CHRNS 

offers to university-based research groups with BTAC-approved 

experimental proposals the opportunity to request travel 

support for an additional graduate student to participate in 

the experiment. This support is intended to enable prospective 

thesis students, for example, to acquire first-hand experience 

with a technique that they may later use in their own research. 

Announcements of this program are sent to all of the university 

groups whose experimental proposals receive beam time from 

the BTAC. Recipients of the announcement are encouraged to 

consider graduate students from under-represented groups for 

this opportunity. The program is also advertised on the NCNR’s 

website at http://www.ncnr.nist.gov/outreach.html. 

As in previous years, CHRNS participated in NIST’s Summer 

Undergraduate Research Fellowship (SURF) program. In 2012 

CHRNS hosted 10 SURF students. The students participated in 

areas such as thin-film deposition, x-ray characterization, studies 

of biological samples and the rheological properties of polymers, 

diffraction studies of magnetic materials and metal organic 

frameworks, web-based data reduction techniques, and reactor 

control systems development. They presented their work at the 

NIST SURF colloquium. At least four papers co-authored by a 

former SURF student, and one with a SHIP student (see below), 

were published in the reporting period. 

The Summer High school Intern Program (SHIP) was started in 

2008 with the participation of Vikas Bhatia from Gaithersburg 

High School (MD). Bhatia returned and was joined by Pavan 

Bhargava from Poolesville High School (MD) the following 

summer, and both students, now in college, returned as SURF 

SHIP student Priyanka Patel presents her work with NCNR’s William Ratcliff 

on calculating neutron structure factors on the web . 

students in 2010, 2011 and 2012. The SHIP program is now 

NIST-wide, and this year we had seven students from high 

schools in Maryland and Virginia. The students worked on such 

projects as web-based data reduction, studies of the magnetic 

properties of defect dicubane lanthanide clusters, and optimizing 

the smoothness of thin film samples. The results of the students’ 

summer investigations were highlighted in a NIST-wide poster 

session in early August. 

NCNR initiated a Research Experiences for Teachers (RET) 

program in the summer of 2010. Wootton High School teacher 

Michael Thompson (Montgomery County, MD) was selected 

for the program for the summer of 2012. He collaborated with 

NCNR’s Joe Dura and SURF student Pavan Bhargava on a 

project involving thin carbon films for battery and fuel cell 

applications. 

The annual Summer Institute for Middle School Science 

Teachers brings middle school science teachers to NIST for 

two weeks in order to give them a better understanding of the 

scientific process. In 2012 the Institute included teachers from 

Maryland, Florida, South Carolina, and New York. Each year, 

62 N A T I O N A L I N S T I T U T E O F S T A N D A R D S A N D T E C H N O L O G Y – N I S T C E N T E R F O R N E U T R O N R E S E A R C H 
 

 

 

 

 

 

In the RET program, Wootton High School teacher Michael Thompson 

(right) worked on carbon-based thin films for fuel cells and batteries with 

NCNR’s Joe Dura

CHRNS hosts the teachers for a one-day introduction to neutron 

scattering with a presentation that describes how neutrons are 

produced and how they are used to improve our understanding 

of materials at the atomic scale. Having toured the neutron guide 

hall, and having seen several neutron instruments, the teachers 

learn about the types of experiments performed at the NCNR. 

To bring home projects suitable for middle school students, they 

then learn how to grow crystals of “alum” (hydrated aluminum 

potassium sulfate), and how to make “shake gels”. Throughout 

the day, the teachers have the opportunity to interact with staff 

members and SURF students. The feedback from the teachers 

is consistently positive, and their comments help to improve the 

CHRNS program. 

Elementary, Middle, and High School Activities 

n As part of NIST’s activities for the annual “Take Your 

Daughters and Sons to Work Day”, CHRNS staff gave a 

presentation on what neutrons can do and offered a tour of 

the facility. The children, whose ages ranged from 12 to 15 

years old, enjoyed watching the “Neutron Mouse Trap” (which 

demonstrates a “chain reaction” with mouse traps and ping 

pong balls). 

n 15 tours for Middle School, High School, and University 

students were offered. 

n “Adventures in Science” is a hands-on science program for 

middle school students with classes in physics, chemistry, 

computers, biology, astronomy, etc., taught by scientists, 

engineers, and technical professionals. Classes meet for about 

two hours on Saturday mornings from October through 

March. NCNR’s Dan Neumann led a class this year. 

n Boy Scouts Nuclear Science Merit Badge - The NCNR and 

CHRNS staff developed a program to help Boy Scout troops 

around the NIST area earn their merit badge in nuclear science. 

n Montgomery County, MD School System - CHRNS staff 

members gave talks at local schools, teaching students about 

neutrons and materials studies at the NCNR, from making 

ice cream with liquid nitrogen (small crystals) to making 

“slime” using glue, water and sodium borate. Staff also served 

as judges at local science fairs. NCNR’s Yamali Hernandez is 

an advisor to the Montgomery County Board of Education’s 

Math and Science Curriculum Committee. 

n USA Science Festival - NCNR staff members in conjunction 

with scientists from the National High Magnetic Field 

Laboratory were in charge of one of the NSF booths at the 

USA Science Festival in Washington, DC. 

Summer Institute for Middle School Science Teachers assemble on the “dance floor” of the NSE instrument during a tour

The Center for High Resolution Neutron Scattering (CHRNS)
 

2012 A C C O M P L I S H M E N T S A N D O P P O R T U N I T I E S 63 
2012 Awards
 

2012 Awards
 

NCNR’s Jeff Lynn received the Presidential 

Rank Award of Distinguished Senior 

Professional. This prestigious honor recognizes 

individuals with an exceptional record of 

achieving major program goals and is consistently 

recognized nationally or internationally as a 

leader in a field. Jeff has developed and applied triple-axis 

neutron spectroscopy to many areas of condensed matter 

physics, with multiple contributions to the understanding of 

high-temperature superconductors, colossal magneto-resistance 

in materials, and magnetism across a wide range of crystalline 

solids. Such materials are fundamentally important to present 

and future technologies. 

NCNR’s Craig Brown is one of this year’s 

recipients of the Arthur S. Flemming Award 

honoring outstanding federal employees. He 

was recognized “For his seminal contributions 

to our understanding of new materials suited 

for hydrogen energy storage in next-generation, 

clean automobiles.” 

NCNR’s John Barker, Paul 

Butler, and James Moyer 

have received NIST’s 

Jacob Rabinow Applied 

Research Award. They are 

being recognized “For the 

design, development, and 

stewardship of USANS: An ultra-high resolution, small-angle, 

neutron-scattering instrument.” 

Thomas Gentile, of NIST’s Ionizing Radiation 

Division at the NCNR, received NIST’s Allen 

V. Astin Award for Measurement in Science. 

He was recognized “For excellence, innovation, 

and leadership in polarized 3

He.” 

NCNR’s Julie Borchers was elected a Fellow 

of the Neutron Scattering Society of America. 

She was recognized “For insightful neutron 

investigations of magnetic materials, particularly 

interlayer exchange interactions phenomena in 

magnetic thin films and superlattices”. 

Cindi Dennis, NIST 

Metallurgy Div., along 

with Julie Borchers 

and Andrew Jackson of 

the NCNR received the 

NIST Bronze Medal. 

They were recognized for 

“showing complete tumor regression in 75 % of cancerous mice 

occurs only after hyperthermia treatment using magnetically – 

interacting nanoparticles.” 

NCNR’s Tanya Burke has received the NIST 

Bronze Medal. She is being recognized “For 

administrative and technical leadership in the 

execution of critical, time-sensitive facility 

modifications supporting the NCNR 

expansion project.” 

NCNR’s Polly McCarty has received the 

Organizational Award for Safety. She was 

recognized “in recognition of her efforts as 

part of the Engineered Nanoparticle Safety 

Committee in helping to ensure a safe 

working environment for nanoparticle 

research here at NIST.” 

NCNR’s Wendy Queen received first place of 

Sigma Xi’s Annual Post-doc Poster Presentation 

in the area of Materials for her poster entitled 

“Reducing energy costs of industrial gas 

separations using metal-organic framework 

based solid adsorbents.” Wendy is now a 

staff member at the Molecular Foundry at Lawrence Berkley 

National Laboratory. 

Steve DeCaluwe, post-doc at the NCNR, 

received first place for Sigma Xi’s annual 

NIST Post-doc Poster Presentation in the 

area of Chemistry for his poster titled “In 

situ neutron reflectometry for the direct 

measurement of cyclic and evolving structures 

in the lithium battery solid electrolyte interphase.” Steve is now 

an Assistant Professor at the Colorado School of Mines. 

NCNR’s Ken Qian received second place 

for Sigma Xi’s annual NIST Post-doc Poster 

Presentation in the area of Materials, for 

his poster entitled “Probing the interaction 

and structural arrangement of medicinal 

compounds confined in novel, amorphous 

drug delivery systems.” 

64 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
Prof. Samuel Werner of NIST and University 

of Missouri has been selected as a Fellow of 

the Neutron Scattering Society of America 

“For elegant neutron experiments contributing 

to the understanding of quantum physics and 

for his sustained efforts to promote neutron 

science.” Sam was also recognized with an award by the NSSA 

as one of its founders for exceptional service to the neutron 

community. 

Charles Glinka was elected a Fellow of the 

Neutron Scattering Society of America, 

recognized “For development and operation of 

world-class capabilities for small angle neutron 

scattering in America.” Glinka retired from the 

NCNR and is currently a guest researcher. 

Antony Van Dyk and Alan 

Nakatani of Dow Coatings 

Materials have been selected 

as the winner of the American 

Coatings Award 2012 for the 

best paper entitled “Shear Rate 

Dependent Structure of Polymer Stabilized TiO2

 Dispersions” 

which highlights their work using USANS (ultra-high resolution 

small angle neutron scattering) at the NCNR to understand the 

interaction of TiO2

 slurries under shear. Nakatani and Van Dyk 

have long championed the utility of the USANS technique for 

improving understanding of coatings. 

Prof. Robert J. Cava of Princeton University 

received the Royal Society of Chemistry’s 

Stephanie L. Kwolek Award “For outstanding 

contributions to the understanding of the 

electronic structure and magnetic properties of 

solid state inorganic materials.” Prof. Cava was 

also selected as a Fellow of the Neutron Scattering Society of 

America “For outstanding applications of neutron diffraction to 

the understanding of complex materials, and advocacy for the 

field, particularly among young scientists.” He has published 

more than 100 papers containing neutron data from the NCNR. 

Prof. Matt Helgeson of UC Santa Barbara 

has been named a Distinguished Young 

Rheologist by TA Instruments. Helgeson was 

invited to talk on “Gelable Gels: Rheology 

of Soft Nanocomposites from Crosslinkable, 

Thermoresponsive Emulsions” at the TA 

Instruments Annual User Meeting. His work on soft matter is 

featured in this issue on p. 36. 

Prof. Rachel Segalman of the University 

of California, Berkeley won the 2012 John 

H. Dillon Medal “For fundamental and 

technological contributions to the field of 

polymer science and engineering, especially in 

the area of rod-coil block copolymers.” Prof. 

Segalman’s group are users of the NCNR. 

Prof. Sankar Nair of Georgia Tech, former 

NCNR post-doc, was selected for 2012 

American Institute of Chemical Engineers 

Separations Division Fractionation Research, 

Inc./John G. Kunesh Award and presented an 

invited lecture at the AIChE meeting entitled 

“Metal-Organic Framework (MOF) Materials and Membranes 

for Molecular Separations.” 

Dr. Guangyong Xu of Brookhaven National 

Laboratory, a frequent collaborator and user of 

the facilities at the NCNR, was the recipient 

of the 2012 Science Prize from the Neutron 

Scattering Society of America “for his work 

on relaxor ferroelectrics that have provided 

new insights into the role of polar nano-regions in determining 

the extreme electromechanical properties of these materials.” 

Xu gave an invited talk on his work at the June 2012 American 

Conference on Neutron Scattering. 

Brett Guralnick, a graduate student at the 

University of Delaware working with Prof. 

Michael Mackay, was awarded an outstanding 

student poster prize by the Neutron Scattering 

Society of America at the June 2012 American 

Conference on Neutron Scattering for his 

presentation “In Situ Annealing Study of Organic Photovoltaic 

Morphology via Non-invasive Polarized Neutron Reflectivity”, 

which was based on measurements made at the NCNR. 

Jeffrey J. Richards, a graduate student working 

with Prof. Danilo Pozzo at the University of 

Washington, was awarded an outstanding 

student poster prize by the Neutron Scattering 

Society of America at the June 2012 American 

Conference on Neutron Scattering for his 

presentation “Structure and Properties of Porous Poly(3­

hexylthiophene) Gel Particles in Aqueous Dispersion”, which was 

based on measurements made at the NCNR. 

2012 Awards
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 65 
Publications
 

Publications: August 1, 2011 to July 31, 2012


 Abakumov, A.M., Tsirlin, A.A., Perez-Mato, J.M., Petřiček, 

V., Rosner, H., Yang, T., Greenblatt, M., “Spiral 

Ground State against Ferroelectricity in the Frustrated 

Magnet BiMnFe2O6,” Phys. Rev. B 83(21), 214402 

(2011). 

Alexander, M., Nieh, M.-P., Ferrer, M.A., Corredig, M., 

“Changes in the Calcium Cluster Distribution of 

Ultrafiltered and Diafiltered Fresh Skim Milk as 

Observed by Small Angle Neutron Scattering,” J. Dairy 

Res. 78, 349 (2011). 

Alvine, K.J., Tyagi, M., Brown, C.M., Udovic, T.J., Jenkins, 

T., Pitman, S.G., “Hydrogen Species Motion in 

Piezoelectrics: A Quasi-Elastic Neutron Scattering 

Study,” J. Appl. Phys. 111(5), 053505 (2012). 

[CHRNS] 

Anderson, D.L., Cunningham, W.C., “Analysis of FDA inhouse Food Reference Materials with Anticoincidence 

INAA,” J. Radioanal. Nucl. Chem., in press. 

Anderson, D.L., “Anticoincidence INAA Capabilities 

for Analysis of FDA Total Diet Study Seafoods,” J. 

Radioanal. Nucl. Chem., in press. 

Anderson, D.L., “INAA Study of Hg, Se, As, and Br 

Irradiation Losses from L-cysteine Treated and 

Untreated Reference Materials,” J. Radioanal. Nucl. 

Chem., in press. 

Angelova, L.V., Terech, P., Natali, I., Dei, L., Carretti, E., 

Weiss, R.G., “Cosolvent Gel-like Materials from 

Partially Hydrolyzed Poly(vinyl acetate)s and Borax,” 

Langmuir 27, 11671 (2011). 

Asada, M., Gin, P., Endoh, M.K., Satija, S.K., Taniguchi, 

T., Koga, T., “Directed Self-Assembly of Nanoparticles 

at the Polymer Surface by Highly Compressible 

Supercritical Carbon Dioxide,” Soft Matter 7, 9231 

(2011). 

Asada, M., Gin, P., Endoh, M.K., Satija, S.K., Koga, T., 

“Surface Segregation of Nanoparticles Driven by 

Supercritical Carbon Dioxide,” J. Phys.: Conf. Ser. 272, 

012013 (2011). 

Bai, M., Miskowiec, A., Hansen, F.Y., Taub, H., Jenkins, T., 

Tyagi, M., Diallo, S.O., Mamontov, E., Herwig, K.W., 

Wang, S.-K., “Study of Water Diffusion on Singlesupported Bilayer Lipid Membranes by Quasielastic 

Neutron Scattering,” Europhys. Lett. 98(4), 48006 

(2012). [CHRNS] 

Bailey, M.M., Kline, S.R., Anderson, M.D., Staymates, J.L., 

Berkland, C., “Chemically Modifiable Fluorinated 

Copolymer Nanoparticles for 19F-MRI Contrast 

Enhancement,” J. Appl. Polym. Sci. 126, 1218 (2012). 

[CHRNS] 

Balzar, D., “Coherency Strain and Dislocations in CopperRich-Precipitate Embrittled A710 Ferritic Steels,” Metal 

Mater Trans A.43A, 1462 (2012). 

Bao, W., Huang, Q.-Z., Chen, G.-F., Green, M.A., Wang, 

D.- M., He, J.-B., Qiu, Y.-M., “A Novel Large 

Moment Antiferromagnetic Order in K0.8Fe1.6Se2 

Superconductor,” Chin. Phys. Lett. 28(8), 086104-1 

(2011). 

Barsan, M.M., Butler, I.S., Gilson, D.F.R., Moyer, Jr., 

R. O., Zhou, W., Wu, H., Udovic, T.J., “Raman, 

FTIR, Photoacoustic-Infrared, and Inelastic Neutron 

Scattering Spectra of Ternary Metal Hydride Salts 

A2MH5, (A=Ca, Sr, Eu; Ir, Rh) and Their Deuterides,” 

J. Phys. Chem. A116, 2490 (2012). 

Behrouzi, R., Roh, J.H., Kilburn, D., Briber, R.M., 

Woodson, S.A., “Cooperative Tertiary Interaction 

Network Guides RNA Folding,” Cell 149, 348 (2012). 

Bhatia, V., Rodriguez, E.E., Butch, N.P., Paglione, J., Green, 

M.A., “Phase Separation and Superconductivity in 

Fe1+xTe0.5Se0.5,” Chem. Commun. 47, 11297 (2011). 

Bhatti, K.P., El-Khatib, S., Srivastava, V., James, R.D., 

Leighton, C., “Small-Angle Neutron Scattering Study 

of Magnetic Ordering and Inhomogeneity Across the 

Martensitic Phase Transformation in Ni50-xCoxMn40Sn10 

Alloys,” Phys. Rev. B 85(13), 134450 (2012). 

[CHRNS] 

66 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
Bloch, E.D., Queen, W.L., Krishna, R., Zadrozny, J.M., 

Brown, C.M., Long, J.R., “Hydrocarbon Separations 

in a Metal-Organic Framework with Open Iron(II) 

Coordination Sites,” Science 335, 1606 (2012). 

Bloch, E.D., Murray, L.J., Queen, W.L. , Chavan, S., 

Maximoff, S.N., Bigi, J.P., Krishna, R., Peterson, V.K., 

Grandjean, F., Long, G.J., Smit, B., Bordiga, S., Brown, 

C.M., Long, J.R., “Selective Binding of O2 over N2 in 

Redox- Active Metal-Organic Framework with Open 

Iron(II) Coordination Sites,” J. Am. Chem. Soc. 133, 

14814 (2011). 

Braisted, J., Schneider, E., O’Kelly, S., van der Hoeven, C., 

“Design of an Irradiation Facility with a Real-Time 

Radiation Effects Monitoring Capability,” Nucl. 

Instrum. Methods Phys. Res., Sect. A 660, 83 (2011). 

Cappelletti, R.L., “The Acceleration of a Neutron in a Static 

Electric Field,” Phys. Lett. A 376, 2096 (2012). 

Cappelletti, R.L., editor, “2011 NIST Center for Neutron 

Research Accomplishments and Opportunities,” NIST 

SP 1127 (2011). 

Chen, W., Xu, T., He, F., Wang, W., Wang, C., Strzalka, J., 

Liu, Y., Wen, J., Miller, D.J., Chen, J., Hong, K., Yu, 

L., Darling, S.B., “Hierarchical Nanomorphologies 

Promote Exciton Dissociation in Polymer/Fullerene 

Bulk Heterojunction Solar Cells,” Nano Lett. 11, 

3707 (2011). 

Chen, W., Wang, J.-Y., Zhao, W., Li, L., Wei, X., Balazs, 

A.C., Matyjaszewski, K., Russell, T.P., “Photocontrol 

over the Disorder-to-Order Transition in Thin Films 

of Polystyrene-block-poly(methyl methacrylate) 

Block Copolymers Containing Photodimerizable 

Anthracene Functionality,” J. Am. Chem. Soc. 133(43), 

17217 (2011). 

Cheng, X., Prask, H.J., Gnaeupel-Herold, T., Luzin, V., 

Fisher, J.W., “Neutron Diffraction Measurements for 

Residual Stresses in AL-6XN Stainless Steel Welded 

Beams,” in “Neutron Diffraction,” edited by Khidirov, 

I.(Intech Open Access Publisher, Manhattan, New 

York) Chap. 2, 25 (2012). 

Chi, S., Rodriguez-Rivera, J.A., Lynn, J.W., Zhang, C., 

Phelan, D., Singh, D.K., Paul, R., Dai, P., “Common 

Origin of the Two Types of Magnetic Fluctuations in 

Iron Chalcogenides,” Phys. Rev. B 84(21), 214407 

(2011). [CHRNS] 

Chiang, C.-C., Tsai, W.-C., Wang, L.-W., Hou, H.-C., Liao, 

J.-W., Lin, H.-J., Chang, F.-H., Kirby, B.J., Lai, C.-H., 

“(001) FePt Graded Media with PtMn Underlayers,” 

Appl. Phys. Lett. 99(21), 212504 (2011). 

Choi, D., Moon, J.H., Kim, H., Sung, B.J., Kim, M.W., 

Tae, G.Y., Satija, S.K., Akgun, B., Yu, C.-J., Lee, H.W., 

Lee, D.R., Henderson, J.M, Kwong, J.W., Lam, K.L., 

Lee, K.Y.C., Shin, K. “Insertion Mechanism of Cellpenetrating Peptides into Supported Phospholipid 

Membranes Revealed by X-ray and Neutron 

Reflection,” Phys. Rev. Lett., in press. 

Chou, S.G., Soper, A.K., Khodadadi, S., Curtis, J.E., 

Krueger, S., Cicerone, M.T., Fitch, A.N., Shalaev, E.Y., 

“Pronounced Microheterogeneity in a Sorbitol-Water 

Mixture Observed through Variable Temperature 

Neutron Scattering,” J. Phys. Chem. B 116, 4439 

(2012). [CHRNS] 

Chua, Y.S., Wu, H., Zhou, W., Udovic, T.J., Wu, G., 

Xiong, Z., Wong, M.W., Chen, P., “Monoammoniate 

of Calcium Amidoborane: Synthesis, Structure and 

Hydrogen- Storage Properties,” Inorg. Chem. 51, 

1599 (2012). 

Cicerone, M.T., Douglas, J.F., “β-Relaxation Governs Protein 

Stability in Sugar-Glass Matrices,” Soft Matter 8, 2983 

(2012). [CHRNS] 

Clarkson, C.R., Solano, N., Bustin, R.M., Bustin, 

A.M.M., Chalmers, G.R.L., He, L., Melnichenko, 

Y.B., Radliński, A.P., Blach, T.P., “Pore Structure 

Characterization of North American Shale Gas 

Reservoirs using USANS/SANS, Gas Adsorption, and 

Mercury Intrusion,” Fuel, in press. [CHRNS] 

Clarkson, C.R., Freeman, M., He, L., Agamalian, M., 

Melnichenko, Y.B., Mastalerz, M., Bustin, R.M., 

Radlinski, A.P., Blach, T.P., “Characterization of Tight 

Gas Reservoir Pore Structure using USANS/SANS and 

Gas Adsorption Analysis,” Fuel 95(1), 371 (2012). 

[CHRNS] 

Cooper, R.L., Alarcon, R., Bales, M.J., Bass, C.D., Beise, 

E.J., Breuer, H., Byrne, J., Chupp, T.E., Coakley, K.J., 

Dewey, M.S., Fu, C., Gentile, T.R., Mumm, H.P., 

Nico, J.S., O’Neill, B., Pulliam, K., Thompson, A.K., 

Wietfeldt, F.E., “A Gamma- and X-ray Detector for 

Cryogenic, High Magnetic Field Applications,” Nucl. 

Instrum. Methods Phys. Res., Sect. A, in press. 

Publications
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 67 
Publications
 

Copley, J.R.D., “Acceptance Diagram Calculations of the 

Performance of Neutron Removal Mirrors,” Nucl. 

Instrum. Methods Phys. Res., Sect. A 659, 403 (2011). 

Couet, A., Motta, A.T., Comstock, R.J., Paul, R.L., “Cold 

Neutron Prompt Gamma Activation Analysis, a Nondestructive Technique for Hydrogen Level Assessment 

in Zirconium Alloys,” J. Nucl. Mater. 425, 211 (2012). 

Cui, J., Lackey, M.A., Madkour, A.E., Saffer, E.M., 

Griffin, D.M., Bhatia, S.R., Crosby, A.J., Tew, G.N., 

“Synthetically Simple, Highly Resilient Hydrogels,” 

Biomacromolecules 13, 584 (2012). 

Curtis, J.E., McAuley, A., Nanda, H., Krueger, S., “Protein 

Structure and Interactions in the Solid State Studied by 

Small-Angle Neutron Scattering,” Faraday Discuss., in 

press. [CHRNS] 

Curtis, J.E., Nanda, H., Khodadadi, S., Cicerone, M., Lee, 

H.J., McAuley, A., Krueger, S., “Small-Angle Neutron 

Scattering Study of Protein Crowding in Liquid and 

Solid Phases: Lysozyme in Aqueous Solution, Frozen 

Solution, and Carbohydrate Powders,” J. Phys. Chem. 

B, in press. [CHRNS] 

Curtis, J.E., Raghunandan, S., Nanda, H., Krueger, S., 

“SASSIE: A Program to Study Intrinsically Disordered 

Biological Molecules and Macromolecular Ensembles 

using Experimental Scattering Restraints,” Comput. 

Phys. Commun. 183, 382 (2012). [CHRNS] 

Das, M.C., Xu, H., Wang, Z., Srinivas, G., Zhou, W., Yue, 

Y.-F., Nesterov, V.N., Qian, G., Chen, B., “A Zn4OContaining Doubly Interpenetrated Porous MetalOrganic Framework for Photocatalytic Decomposition 

of Methyl Orange,” Chem. Commun. 47, 11715 

(2011). 

Das, P., Rastovski, C., O’Brien, T.R., Schlesinger, K.J., 

Dewhurst, C.D., DeBeer-Schmitt, L., Zhigadlo, 

N.D., Karpinski, J., Eskildsen, M.R., “Observation 

of Well-Ordered Metastable Vortex Lattice Phases in 

Superconducting MgB2 Using Small-Angle Neutron 

Scattering,” Phys. Rev. Lett. 108(16), 167001 (2012). 

[CHRNS] 

Dee, D.R., Myers, B., Yada, R.Y., “Dynamics of 

Thermodynamically Stable, Kinetically Trapped, and 

Inhibitor-Bound States of Pepsin,” Biophys. J. 101, 

1699 (2011). [CHRNS] 

Dee, D.R., Yada, R.Y., “Neutron Scattering and the Folding 

and Dynamics of the Digestive Enzyme Pepsin,” 

Neutron News 23(2), 29 (2012). [CHRNS] 

Deka, U., Juhin, A., Eilertsen, E.A., Emerich, H., Green, 

M.A., Korhonen, S.T., Weckhuysen, B.M., Beale, 

A.M., “Confirmation of Isolated Cu2+ Ions in SSZ13 Zeolite as Active Sites in NH3-Selective Catalytic 

Reduction,” J. Phys. Chem. C 116, 4809 (2012). 

Delaire, O., Stone, M.B., Ma, J., Huq, A., Gout, D., Brown, 

C., Wang, K.F., Ren, Z.F., “Anharmonic Phonons and 

Magnons in BiFeO3,” Phys. Rev. B 85(6), 064405 

(2012). [CHRNS] 

de Souza, R.A., Staub, U., Scagnoli, V., Garganourakis, M., 

Bodenthin, Y., Huang, S.W., García-Fernández, M., 

Ji, S., Lee, S.H., Park, S., Cheong, S.-W., “Magnetic 

Structure and Electric Field Effects in Multiferroic 

YMn2O5,” Phys. Rev. B 84(10), 104416 (2011). 

Dhaubhadel, R., Rieker, T.P., Chakrabarti, A., Sorensen, 

C.M., “Synthesis of Silica Aerosol Gels via Controlled 

Detonation,” Aerosol Sci. Technol. 46, 596 (2012). 

Diallo, S.O., Azuah, R.T., Abernathy, D.L., Rota, R., 

Boronat, J., Glyde, H.R., “Bose-Einstein Condensation 

in Liquid 4

He Near the Liquid-Solid Transition Line,” 

Phys. Rev. B 85(14), 140505 (2012). 

Diao, Y., Helgeson, M.E., Siam, Z.A., Doyle, P.S., Myerson, 

A.S., Hatton, T.A., Trout, B.L., “Nucleation Under Soft 

Confinement: Role of Polymer-Solute Interactions,” 

Cryst. Growth Des. 12(1), 508 (2012). [CHRNS] 

Ding, L., Wang, C., Chu, L., Yan, J., Na, Y., Huang, Q., 

Chen, X., “Near Zero Temperature Coefficient of 

Resistivity in Antiperovskite Mn3Ni1-xCuxN,” Appl. 

Phys. Lett. 99(25), 251905 (2011). 

Dissanayake, S.E., Chan, C., Ji, S., Lee, J., Qiu, Y., Rule, 

K.C., Lake, B., Green, M., Hagihala, M., Zheng, 

X.G., Ng, T.K., Lee, S.-H., “Magnetic-field-Induced 

Instability of the Cooperative Paramagnetic State in 

ZnxCo4-x(OD)6Cl2,” Phys. Rev. B 85(17), 174435 

(2012). [CHRNS] 

68 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
Dufour, C., Fitzsimmons, M.R., Borchers, J.A., Laver, M., 

Krycka, K.L., Dumesnil, K., Watson, S.M., Chen, 

W.C., Won, J., Singh, S., “Nanometer-Size Magnetic 

Domains and Coherent Magnetization Reversal in 

a Giant Exchange Bias System,” Phys. Rev. B 84(6), 

064420 (2011). 

Dumas, R.K., Fang, Y., Kirby, B.J., Zha, C., Bonanni, V., 

Nogués, J., Åkerman, J., “Probing Vertically Graded 

Anisotropy in FePtCu Films,” Phys. Rev. B 84(5), 

054434 (2011). 

Dutton, S.E., Huang, Q., Tchernyshyov, O., Broholm, C.L., 

Cava, R.J., “Sensitivity of the Magnetic Properties of the 

ZnCr2O4 and MgCr2O4 Spinels to Nonstoichiometry,” 

Phys. Rev. B 83(6), 064407 (2011). 

Dutton, S.E., Kumar, M., Mourigal, M., Soos, Z.G., Wen, J.­

J., Broholm, C.L., Andersen, N.H., Huang, Q., Zbiri, 

M., Toft-Petersen, R., Cava, R.J., “Quantum Spin 

Liquid in Frustrated One-Dimensional LiCuSbO4,” 

Phys. Rev. Lett. 108(18), 187206 (2012). 

Eberle, A.P.R., Ortman, K., Baird, D.G., “Structure 

and Rheology of Fiber Suspensions,” in “Applied 

Polymer Rheology: Polymeric Fluids with Industrial 

Applications,” edited by Kontopoulou, M. (John Wiley 

& Sons, Inc., Hoboken, NJ) 4, 113 (2011). 

Eberle, A.P.R., Castañeda-Priego, R., Kim, J.M., Wagner, 

N.J., “Dynamical Arrest, Percolation, Gelation, and 

Glass Formation in Model Nanoparticle Dispersions 

with Thermoreversible Adhesive Interactions,” 

Langmuir 28, 1866 (2011). 

Eberle, A.P.R., Porcar, L., “Flow-SANS and Rheo-SANS 

Applied to Soft Matter,” Curr. Opin. Colloid Interface 

Sci. 17, 33 (2012). 

Ehlers, G., Huq, A., Diallo, S.O., Adriano, C., Rule, K.C., 

Cornelius, A.L., Fouquet, P., Pagliuso, P.G., Gardner, 

J.S., “Low Energy Spin Dynamics in the Spin Ice 

Ho2Sn2O7,” J. Phys.: Condens. Matter 24, 076005 

(2012). 

Espinal, L., Wong-Ng, W., Kaduk, J.A., Allen, A.J., Snyder, 

C.R., Chiu, C., Siderius, D.W., Li, L., Cockayne, 

E., Espinal, A.E., Suib, S.L., “Time-Dependent 

CO2 Sorption Hysteresis in a One-Dimensional 

Microporous Octahedral Molecular Sieve,” J. Am. 

Chem. Soc. 134, 7944 (2012). [CHRNS] 

Falus, P., Porcar, L., Fratini, E., Chen, W.-R., Faraone, A., 

Hong, K., Baglioni, P., Liu, Y., “Distinguishing the 

Monomer to Cluster Phase Transition in Concentrated 

Lysozyme Solutions by Studying the Temperature 

Dependence of the Short-Time Dynamics,” J. Phys.: 

Condens. Matter 24, 064114 (2012). [CHRNS] 

Faraone, A., Hong, K., Kneller, L.R., Ohl, M., Copley, 

J.R.D., “Coherent Dynamics of meta-Toluidine 

Investigated by Quasielastic Neutron Scattering,” J. 

Chem. Phys. 136(10), 104502 (2012). [CHRNS] 

Ferguson, P.P., Fleischauer, M.D., LaForge, J.M., Todd, 

A.D.W., Li, P., Dahn, J.R., “Studies of CoSn Grains in 

the Carbon Matrix Structure of Nanostructured TinCobalt-Carbon,” J. Alloys Compd., in press. [CHRNS] 

Fisher, B.M., Abdurashitov, J.N., Coakley, K.J., Gavrin, V.N., 

Gilliam, D.M., Nico, J.S., Shikhin, A.A., Thompson, 

A.K., Vecchia, D.F., Yants, V.E., “Fast Neutron 

Detection with 6

Li-Loaded Liquid Scintillator,” Nucl. 

Instrum. Methods Phys. Res., Sect. A 646, 126 (2011). 

Fitzgerald, P.A., Chatjaroenporn, K., Zhang, X., Warr, G.G., 

“Micellization of Monomeric and Poly-w-methacryloyloxyundecyltrimethylammonium Surfactants,” 

Langmuir 27, 11852 (2011). 

Ford, K.M., Konzman, B.G., Rubinson, J.F., “A More 

Informative Approach for Characterization of Polymer 

Monolithic Phases: Small Angle Neutron Scattering/ 

Ultrasmall Angle Neutron Scattering,” J. Anal. Chem. 

83, 9201 (2011). [CHRNS] 

Frontzek, M., Haraldsen, J.T., Podlesnyak, A., Matsuda, M., 

Christianson, A.D., Fishman, R.S., Sefat, A.S., Qiu, 

Y., Copley, J.R.D., Barilo, S., Shiryaev, S.V., Ehlers, 

G., “Magnetic Excitations in the Geometric Frustrated 

Multiferroic CuCrO2,” Phys. Rev. B 84(9), 094448- 1 

(2011). [CHRNS] 

Furdyna, J.K., Leiner, J., Liu, X., Dobrowolska, M., Lee, 

S., Chung, J.-H., Kirby, B.J., “Exchange Coupling 

in Magnetic Semiconductor Multilayers and 

Superlattices,” Acta Phys. Pol., A 5-6, 973 (2012). 

Gadipelli, S., Calizo, I., Ford, J., Cheng, G., Hight Walker, 

A.R., Yildirim, T., “A Highly Practical Route for LargeArea, Single Layer Graphene from Liquid Carbon 

Sources such as Benzene and Methanol,” J. Mater. 

Chem. 21, 16057 (2011). 

Publications
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 69 
NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH

Publications
 

Gardner, J.S., Ehlers, G., Diallo, S.O., “Neutron Studies 

of Tb2Mo2O7,” Chin. J. Phys. 50(2), 256 (2012). 

[CHRNS] 

Garg, S., Porcar, L., Hamill, A.C., Butler, P.D., Perez-Salas, 

U., “Response to “How Slow is the Transbilayer 

Diffusion (Flip-Flop) of Cholesterol?,”” Biophys. J. 

102(4), 947 (2012). [CHRNS] 

Gaulin, B.D., Gardner, J.S., McClarty, P.A., Gringras, M.J.P., 

“Lack of Evidence for a Singlet Crystal-Field Ground 

State in the Magnetic Pyrochlore Tb2Ti2O7,” Phys. Rev. 

B 84(14), 140402 (2011). [CHRNS] 

Gaulin, B.D., Gardner, J.S., “Experimental Studies of 

Pyrochlore Antiferromangnets,” in “Introduction to 

Frustrated Magnetism Materials, Experiments, Theory,” 

edited by Lacroix, C., Mendels, P., Mila, F. (Springer 

Berlin Heidelberg), Chap. 8, 177 (2011). [CHRNS] 

Gehring, P.M., “Neutron Diffuse Scattering in Lead-Based 

Relaxor Ferroelectrics and its Relationship to the UltraHigh Piezoelectricity,” J. Adv. Dielect. 2(2), 1241005 

(2012). [CHRNS] 

Gentile, T.R., Bass, C.D., Nico, J.S., Breuer, H., Farrell, 

R., “Magnetic Field Effects on Large Area Avalanche 

Photodiodes at Cryogenic Temperatures,” Nucl. 

Instrum. Methods Phys. Res., Sect. A 652, 520 (2011). 

Gentile, T.R., Bales, M., Arp, U., Dong, B., Farrell, R., 

“Response of Large Area Avalanche Photodiodes to Low 

Energy X-Rays,” Rev. Sci. Instrum. 83(5), 053105-1 

(2012). 

Glyde, H.R., Diallo, S.O., Azuah, R.T., Kirichek, O., Taylor, 

J.W., “Atomic Momentum Distribution and BoseEinstein Condensation in Liquid 4

He under Pressure,” 

Phys. Rev. B 84(18), 184506-1 (2011). 

Gnäupel-Herold, T.H., “A Software for Diffraction Stress 

Factor Calculations for Textured Material,” in 

“Advances in X-ray Analysis,” edited by Blanton, T., 

(60th Denver X-ray Conf. Proc., August 2011, Colorado 

Springs, CO) 55, 123 (2012). 

Gnäupel-Herold, T.H., “ISODEC: Software for Calculating 

Diffraction Elastic Constants,” J. Appl. Crystallogr. 45, 

573 (2012). 

Gnäupel-Herold, T.H., Creuziger, A.A., Iadicola, M., “A 

Model for Calculating Diffraction Elastic Constants,” J. 

Appl. Crystallogr. 45, 197 (2012). 

Gnäupel-Herold, T.H., “A Software for Diffraction Stress 

Factor Calculations for Textured Materials,” Powder 

Diffr. 27(2), 114 (2012). 

Gnäupel-Herold, T.H., Creuziger, A., Iadicola, M.A., “An 

Investigation of the Accuracy of Diffraction Stress 

Evaluation of Textured Materials,” in “Advances in 

X-ray Analysis,” edited by Blanton, T., (60th Denver 

X-ray Conf. Proc., August 2011, Colorado Springs, 

CO) 55, 128 (2012). 

Gnäupel-Herold, T.H., Creuziger, A.A., Iadicola, M., 

“Evolution of Anisotropic Stress Factors with Texture 

in the Biaxial Deformation of HSLA50 Steel,” in 

“Plasticity 2012,” edited by Khan, A., (International 

Symp. On Plasticity and its Current Appl. Conf. Proc., 

January 2012, Rio Grande, PR.), 13 (2012). 

Gu, Y., Wang, C., Russell, T.P., “Multi-Length-Scale 

Morphologies in PCPDTBT/PCBM Bulk-Heterojunction Solar Cells,” Adv. Energy Mater. 2, 683 (2012). 

Guidi, T., “Neutron Spectroscopy of Molecular 

Nanomagnets,” in “Molecular Cluster Magnets, 

Volume 3” edited by Winpenny, R. (World Scientific 

Series in NanoScience and Nanotechnology), Chap. 4, 

181 (2011). [CHRNS] 

Gupta, S., Dura, J.A., Freites, J.A., Tobias, D.J., Blasie, J.K., 

“Structural Characterization of the Voltage Sensor 

Domain and Voltage-gated K+

- Channel Proteins 

Vectorially-oriented within a Single Bilayer 

Membrane at the Solid/Vapor and Solid/Liquid 

interfaces via Neutron Interferometry,” Langmuir 

28(28), 10504 (2012). 

Habersberger, B.M., Bates, F.S., Lodge, T.P., “Hierarchical 

Microphase Separation in Bicontinuous Ternary 

Polymer Blends,” Soft Matter 8, 3429 (2012). 

Hammouda, B., “Small-Angle Scattering from Branched 

Polymers,” Macromol. Theory Simul. 21, 372 (2012). 

Hardy, G.J., Nayak, R., Munir Alam, S., Shapter, J.G., 

Heinrich, F., Zauscher, S., “Biomimetic Supported 

Lipid Bilayers with High Cholesterol Content Formed 

by α-helical Peptide-induced Vesicle Fusion,” J. Mater. 

Chem., in press. 

70 
He, L., Melnichenko, Y.B., Mastalerz, M., Sakurovs, R., 

Radlinski, A.P., Blach, T., “Pore Accessibility by 

Methane and Carbon Dioxide in Coal as Determined 

by Neutron Scattering,” Energy Fuels 26, 1975 (2012). 

[CHRNS] 

He, T., Wu, H., Wu, G., Wang, J., Zhou, W., Xiong, 

Z., Chen, J., Zhang, T., Chen, P., “Borohydride 

Hydrazinates: High Hydrogen Content Materials for 

Hydrogen Storage,” Energy Environ. Sci. 5, 5686 

(2012). 

He, Y., Zhang, Z., Xiang, S., Wu, H., Franczek, F.R., 

Zhou, W., Krishna, R., O’Keeffe, M., Chen, B., 

“High Separation Capacity and Selectivity of C2 

Hydrocarbons over Methane within a Microporous 

Metal-Organic Framework at Room Temperature,” 

Chem. Eur. J., 18 1901 (2012). 

Helgeson, M.E., Wagner, N.J., “Colloidal Interactions 

Mediated by End-adsorbing Polymer-Like Micelles,” 

J. Chem. Phys. 135(8), 084901 (2011). 

Helgeson, M.E., Moran, S.E., An, H.Z., Doyle, P.S., 

“Mesoporous Organohydrogels from Thermogelling 

Photocrosslinkable Nanoemulsions,” Nature Materials 

11(4), 344 (2012). [CHRNS] 

Helton, J.S., Stone, M.B., Shulyatev, D.A., Mukovskii, 

Y.M., Lynn, J.W., “Paramagnetic Spin Correlations in 

Colossal Magnetoresistive La0.7Ca0.3MnO3,” Phys. Rev. 

B 85(14), 144401 (2012). 

Helton, J.S., Singh, D.K., Nair, H.S., Elizabeth, S., 

“Magnetic Order of the Hexagonal Rare-Earth 

Manganite Dy0.5Y0.5MnO3,” Phys. Rev. B 84(6), 

064434 (2011). [CHRNS] 

Helton, J.S., Chen, Y., Bychkov, G.L., Barilo, S.N., 

Rogado, N., Cava, R.J., Lynn, J.W., “Evolution of 

the Commensurate and Incommensurate Magnetic 

phases of the S = 3/2 Kagome Staircase Co3V2O8 in an 

Applied Field,” J. Phys.: Condens. Matter 24, 016003 

(2012). 

Her, J.-H., Wu, H., Verdal, N., Zhou, W., Stavila, V., 

Udovic, T.J., “Structures of the Strontium and Barium 

Dodecahydro-closo-dodecaborates,” J. Alloys Compd. 

514, 71 (2012). 

Hoarfrost, M.L., Tyagi, M., Segalman, R.A., Reimer, J.A., 

“Proton Hopping and Long-Range Transport in the 

Protic Liquid [Im][TFSI], Probed by Pulsed-Field 

Gradient NMR and Quasi-Elastic Neutron Scattering,” 

J. Phys. Chem. B 116(28), 8201 (2012). [CHRNS] 

Hoarfrost, M.L., Tyagi, M.S., Segalman, R.A., Reimer, 

J.A., “Effect of Confinement on Proton Transport 

Mechanisms in Block Copolymer/Ionic Liquid 

Membranes,” Macromolecules 45, 3112 (2012). 

[CHRNS] 

Hong, K., Liu, Y., Porcar, L., Liu, D., Gao, C.Y., Smith, 

G.S., Herwig, K.W., Cai, S., Li, X., Wu, B., Chen, 

W.-R., Liu, L., “Structural Response of Polyelectrolyte 

Dendrimer Towards Molecular Protonation: The 

Inconsistency Revealed by SANS and NMR,” J. Phys.: 

Condens. Matter 24, 064116 (2012). 

Hong, L., Smolin, N., Lindner, B., Sokolov, A.P., Smith, J.C., 

“Three Classes of Motion in the Dynamic NeutronScattering Susceptibility of a Globular Protein,” Phys. 

Rev. Lett. 107(14), 148102 (2011). [CHRNS] 

Hong, L., Cheng, X., Glass, D.C., Smith, J.C., “Surface 

Hydration Amplifies Single-Well Protein Atom 

Diffusion Propagating into the Macromolecular Core,” 

Phys. Rev. Lett. 108(23), 238102 (2012). [CHRNS] 

Hopkins, A.R., Tomczak, S.J., Vij, V., Jackson, A.J., “Small 

Angle Neutron Scattering (SANS) Characterization 

of Electrically Conducting Polyaniline Nanofiber/ 

Polyimide Nanocomposites,” Thin Solid Films 520, 

1617 (2011). [CHRNS] 

Horkay, F., Cho, S.H., Tathireddy, P., Rieth, L., Solzbacher, 

F., Magda, J., “Thermodynamic Analysis of the 

Selectivity Enhancement Obtained by Using Smart 

Hydrogels that are Zwitterionic when Detecting 

Glucose with Boronic Acid Moieties,” Sensors and 

Actuators B 160, 1363 (2011). [CHRNS] 

Horkay, F., Basser, P.J., Hecht, A.-M., Geissler, E., 

“Hierarchical Organization of Cartilage Proteoglycans,” 

Macromol. Symp. 306-307, 11 (2011). [CHRNS] 

Horkay, F., Basser, P.J., Hecht, A.-M., Geissler, E., 

“Chondroitin Sulfate in Solution: Effects of Mono- and 

Divalent Salts,” Macromolecules 45, 2882 (2012). 

Publications
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 71 
Publications
 

Hu, N., Borkar, N., Kohls, D., Schaefer, D.W., 

“Characterization of Porous Materials Using Combined 

Small-Angle X-ray and Neutron Scattering Techniques,” 

J. Membr. Sci. 379, 138 (2011). [CHRNS] 

Huang, Q., Cai, J., Wu, H., He, Y., Chen, B., Qian, G., 

“A Robust Microporous Metal-Organic Framework 

Constructed from a Flexible Organic Linker for Highly 

Selective Sorption of Methanol over Ethanol and 

Water,” J. Mater. Chem. 22, 10352 (2012). 

Hudson, M.R., Queen, W.L., Mason, J.A., Fickel, D.W., 

Lobo, R.F., Brown, C.M., “Unconventional, Highly 

Selective CO2 Adsorption in Zeolite SSZ-13,” J. Am. 

Chem. Soc. 134, 1970 (2012). 

Hussey, D.S., Jacobson, D.L., Baltic, E., “Changing Optical 

Axis due to Reactor Operation,” Nucl. Instrum. 

Methods Phys. Res., Sect. A 651, 73 (2011). 

Hyland, L.L., Taraban, M.B., Hammouda, B., Yu, Y.B., 

“Mutually Reinforced Multicomponent Polysaccharide 

Networks,” Biopolymers 95(12), 840 (2011). 

Hyland, L.L., Taraban, M.B., Feng, Y., Hammouda, B., Yu, 

Y.B., “Viscoelastic Properties and Nanoscale Structures 

of Composite Oligopeptide-Polysaccharide Hydrogels,” 

Biopolymers 97(3), 177 (2012). [CHRNS] 

Iadicola, M., Gnäupel-Herold, T.H., “Effective X-ray Elastic 

Constant Measurement for In situ Stress Measurement 

of Biaxially Strained AA5754-O,” Mater. Sci. Eng., 

A 545, 168 (2012). 

Iida, K., Lee, S.-H., Cheong, S.-W., “Coexisting Order 

and Disorder Hidden in a Quasi-Two-Dimensional 

Frustrated Magnet,” Phys. Rev. Lett. 108(21), 217207 

(2012). [CHRNS] 

Iida, K., Qiu, Y., Sato, T.J., “Dzyaloshinsky-Moriya 

Interaction and Long Lifetime of the Spin State in 

the Cu3 Triangular Spin Cluster by Inelastic Neutron 

Scattering Measurements,” Phys. Rev. B 84(9), 094449 

(2011). [CHRNS] 

Iwata-Harms, J.M., Wong, F.J., Alaan, U.S., Kirby, B.J., 

Borchers, J.A., Toney, M.F., Nelson-Cheeseman, B.B., 

Liberati, M., Arenholz, E., Suzuki, Y., “Controlling 

Spin Ordering in Frustrated Magnets via Thin Film 

Heteroepitaxy,” Phys. Rev. B 85(21), 214424-1 (2012). 

Jacobson, D.L., Hussey, D.S., Baltic, E., “In Situ Imaging at 

the NIST Neutron Imaging Facility,” Mater. Res. Soc. 

Symp. Proc. 1318, 3 (2011). 

Jang, Y., Akgun, B., Kim, H., Satija, S., Char, K., 

“Controlled Release from Model Blend Multilayer 

Films Containing Mixtures of Strong and Weak 

Polyelectrolytes,” Macromolecules 45, 3542 (2012). 

Jendrzejewska, I., Zajdel, P., Goryczka, T., Goraus, J., Kita, 

A., Mydlarz, T., “Influence of Covalency and Anion 

Polarization on Magnetic and Electronic Properties of 

ZnCr2-xNixSe4,” J. Alloys Compd. 520, 153 (2012). 

Ju, H., Heuser, B.J., Abernathy, D.L., Udovic, T.J., 

“Comparison of FANS and ARCS Incoherent Inelastic 

Neutron Scattering Measurements of Hydrogen 

Trapped at Dislocations in Deformed Pd,” Nucl. 

Instrum. Methods Phys. Res., Sect. A 654, 522 (2011). 

Kamitakahara, W.A., Faraone, A., Liu, K.-H., Mou, C.-Y., 

“Temperature Dependence of Structure and Density 

for D2O Confined in MCM-41-S,” J. Phys.: Condens. 

Matter 24, 064106 (2012). 

Kang, X., Wu, H., Luo, J., Zhou, W., Wang, P., “A Simple 

and Efficient Approach to Synthesize Amidoborane 

Ammoniates: Case Study for Mg(NH2BH3)2(NH3)3 

with Unusual Coordination Structure,” J. Mater. 

Chem. 22, 13174 (2012). 

Karhu, E.A., Kahwaji, S., Robertson, M.D., Fritzsche, H., 

Kirby, B.J., Majkrzak, C.F., Monchesky, T.L., “Helical 

Magnetic Order in MnSi Thin Films,” Phys. Rev. B: 

Condens. Matter 84(6), 060404-1 (2011). 

Karhu, E.A., Rößler, U., Bogdanov, A.N., Kahwaji, S., 

Kirby, B.J., Fritzsche, H., Robertson, M.D., Majkrzak, 

C.F., Monchesky, T.L., “Chiral Modulations and 

Reorientation Effects in MnSi Thin Films,” Phys. Rev. 

B 85(9), 094429-1 (2012). 

Katayama, N., Matsubayashi, K., Nomura, Y., Ji, S., Leao, 

J., Green, M.A., Sato, T.J., Uwatoko, Y., Fujita, M., 

Yamada, K., Arita, R., Lee, S.-H., “Conductivity 

and Incommensurate Antiferromagnetism of 

Fe1.02Se0.10Te0.90 Under Pressure,” Europhys. Lett. 98, 

37002 (2012). 

72 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
Kauffman, K.L., Culp, J.T., Allen, A.J., Espinal, L., WongNg, W., Brown, T.D., Goodman, A., Bernardo, M.P., 

Pancoast, R.J., Chirdon, D., Matranga, C., “Selective 

Adsorption of CO2 from Light Gas Mixtures by Using 

a Structurally Dynamic Porous Coordination Polymer,” 

Angew. Chem. Int. Ed. 50, 10888 (2011). [CHRNS] 

Khatami, E., Helton, J.S., Rigol, M., “Numerical Study of 

the Thermodynamics of Clinoatacamite,” Phys. Rev. B 

85(6), 064401 (2012). 

Kim, F.S., Penumadu, D., Hussey, D.S., “Water Distribution 

Variation in Partially Saturated Granular Materials 

Using Neutron Imaging,” J. Geotech. Geoenviron. Eng. 

138(2), 147 (2012). 

Kim, J.-H., van der Vegte, M.A., Scaramucci, A., Artyukhin, 

S., Chung, J.-H., Park, S., Cheong, S.-W., Mostovoy, 

M., Lee, S.-H., “Magnetic Excitations in the LowTemperature Ferroelectric Phase of Multiferroic 

YMn2O5 Using Inelastic Neutron Scattering,” Phys. 

Rev. Lett. 107(9), 097401 (2011). [CHRNS] 

Kim, M.-H., Doh, J.-M., Han, S.C., Chae, K.H., Yu, B.-Y., 

Hong, K.T., Jackson, A., Anovitz, L.M., “The Pore Wall 

Structure of Porous Semi-Crystalline Anatase TiO2,” J. 

Appl. Crystallogr. 44(6), 1238 (2011). 

Kim, S.Y., Schweizer, K.S., Zukoski, C.F., “Multiscale 

Structure, Interfacial Cohesion, Adsorbed Layers, and 

Thermodynamics in Dense Polymer-Nanoparticle 

Mixtures,” Phys. Rev. Lett. 107(22), 225504-1 (2011). 

Kim, S.Y., Zukoski, C.F., “Role of Polymer Segment-Particle 

Surface Interactions in Controlling Nanoparticle 

Dispersions in Concentrated Polymer Solutions,” 

Langmuir 27, 10455 (2011). 

Kim, S.Y., Meyer, H.W., Saalwächter, K., Zukoski, C.F., 

“Polymer Dynamics in PEG-Silica Nanocomposites: 

Effects of Polymer Molecular Weight, Temperature and 

Solvent Dilution,” Macromolecules 45, 4225 (2012). 

Kim, S.W., Kim, S.-H., Halasyamani, P.S., Green, 

M.A., Bhatti, K.P., Leighton, C., Das, H., Fennie, 

C.J., “RbFe2+Fe3+F6: Synthesis, Structure, and 

Characterization of a New Charge-Ordered 

Magnetically Frustrated Pyrochlore-Related MixedMetal Fluoride,” Chem. Sci. 3, 741 (2012). 

Kim, Y.-J., Sorini, A.P., Stock, C., Perring, T.G., van den 

Brink, J., Devereaux, T.P., “Probing High-Energy 

Electronic Excitations in NiO Using Inelastic Neutron 

Scattering,” Phys. Rev. B 84(8), 085132-1 (2011). 

Kintzel, Jr., E.J., Kidder, M.K., Buchanan, III, A.C., Britt, 

P.F., Mamontov, E., Zamponi, M., Herwig, K.W., 

“Dynamics of 1,3-Diphenylpropane Tethered to the 

Interior Pore Surfaces of MCM-41,” J. Phys. Chem. C 

116, 923 (2011). 

Kirby, B.J., Kienzle, P.A., Maranville, B.B., Berk, N.F., 

Krycka, J., Heinrich, F., Majkrzak, C.F., “PhaseSensitive Specular Neutron Reflectometry for Imaging 

the Nanometer Scale Composition Depth Profile of 

Thin-Film Materials,” Curr. Opin. Colloid Interface 

Sci. 17, 44 (2012). 

Kirschner, S.B., Smith, N.P., Wepasnick, K.A., Katz, H.E., 

Kirby, B.J., Borchers, J.A., Reich, D.H., “X-ray and 

Neutron Reflectivity and Electronic Properties of 

PCBM-poly(bromo)styrene Blends and Bilayers with 

Poly(3- hexylthiophene),” J. Mater. Chem. 22, 4364 

(2012). 

Klimczuk, T., Wang, C.H., Lawrence, J.M., Xu, Q., 

Durakiewicz, T., Ronning, F., Llobet, A., Trouw, F., 

Kurita, N., Tokiwa, Y., Lee, H.-O., Booth, C.H., 

Gardner, J.S., Bauer, E.D., Joyce, J.J., Zandbergen, 

H.W., Movshovich, R., Cava, R.J., Thompson, J.D., 

“Crystal Fields, Disorder, and Antiferromagnetic ShortRange Order in Yb0.24Sn0.76Ru,” Phys. Rev. B 84(7), 

075152 (2011). 

Klose, C., Khaire, T.S., Wang, Y., Pratt, Jr., W.P., Birge, N.O., 

McMorran, B.J., Ginley, T.P., Borchers, J.A., Kirby, 

B.J., Maranville, B.B., Unguris, J., “Optimization of 

Spin-Triplet Supercurrent in Ferromagnetic Josephson 

Junctions,” Phys. Rev. Lett. 108(12), 127002-1 (2012). 

Kofu, M., Someya, T., Tatsumi, S., Ueno, K., Ueki, T., 

Watanabe, M., Matsunaga, T., Shibayama, M., García 

Sakai, V., Tyagi, M., Yamamuro, O., “Microscopic 

Insights into Ion Gel Dynamics using Neutron 

Spectroscopy,” Soft Matter 8, 7888 (2012). [CHRNS] 

Koga, T., Gin, P., Yamaguchi, H., Endoh, M.K., Asada, M., 

Sendogdular, L., Kobayashi, M., Takahara, A., Akgun, 

B., Satija, S.K., Sumi, T., “Generality of Anomalous 

Expansion of Polymer Chains in Supercritical Fluids,” 

Polymer 52, 4331 (2011). 

Publications
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 73 
Publications
 

Krueger, S., Shin, J.-H., Raghunandan, S., Curtis, J.E., 

Kelman, Z., “Atomistic Ensemble Modeling and SmallAngle Neutron Scattering of Intrinsically Disordered 

Protein Complexes: Applied to Minichromosome 

Maintenance Protein,” Biophys. J. 101, 2999 (2011). 

[CHRNS] 

Krueger, S., Huie, J.L., Kuzmanovic, D.A., “Small 

Angle Scattering Analysis of Virus-like Particles for 

Biomedical Diagnostic Assays,” in “Neutron Scattering 

Methods and Studies,”edited by Lyons, M. J. (NOVA 

Science Publishers, Inc.), Chap. 2, 35 (2011). 

Krycka, K., Borchers, J., Ijiri, Y., Booth, R., Majetich, 

S., “Polarization-Analyzed Small-Angle Neutron 

Scattering. II. Mathematical Angular Analysis,” J. Appl. 

Crystallogr. 45, 554 (2012). [CHRNS] 

Krycka, K., Chen, W., Borchers, J., Maranville, B., Watson, 

S., “Polarization-Analyzed Small-Angle Neutron 

Scattering. I. Polarized Data Reduction using Pol-Corr,” 

J. Appl. Crystallogr. 45, 546 (2012). [CHRNS] 

Kučerka, N., Holland, B.W., Gray, C.G., Tomberli, B., 

Katsara, J., “Scattering Density Profile Model of 

POPG Bilayers as Determined by Molecular Dynamics 

Simulations and Small-Angle Neutron and X-ray 

Scattering Experiments,” J. Phys. Chem. B 116, 232 

(2011). [CHRNS] 

Kučerka, N., Nieh, M.-P., Katsaras, J., “Fluid Phase Lipid 

Areas and Bilayer Thickness of Commonly used 

Phosphatidylcholines as a Function of Temperature,” 

Biochim. Biophys. Acta 1808, 2761 (2011). [CHRNS] 

Kulkarni, M.M., Yager, K.G., Sharma, A., Karim, A., 

“Combinatorial Block Copolymer Ordering on Tunable 

Rough Substrates,” Macromolecules 45(10), 4303 

(2012). [CHRNS] 

Kumari, H., Kline, S.R., Atwood, J.L., “Investigation of 

Encapsulation of Insulin Biotemplate within Cmethylresorcin[4]arenes,” Chem. Commun. 48, 3599 

(2012). 

Kumari, H., Mossine, A.V., Kline, S.R., Dennis, C.L., 

Fowler, D.A., Teat, S.J., Barnes, C.L., Deakyne, C.A., 

Atwood, J.L., “Controlling the Self-Assembly of MetalSeamed Organic Nanocapsules,” Angew. Chem. Int. 

Ed. 51, 1452 (2012). 

Kumari, H., Kline, S.R., Wycoff, W.G., Paul, R.L., Mossine, 

A.V., Deakyne, C.A., Atwood, J.L., “Solution-Phase 

Structures of Gallium-Containing Pyrogallol[4]arene 

Scaffolds,” Angew. Chem. Int. Ed. 51, 5086 (2012). 

Kumari, H., Kline, S.R., Schuster, N.J., Barnes, C.L., 

Atwood, J.L., “Exploring the Ellipsoidal and Core-Shell 

Geometries of Copper-Seamed C-alkylpyrogallol[4] 

arene Nanocapsules in Solution,” J. Am. Chem. Soc. 

133, 18102 (2011). 

Kumari, H., Kline, S.R., Schuster, N.J., Atwood, 

J.L., “Solution Structure of Copper-seamed Calkylpyrogallol[4]arene Nanocapsules with Varying 

Chain Lengths,” Chem. Commun. 47, 12298 (2011). 

[CHRNS] 

Kumi, B.C., Greer, S.C., “Micelles of Polybutadieneb-poly(ethylene oxide) in Deuterated Methanol and 

Deuterated Cyclohexane,” J. Colloid Interface Sci., in 

press. [CHRNS] 

Larson-Smith, K., Jackson, A., Pozzo, D.C., “SANS and 

SAXS Analysis of Charged Nanoparticle Adsorption at 

Oil-Water Interfaces,” Langmuir 28(5), 2493 (2012). 

[CHRNS] 

Lauw, Y., Horne, M.D., Rodopoulos, T., Lockett, V., Akgun, 

B., Hamilton, W.A., Nelson, A.R.J., “Structure of 

[C4mpyr][NTf2] Room-Temperature Ionic Liquid 

at Electrified Gold Interfaces,” Langmuir 28, 7374 

(2012). 

Lee, H., Kim, D.H., Witte, K.N., Ohn, K., Choi, J., Akgun, 

B., Satija, S.K., Won, Y.-Y., “Water is a Poor Solvent 

for Densely Grafted Poly(ethylene oxide) Chains: 

A Conclusion Drawn from a Self-Consistent Field 

Theory- Based Analysis of Neutron Reflectivity and 

Surface Pressure-Area Isotherm Data,” J. Phys. Chem. B 

116, 7367 (2012). 

Lee, W., Kofinas, P., Briber, R.M., “Structure Investigation 

of Poly((2-dimethylamino)ethyl Methacrylate)/Sodium 

Dodecylsulfate Complexes in Concentrated Poly((2- 

dimethylamino)ethyl Methacrylate) Solutions using 

Small Angle Neutron Scattering,” Polymer 53, 2942 

(2012). 

Levasseur, B., Ebrahim, A.M., Burress, J., Bandosz, T.J., 

“Interactions of NO2 at Ambient Temperature with 

Cerium-Zirconium Mixed Oxides Supported on SBA15,” J. Hazard. Mater. 197, 294 (2011). 

74 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
 

Li, H., Chiang, W.-S., Fratini, E., Ridi, F., Bausi, F., Baglioni, 

P., Tyagi, M., Chen, S.-H., “Dynamic Crossover in 

Hydration Water of Curing Cement Paste: The Effect 

of Superplasticizer,” J. Phys.: Condens. Matter 24, 

064108 (2012). 

Li, W.-H., Wang, C.-W., Hsu, D., Lee, C.-H., Wu, C.-M., 

Chou, C.-C., Yang, H.-D., Zhao, Y., Chang, S., Lynn, 

J.W., Berger, H., “Interplay Between the Magnetic and 

Electric Degrees of Freedom in Multiferroic Co3TeO6,” 

Phys. Rev. B 85(9), 094431 (2012). 

Li, X., Wu, B., Liu, Y., Pynn, R., Shew, C.-Y., Smith, G.S., 

Herwig, K.W., Robertson, J.L., Chen, W.-R., Liu, L., 

“Contrast Variation in Spin-Echo Small Angle Neutron 

Scattering,” J. Phys.: Condens. Matter 24, 064115 

(2012). 

Lindstrom, R.M., “Hydrogen Measurement in Steel: A 

Query,” J. Radioanal. Nucl. Chem. 289(3), 289 (2011). 

Lindstrom, R.M., “A Second-Generation Low-Background 

Gamma Spectrometer,” Transactions of the American 

Nuclear Society 105, 349 (2011). 

Lindstrom, R.M., Fischbach, E., Buncher, J.B., Jenkins, 

J.H., Yue, A., “Absence of a Self-Induced Decay Effect 

in 198Au,” Nucl. Instrum. Methods Phys. Res., Sect. 

659, 269 (2011). 

Lioudyno, M.I., Broccio, M., Sokolov, Y., Rasool, S., Wu, 

J., Alkire, M.T., Liu, V., Kozak, J.A., Dennison, 

P.R., Glabe, C.G., Lösche, M., Hall, J.E., “Effect of 

Synthetic Aβ Peptide Oligomers and Fluorinated 

Solvents on Kv1.3 Channel Properties and Membrane 

Conductance,” PloS ONE 7(4), e35090 (2012). 

Liu, C.K., Warr, G.G., “Resiliently Spherical Micelles 

of Alkyltrimethylammonium Surfactants with 

Multivalent, Hydrolyzable Counterions,” Langmuir 28, 

11007 (2012). [CHRNS] 

Liu, J., Kirby, B.J., Gray, B., Kareev, M., Habermeier, H.­

U., Cristiani, G., Freeland, J.W., Chakhalian, J., 

“Interfacial Electronic and Magnetic Properties of a 

Y0.6Pr0.4Ba2Cu3O7/La2/3Ca1/3MnO3 Superlattice,” Phys. 

Rev. B 84(9), 092506 (2011). 

Liu, X., Smith, D.J., Fan, J., Zhang, Y.-H., Cao, H., Chen, 

Y.P., Leiner, J., Kirby, B.J., Dobrowolska, M., Furdyna, 

J.K., “Structural Properties of Bi2Te3 and Bi2Se3 

Topological Insulators Grown by Molecular Beam 

Epitaxy on GaAs(001) Substrates,” Appl. Phys. Lett. 

99(17), 171903 (2011). 

Liu, X., Smith, D.J., Fan, J., Zhang, Y.-H., Cao, H., 

Chen, Y.P., Kirby, B.J., Sun, N., Ruggiero, S.T., 

Leiner, J., Pimpinella, R.E., Hagmann, J., 

Tivakornsasithorn, K., Dobrowolska, M., Furdyna, 

J.K., “Topological Insulators Bi2Te3 and Bi2Se3 Grown 

by MBE on (001) GaAs Substrates,” AIP Cong. Proc. 

1416, 105 (2011). 

Liu, Y., Brown, C.M., Neumann, D.A., Geohegan, D.B., 

Puretzky, A.A., Rouleau, C.M., Hu, H., Styers-Barnett, 

D., Krasnov, P.O., Yakobson, B.I., “Metal-Assisted 

Hydrogen Storage on Pt-Decorated Single-Walled 

Carbon Nanohorns,” Carbon , in press. 

López-Barrón, C.R., Basavaraj, M.G., DeRita, L., Wagner, 

N.J., “Sponge-to-Lamellar Transition in a DoubleTail Cationic Surfactant/Protic Ionic Liquid System: 

Structural and Rheological Analysis,” J. Phys. Chem. B 

116, 813 (2012). 

López-Barrón, C.R., Porcar, L., Eberle, A.P.R., Wagner, 

N.J., “Dynamics of Melting and Recrystallization 

in a Polymeric Micellar Crystal Subjected to Large 

Amplitude Oscillatory Shear Flow,” Phys. Rev. Lett. 

108(25), 258301 (2012). 

Lu, H., Akgun, B., Russell, T.P., “Morphological 

Characterization of a Low-Bandgap Crystalline 

Polymer:PCBM Bulk Heterojunction Solar Cells,” Adv. 

Energy Mater. 1, 870 (2011). 

Lu, H., Akgun, B., Wei, X., Li, L., Satija, S.K., Russell, 

T.P., “Temperature-Triggered Micellization of Block 

Copolymers on an Ionic Liquid Surface,” Langmuir 27, 

12443 (2011). 

Lu, Y., Kwan, A.H., Trewhella, J., Jeffries, C.M., “The C0C1 

Fragment of Human Cardiac Myosin Binding Protein 

C Has Common Binding Determinants for Both Actin 

and Myosin,” J. Mol. Biol. 413, 908 (2011). 

Publications
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 75 
Publications
 

Luo, H., Zhang, R., Laver, M., Yamani, Z., Wang, M., Lu, 

X., Wang, M., Chen, Y., Li, S., Chang, S., Lynn, J.W., 

Dai, P., “Coexistence and Competition of the ShortRange Incommensurate Antiferromagnetic Order with 

Superconducting in BaFe2-xNixAs2,” Phys. Rev. Lett. 

108(24), 247002 (2012). 

Luo, J., Wu, H., Zhou, W., Kang, X., Fang, Z., Wang, P., 

“LiBH4• NH3BH3: A New Lithium Borohydride 

Ammonia Borane Compound with a Novel Structure 

and Favorable Hydrogen Storage Properties,” Int. J. 

Hydrogen Energy 37, 10750 (2012). 

Lynn, J.W., Chen, Y., Chang, S., Zhao, Y., Chi, S., Ratcliff, 

II, W., Ueland, B.G., Erwin, R.W., “Double-Focusing 

Thermal Triple-Axis Spectrometer at the NCNR,” The 

Journal of Research of NIST 117, 61 (2012). 

Maiti, T., Guo, R., Bhalla, A.S., “Evaluation of Experimental 

Resume of BaZrxTi1-xO3 with Perspective to Ferroelectric 

Relaxor Family: An Overview,” Ferroelectrics 425, 

4 (2011). 

Maitland, C.F., Buckley, C.E., O’Connor, B.H., Butler, 

P.D., Hart, R.D., “Characterization of the Pore 

Structure of Metakaolin-derived Geopolymers by 

Neutron Scattering and Electron Microscopy,” J. Appl. 

Crystallogr. 44(4), 697 (2011). [CHRNS] 

Majkrzak, C.F., Carpenter, E., Heinrich, F., Berk, N.F., 

“When Beauty is Only Skin Deep; Optimizing the 

Sensitivity of Specular Neutron Reflectivity for Probing 

Structure Beneath the Surface of Thin Films,” J. Appl. 

Phys. 110(10), 102212 (2011). 

Malherbe, J., Isaure, M.-P., Séby, F., Watson, R.P., Rodriguez 

-Gonzalez, P., Stutzman, P.E., Davis, C.W., Maurizio, 

C., Unceta, N., Sieber, J.R., Long, S.E., Donard, 

O.F.X., “Evaluation of Hexavalent Chromium 

Extraction Method EPA Method 3060A for Soils using 

XANES Spectroscopy,” Environ. Sci. Technol. 45, 

10492 (2011). 

Malingowski, A.C., Stephens, P.W., Huq, A., Huang, Q., 

Khalid, S., Khalifah, P.G., “Substitutional Mechanism 

of Ni into the Wide-Band-Gap Semiconductor 

InTaO4

 and its Implications for Water Splitting Activity 

in the Wolframite Structure Type,” Inorg. Chem. 51, 

6096 (2012). 

Mallia, V.A., Terech, P., Weiss, R.G., “Correlations of 

Properties and Structures at Different Length Scales 

of Hydro- and Organo-gels Based on N-Alkyl-(R)-12-

Hydroxyoctadecylammonium Chlorides,” J. Phys. 

Chem. B 115, 12401 (2011). 

Mang, J.T., Hjelm, R.P., “Small-Angle Neutron Scattering 

and Contrast Variation Measurement of the Interfacial 

Surface Area in PBX 9501 as a Function of Pressing 

Intensity,” Propellants Explos. Pyrotech. 36(5), 439 

(2011). [CHRNS] 

Maranas, J.K., “Solid Polymer Electrolytes”, in “Dynamics 

of Soft Matter Neutron Applications and Techniques,” 

edited by Sakai, V., Chen, S.-H., Alba-Simionesco, 

C.(Springer Science & Business Media, LLC, New 

York, NY) Chap, 5, 123 (2012). [CHRNS] 

Mastalerz, M., He, L., Melnichenko, Y.B., Rupp, J.A., 

“Porosity of Coal and Shale: Insights from Gas 

Adsorption and SANS/USANS Techniques,” Energy 

Fuels, in press. [CHRNS] 

Melnichenko, Y.B., He, L., Sakurovs, R., Kholodenko, 

A.L., Blach, T., Mastalerz, M., Radliński, A.P., Cheng, 

G., Mildner, D.F.R., “Accessibility of Pores in Coal 

to Methane and Carbon Dioxide,” Fuel 91(1), 200 

(2012). [CHRNS] 

Mildner, D.F.R., Barker, J. G., Kline, S.R., “The Effect of 

Gravity on the Resolution of Small-Angle Neutron 

Diffraction Peaks,” J. Appl. Crystallogr. 44(5), 1127 

(2011). 

Mildner, D.F.R., “Modeling the Transmission of Curved 

Neutron Guides with Non-Perfect Reflectivity,” Nucl. 

Instrum. Methods Phys. Res., Sect. A 656, 96 (2011). 

Mildner, D.F.R., Cubitt, R., “The Effect of Gravity on 

the Debye-Scherrer Ring in Small-Angle Neutron 

Scattering,” J. Appl. Crystallogr. 45(1), 124 (2012). 

Mishler, J., Wang, Y., Mukherjee, P.P., Mukundan, R., Borup, 

R.L., “Subfreezing Operation of Polymer Electrolyte 

Fuel Cells: Ice Formation and Cell Performance Loss,” 

Electrochim. Acta 65, 127 (2012). 

Mishler, J., Wang, Y., Mukundan, R., Spendelow, J., Hussey, 

D.S., Jacobson, D.L., Borup, R.L., “Probing the 

Water Content in Polymer Electrolyte Fuel Cells using 

Neutron Radiography,” Electrochim. Acta 75, 1 (2012). 

76 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
Mossine, A.V., Kumari, H., Fowler, D.A., Maerz, A.K., 

Kline, S.R., Barnes, C.L., Atwood, J.L., “Ferrocene as 

a Hydrophobic Templating Agent with Pyrogallol[4] 

arenes,” Isr. J. Chem. 51, 840 (2011). 

Mossine, A.V., Kumari, H., Fowler, D.A., Shih, A., Kline, 

S.R., Barnes, C.L., Atwood, J.L., “Ferrocene Species 

Included within a Pyrogallol[4]arene Tube,” Eur. J. 

Org. Chem., in press. 

Mumm, H.P., Chupp, T.E., Coulter, K.P., Cooper, R.L., 

Freedman, S.J., Fujikawa, B.K., García, A., Jones, 

G.L., Nico, J.S., Thompson, A.K., Trull, C.A., 

Wietfeldt, F.E., Wilkerson, J.F., “A New Limit on 

Time-Reversal-Invariance Violation in Beta Decay: 

Results of the emiT-II Experiment,” in “Proceedings of 

Science,” edited by unknown, (The 2011 Europhysics 

Conf. on High Energy Physics, July 2011, Grenoble, 

France) 1 (2011). 

Mumm, H.P., Chupp, T.E., Cooper, R.L., Coulter, K.P., 

Freedman, S.J., Fujikawa, B.K., García, A., Jones, G.L., 

Nico, J.S., Thompson, A.K., Trull, C.A., Wilkerson, 

J.F., Wietfeldt, F.E., “New Limit on Time-Reversal 

Violation in Beta Decay,” Phys. Rev. Lett. 107(10), 

102301 (2011). 

Nagao, M., “Temperature and Scattering Contrast 

Dependencies of Thickness Fluctuations in Surfactant 

Membranes,” J. Chem. Phys. 135(7), 074704 (2011). 

[CHRNS] 

Nagpure, S.C., Downing, R.G., Bhushan, B., Babu, S.S., 

“Discovery of Lithium in Copper Current Collectors 

used in Batteries,” Scripta Mater., in press. 

Nakatsuji, S., Kuga, K., Kimura, K., Satake, R., Katayama, 

N., Nishibori, E, Sawa, H., Ishii, R., Hagiwara, 

M., Bridges, F., Ito, T.U., Higemoto, W., Karaki, Y., 

Halim, M., Nugroho, A.A., Rodriguez-Rivera, J.A., 

Green, M.A., Broholm, C., “Spin-Orbital Short 

Range-Order on a Honeycomb-Based Lattice,” Science 

336, 559 (2012). 

Newbloom, G.M., Weigandt, K.M., Pozzo, D.C., “Electrical, 

Mechanical, and Structural Characterization of 

Self- Assembly in Poly(3-hexylthiophene) Organogel 

Networks,” Macromolecules 45(8), 3452 (2012). 

[CHRNS] 

Nickels, J.D., Curtis, J.E., O’Neill, H., Sokolov, A.P., 

“Role of Methyl Groups in Dynamics and Evolution 

of Biomolecules,” J. Biol. Phys. 38(3), 497 (2012). 

[CHRNS] 

Nieh, M.-P., Dolinar, P., Kučerka, N., Kline, S.R., DebeerSchmitt, L.M., Littrell, K.C., Katsaras, J., “Formation 

of Kinetically Trapped Nanoscopic Unilamellar Vesicles 

from Metastable Nanodiscs,” Langmuir 27, 14308 

(2011). [CHRNS] 

O’Malley, M.A., Helgeson, M.E., Wagner, N.J., Robinson, 

A.S., “Toward Rational Design of Protein Detergent 

Complexes: Determinants of Mixed Micelles That Are 

Critical for the In Vitro Stabilization of a G-Protein 

Coupled Receptor,” Biophys. J. 101, 1938 (2011). 

Oleson, T.A., Sahai, N., Wesolowski, D.J., Dura, J.A., 

Majkrzak, C.F., Giuffre, A.J., “Neutron Reflectivity 

Study of Substrate Surface Chemistry Effects on 

Supported Phospholipid Bilayer Formation on (1120) 

Sapphire,” J. Colloid Interface Sci. 370, 192 (2012). 

Owejan, J.E., Owejan, J.P., DeCaluwe, S.C., Dura, J.A., 

“Solid Electrolyte Interphase in Li-Ion Batteries: 

Evolving Structures Measured in situ by Neutron 

Reflectometry,” Chem. Mater. 24, 2133 (2012). 

Owejan, J.P., Gagliardo, J.J., Harris, S.J., Wang, H., Hussey, 

D.S., Jacobson, D.L., “Direct Measurement of Lithium 

Transport in Graphite Electrodes using Neutrons,” 

Electrochim. Acta. 66, 94 (2012). 

Pai, S.S., Heinrich, F., Canady, A.L., Przybycien, T.M., 

Tilton, R.D., “Coverage-Dependent Morphology of 

PEGylated Lysozyme Layers Adsorbed on Silica,” J. 

Colloid Interface Sci. 370, 170 (2012). 

Pai, S.S., Hammouda, B., Hong, K., Pozzo, D.C., 

Przybycien, T.M., Tilton, R.D., “The Conformation 

of Poly(ethylene glycol) Chain in Mono-PEGylated 

Lysozyme and Mono- PEGylated Human Growth 

Hormone,” Bioconjugate Chem. 22, 2317 (2011). 

[CHRNS] 

Pajerowski, D.M., Hallock, S.J., “Demagnetization in 

Photomagnetic Films,” J. Magn. Magn. Mater. 324, 

1818 (2012). 

Publications
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 77 
Publications
 

Pajerowski, D.M., Yamamoto, T., Einaga, Y., 

“Photomagnetic K0.25Ni1-xCox[Fe(CN)6]•nH2O and 

K0.25Co[Fe(CN)6]0.75(1-y)•nH2O Prussian Blue Analogue 

Solid Solutions,” Inorg. Chem. 51, 3648 (2012). 

Pan, J., Heberle, F.A., Tristram-Nagle, S., Szymanski, M., 

Koepfinger, M., Katsaras, J., Kučerka, N., “Molecular 

Structures of Fluid Phase Phosphatidylglycerol Bilayers 

as Determined by Small Angle Neutron and X-ray 

Scattering,” Biochim. Biophys. Acta, in press. 

Peng, H.-G., Tyagi, M., Page, K. A., Soles, C. L., “Inelastic 

Neutron Scattering on Polymer Electrolytes for 

Lithium-Ion Batteries,” in “Polymers for Energy Storage 

and Delivery: Polyelectrolytes for Batteries and Fuel 

Cells, Volume 1096,” edited by Page, K. A., Soles, C. 

L., Runt, J. (ACS Publications, Washington, D.C.), 

Chap. 5, 67 (2012). [CHRNS] 

Peri, S.R., Akgun, B., Satija, S.K., Jiang, H., Enlow, J., 

Bunning, T.J., Foster, M.D., “Control of Interface 

Nanoscale Structure Created by Plasma-Enhanced 

Chemical Vapor Deposition,” ACS Appl. Mater. 

Interfaces 3, 3375 (2011). 

Perry, N.H., Mason, T.O., Ma, C., Navrotsky, A., Shi, Y., 

Bettinger, J.S., Toney, M.F., Paudel, T.R., Lany, S., 

Zunger, A., “Co3O4-Co2ZnO4 Spinels: The Case for a 

Solid Solution,” J. Solid State Chem. 190, 143 (2012). 

Pfefferkorn, C.M., Heinrich, F., Sodt, A.J., Maltsev, A.S., 

Pastor, R.W., Lee, J.C., “Depth of α-Synuclein in 

a Bilayer Determined by Fluorescence, Neutron 

Reflectometry, and Computation,” Biophys. J. 102, 

613 (2012). 

Porcar, L., Pozzo, D., Langenbucher, G., Moyer, J., Butler, 

P.D., “Rheo-Small-Angle Neutron Scattering at the 

National Institute of Standards and Technology Center 

for Neutron Research,” Rev. Sci. Instrum. 82(8), 

083902 (2011). 

Prabhu, V.M., Kang, S., Sha, J., Bonnesen, P.V., Satija, 

S., Wu, W.L., Ober, C.K., “Neutron Reflectivity 

Characterization of the Photoacid Reaction-Diffusion 

Latent and Developed Images of Molecular Resists 

for Extreme Ultraviolet Lithography,” Langmuir 28, 

7665 (2012). 

Prabhu, V.M., Kang, S., Kline, R.J., DeLongchamp, D.M., 

Fischer, D.A., Wu, W-L., Satija, S.K., Bonnesen, P.V., 

Sha, J., Ober, C.K., “Characterization of the Nonuniform Reaction in Chemically Amplified Calix[4] 

Resorcinarene Molecular Resist Thin Films,” Aust. J. 

Chem. 64(8), 1065 (2011). 

Prabhu, V.M., Reipa, V., “In situ Electrochemical SmallAngle Neutron Scattering (eSANS) for Quantitative 

Structure and Redox Properties of Nanoparticles,” J. 

Phys. Chem. Lett. 3, 646 (2012). [CHRNS] 

Pushin, D.A., Huber, M.G., Arif, M., Cory, D.G., 

“Experimental Realization of Decoherence-Free 

Subspace in Neutron Interferometry,” Phys. Rev. Lett. 

107(15), 150401 (2011). 

Qian, B., Lee, J., Hu, J., Wang, G.C., Kumar, P., Fang, M.H., 

Liu, T.J., Fobes, D., Pham, H., Spinu, L., Wu, X.S., 

Green, M., Lee, S.H., Mao, Z.Q., “Ferromagnetism in 

CuFeSb: Evidence of Competing Magnetic Interactions 

in Iron-Based Superconductors,” Phys. Rev. B 85(14), 

144427 (2012). 

Qian, K.K., Bogner, R.H., “Application of Mesoporous 

Silicon Dioxide and Silicate in Oral Amorphous Drug 

Delivery Systems,” J. Pharm. Sci. 101(2), 444 (2012). 

Qian, K.K., Wurster, D.E., Bogner, R.H., “Spontaneous 

Crystalline-to-Amorphous Phase Transformation of 

Organic or Medicinal Compounds in the Presence of 

Porous Media, Part 3: Effect of Moisture,” Pharm. Res., 

in press. 

Qian, K.K., Zhou, W., Xu, X., Udovic, T.J., 

“Characterization of Medicinal Compounds Confined 

in Porous Media by Neutron Vibrational Spectroscopy 

and First-Principles Calculations: A Case Study with 

Ibuprofen,” Pharm. Res., in press. 

Queen, W.L., Brown, C.M., Britt, D.K., Zajdel, P., Hudson, 

M.R., Yaghi, O.M., “Site-Specific CO2 Adsorption 

and Zero Thermal Expansion in an Anisotropic Pore 

Network,” J. Phys. Chem. C 115, 24915 (2011). 

Queen, W.L., Bloch, E.D., Brown, C.M., Hudson, M.R., 

Mason, J.A., Murray, L.J., Ramirez-Cuesta, A.J., 

Peterson, V.K., Long, J.R., “Hydrogen Adsorption in 

the Metal-Organic Frameworks Fe2(dobdc) and Fe2(O2) 

(dobdc),” Dalton Trans. 41, 4180 (2012). 

78 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
Ramachandran, R., Beaucage, G., Rai, D.K., Lohse, D.J., 

Sun, T., Tsou, A.H., Norman, A., Hadjichristidis, N., 

“Quantification of Branching in Model Three-Arm Star 

Polyethylene,” Macromolecules 45(2), 1056 (2012). 

Ramazanoglu, M., Ratcliff, II, W., Yi, H.T., Sirenko, A.A., 

Cheong, S.-W., Kiryukhin, V., “Giant Effect of 

Uniaxial Pressure on Magnetic Domain Populations in 

Multiferroic Bismuth Ferrite,” Phys. Rev. Lett. 107(6), 

067203 (2011). 

Ramazanoglu, M., Laver, M., Ratcliff, II, W., Watson, 

S.M., Chen, W.C., Jackson, A., Kothapalli, K., Lee, 

S., Cheong, S.-W., Kiryukhin, V., “Local Weak 

Ferromagnetism in Single-Crystalline Ferroelectric 

BiFeO3,” Phys. Rev. Lett. 107(20), 207206 (2011). 

Reyenga, Jr., G.J., “NCNR Control Room Modernization 

Phase I” in “Proc. of the American Nuclear Society,” 

edited by unknown, (American Nuclear Society 2011 

Winter Meeting, Washington, D.C., October 2011), 

in press. 

Richards, J.J., Weigandt, K.M., Pozzo, D.C., “Aqueous 

Dispersions of Colloidal Poly(3-hexylthiophene) 

Gel Particles with High Internal Porosity,” J. Colloid 

Interface Sci. 364, 341 (2011). [CHRNS] 

Rikkou-Kalourkoti, M., Loizou, E., Porcar, L., 

Matyjaszewski, K., Patrickios, C.S., “End-linked, 

Amphiphilic, Degradable Polymer Conetworks: 

Synthesis by Sequential Atom Transfer Radical 

Polymerization using a Bifunctional, Cleavable 

Initiator,” Polym. Chem. 3, 105 (2012). 

Ripley, E.M., Li, C., Moore, C.H., Elswick, E.R., Maynard, 

J.B., Paul, R.L., Sylvester, P., Seo, J.H., Shimizu, N., 

“Analytical Methods for Sulfur Determination in 

Glasses, Rocks, Minerals and Fluid Inclusions,” in 

“Reviews in Mineralogy and Geochemistry, Volume 

73,” edited by Behrens, H., Webster, J.D.(The 

Mineralogical Society of America, Chantilly, VA), 

Chap. 2, 9 (2011). 

Ro, H.W., Akgun, B., O’Connor, B.T., Hammond, M., 

Kline, R.J., Snyder, C.R., Satija, S.K., Ayzner, A.L., 

Toney, M.F., Soles, C.L., DeLongchamp, D.M., 

“Poly(3-hexylthiophene) and [6,6]-Phenyl-C61-Butyric 

Acid Methyl Ester Mixing in Organic Solar Cells,” 

Macromolecules, in press. 

Rodriguez, E.E., Stock, C., Zajdel, P., Krycka, K. 

L., Majkrzak, C.F., Zavalij, P., Green, M.A., 

“Magnetic- Crystallographic Phase Diagram of the 

Superconducting Parent Compound Fe1+xTe,” Phys. 

Rev. B 84(6), 064403 (2011). [CHRNS] 

Roh, J.H., Tyagi, M., Briber, R.M., Woodson, S.A., Sokolov, 

A.P., “The Dynamics of Unfolded Versus Folded tRNA: 

The Role of Electrostatic Interactions,” J. Am. Chem. 

Soc. 133, 16406 (2011). [CHRNS] 

Rosales, A.M., Murnen, H.K., Kline, S.R., Zuckermann, 

R.N., Segalman, R.A., “Determination of the 

Persistence Length of Helical and Non-Helical 

Polypeptoids in Solution,” Soft Matter 8, 3673 (2012). 

[CHRNS] 

Ross, K.A., Yaraskavitch, L.R., Laver, M., Gardner, J.S., 

Quilliam, J.A., Meng, S., Kycia, J.B., Singh, D.K., 

Proffen, Th., Dabkowska, H.A., Gaulin, B.D., 

“Dimensional Evolution of Spin Correlations in the 

Magnetic Pyrochlore Yb2Ti2O7,” Phys. Rev. B 84(17), 

174442 (2011). [CHRNS] 

Ross, K.A., Savary, L., Gaulin, B.D., Balents, L., “Quantum 

Excitations in Quantum Spin Ice,” Phys. Rev. X 1(2), 

021002 (2011). [CHRNS] 

Saam, B., Petukhov, A.K., Chastagnier, J., Gentile, T.R., 

Golub, R., Swank, C.M., “Comment on “Pressure 

Dependence of Wall Relaxation in Polarized 3

He 

Gaseous Cells”,” Phys. Rev. A. 85(4), 047401 (2012). 

Saha, S.R., Butch, N.P., Drye, T., Magill, J., Ziemak, S., 

Kirshenbaum, K., Zavalij, P.Y., Lynn, J.W., Paglione, 

J., “Structural Collapse and Superconductivity in RareEarth-Doped CaFe2As2,” Phys. Rev. B 85(2), 024525 

(2012). 

Şahin, İ., “Random Lines: A Novel Population Set-Based 

Evolutionary Global Optimization Algorithm.” in 

“Genetic Programming, Volume 6621,” edited by Silva, 

S., Foster, J.A., Nicolau, M., Machado, P., Giacobini, 

M, (Springer Berlin Heidelberg, Germany) 97 (2011). 

Sakurovs, R., He, L., Melnichenko, Y.B., Radlinski, A.P., 

Blach, T., Lemmel, H., Mildner, D.F.R., “Pore Size 

Distribution and Accessible Pore Size Distribution 

in Bituminous Coals,” International Journal of Coal 

Geology 100, 51 (2012). [CHRNS] 

Publications
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 79 
Publications
 

Sander, L.C., Bedner, M., Tims, M.C., Yen, J.H., Duewer, 

D.L., Porter, B., Christopher, S.J., Day, R.D., 

Long, S.E., Molloy, J.L., Murphy, K.E., Lang, B.E., 

Lieberman, R., Wood, L.J., Payne, M.J., Roman, 

M.C., Betz, J.M., NguyenPho, A., Sharpless, K.E., 

Wise, S.A., “Development and Certification of Green 

Tea-Containing Standard Reference Materials,” Anal. 

Bioanal. Chem. 402, 473 (2012). 

Santos, T.S., Kirby, B.J., Kumar, S., May, S.J., Borchers, 

J.A., Maranville, B.B., Zarestky, J., te Velthuis, 

S.G.E., van den Brink, J., Bhattacharya, A., “Delta 

Doping of Ferromagnetism in Antiferromagnetic 

Manganite Superlattices,” Phys. Rev. Lett. 107(16), 

167202 (2011). 

Sarte, P.M., Silverstein, H.J., Van Wyk, B.T.K., Gardner, 

J.S., Qiu, Y., Zhou, H.D., Wiebe, C.R., “Absence of 

Long -Range Magnetic Ordering in the Pyrochlore 

Compound Er2Sn2O7,” J. Phys.: Condens. Matter 23, 

382201 (2011). [CHRNS] 

Selvam, P., Bharatwaj, B., Porcar, L., da Rocha, S.R.P., 

“Reverse Aqueous Microemulsions in 

Hydrofluoroalkane Propellants and their Aerosol 

Characteristics,” Int. J. Pharm. 422, 428 (2012). 

Shekhar, P., Nanda, H., Lösche, M., Heinrich, F., 

“Continuous Distribution Model for the Investigation 

of Complex Molecular Architectures near Interfaces 

with Scattering Techniques,” J. Appl. Phys. 110(10), 

1022161 (2011). 

Shenoy, S., Shekhar, P., Heinrich, F., Daou, M.-C., Gericke, 

A., Ross, A.H., Lösche, M., “Membrane Association 

of the PTEN Tumor Suppressor: Molecular Details of 

the Protein-Membrane Complex from SPR Binding 

Studies and Neutron Reflection,” PloS ONE 7(4), 

e32591 (2012). 

Shew, C.-Y., Do, C., Hong, K., Liu, Y., Porcar, L., Smith, 

G.S., Chen, W.-R., “Conformational Effect on 

Small Angle Neutron Scattering Behavior of 

Interacting Polyelectrolyte Solutions: A Perspective 

of Integral Equation Theory,” J. Chem. Phys. 137(2), 

024907 (2012). 

Shi, X., Yang, J., Salvador, J.R., Chi, M., Cho, J.Y., Wang, 

H., Bai, S., Yang, J., Zhang, W., Chen, L., “MultipleFilled Skutterudites: High Thermoelectric Figure of 

Merit through Separately Optimizing Electrical and 

Thermal Transports,” J. Am. Chem. Soc. 134, 2842 

(2012). [CHRNS] 

Siderius, D.W., Krekelberg, W.P., Roberts, C.J., Shen, 

V.K., “Osmotic Virial Coefficients for Model Protein 

and Colloidal Solutions: Importance of Ensemble 

Constraints in the Analysis of Light Scattering Data,” J. 

Chem. Phys. 136(17), 175102 (2012). 

Siegel, J.B., Lin, X., Stefanopoulou, A., “On the Accuracy 

and Simplifications of Battery Models using In 

Situ Measurements of Lithium Concentration in 

Operational Cells,” in “2012 American Control 

Conference” edited by unknown, (Fairmont Queen 

Elizabeth, Montreal, QC, Canada June 2012), 1362 

(2012). 

Siegel, J.B., Lin, X., Stefanopoulou, A.G., Hussey, D.S., 

Jacobson, D.L., Gorisch, D., “Neutron Imaging of 

Lithium Concentration in LFP Pouch Cell Battery,” J. 

Electrochem. Soc. 158(5), A523 (2011). 

Simmons, J.M., Yildirim, T., Hamaed, A., Antonelli, 

D.M., Webb, M.I., Walsby, C.J., “Direct Observation 

of Activated Hydrogen Binding to a Supported 

Organometallic Compound at Room Temperature,” 

Chem. Eur. J. 18, 4170 (2012). 

Simonson, J.W., Yin, Z.P., Pezzoli, M., Guo, J., Liu, J., Post, 

K., Efimenko, A., Hollmann, N., Hu, Z., Lin, H.-J., 

Chen, C.-T., Marques, C., Leyva, V., Smith, G., Lynn, 

J.W., Sun, L.L., Kotliar, G., Basov, D.N., Tjeng, L.-H., 

Aronson, M.C., “From Antiferromagnetic Insulator to 

Correlated Metal in Pressurized and Doped LaMnPo,” 

PNAS 109(27), 10751 (2012). 

Singh, D.K., Thamizhavel, A., Lynn, J.W., Dhar, S., 

Rodriguez-Rivera, J., Herman, T., “Field-induced 

Quantum Fluctuations in the Heavy Fermion 

Superconductor CeCu2Ge2,” Scientific Reports 1(117), 

1 (2011). [CHRNS] 

Singh, D.K., Thamizhavel, A., Chang, S., Lynn, J.W., 

Joshi, D.A., Dhar, S.K., Chi, S., “Coupling of FieldInduced Spin Fluctuations and Spin-Density Wave in 

Intermetallic CeAg2Ge2,” Phys. Rev. B 84(5), 052401 

(2011). [CHRNS] 

80 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
Sinha, K., Wang, W., Winey, K.I., Maranas, J.K., “Dynamic 

Patterning in PEO-Based Single Ion Conductors for 

Li Ion Batteries,” Macromolecules 45, 4354 (2012). 

[CHRNS] 

Skripov, A.V., Mushnikov, N.V., Terent’ev, P.B., Gaviko, 

V.S., Udovic, T.J., Rush, J.J., “Hydrogen Dynamics 

in Ce2Fe17H5: Inelastic and Quasielastic Neutron 

Scattering Studies,” J. Phys.: Condens. Matter 23, 

405402 (2011). [CHRNS] 

Sobkowicz, M.J., Jones, R.L., Kline, R.J., DeLongchamp, 

D.M., “Effect of Fullerenes on CrystallizationInduced Aggregation in Polymer Photovoltaics 

Casting Solutions,” Macromolecules 45, 1046 (2011). 

[CHRNS] 

Song, X., Sun, Z., Huang, Q., Rettenmayr, M., Liu, X., 

Seyring, M., Li, G., Rao, G., Yin, F., “Adjustable Zero 

Thermal Expansion in Antiperovskite Manganese 

Nitride,” Adv. Mater. 23, 4690 (2011). 

Sora, I.N., Caronna, T., Fontana, F., de Julián Fernández, 

C., Caneschi, Green, M., “Crystal Structures and 

Magnetic Properties of Strontium and Copper 

Doped Lanthanum Ferrites,” J. Solid State Chem. 

191, 33 (2012). 

Srinivas, G., Ford, J., Zhou, W., Yildirim, T., “Zn-MOF 

Assisted Dehydrogenation of Ammonia Borane: 

Enhanced Kinetics and Clean Hydrogen Generation,” 

Int. J. Hydrogen Energy 37, 3633 (2012). 

Srinivas, G., Burress, J., Yildirim, T., “Graphene Oxide 

Derived Carbons (GODCs): Synthesis and Gas 

Adsorption Properties,” Energy Environ. Sci. 5(4), 

6453 (2012). 

Stein, D.M., Grinberg, I., Rappe, A.M., Davies, P.K., 

“Multiple Dielectric Transitions in the PbTiO3 ­

Bi(Zn1/2Ti2)O3-Bi(Mg1/2Ti1/2)O3 System,” J. Appl. 

Phys. 110(7), 074110 (2011). 

Stewart, J.R., Ehlers, G., Wills, A.S., Bramwell, S.T., 

Gardner, J.S., “Comment on “Magnetic Structure of 

Gd2Ti2O7,” Phys. Rev. B 85(10), 106401 (2012). 

Stock, C., Sokolov, D.A., Bourges, P., Tobash, P.H., Gofryk, 

K., Ronning, F., Bauer, E.D., Rule, K.C., Huxley, A.D., 

“Anisotropic Critical Magnetic Fluctuations in the 

Ferromagnetic Superconductor UCoGe,” Phys. Rev. 

Lett. 107(18), 187202 (2011). [CHRNS] 

Stock, C., Cowley, R.A., Taylor, J.W., Bennington, S.M., 

“Reply to “Comment on ‘High-Energy Neutron 

Scattering from Hydrogen using a Direct Geometry 

Spectrometer,’ ” Phys. Rev. B 84(5), 056302 (2011). 

Stock, C., Rodriguez, E.E., Green, M.A., “Spin Fluctuations 

and Superconductivity in Powders of Fe1+xTe0.7Se0.3 as a 

Function of Interstitial Iron Concentration,” Phys. Rev. 

B 85(9), 094507 (2012). [CHRNS] 

Sturgeon, R.E., Lam, J.W., Windust, A., Grinberg, P., 

Zeisler, R.L., Oflaz, R., Paul, R.L., Lang, B.E., Fagan, 

J.A., Simard, B., Kingston, C.T., “Determination 

of Moisture Content of Single-wall Carbon 

Nanotubes,”Anal. Bioanal. Chem. 402, 429 (2012). 

Sun, L., Chen, X.-J., Guo, J., Gao, P., Huang, Q.-Z., 

Wang, H., Fang, M., Chen, X., Chen, G., Wu, Q., 

Zhang, C., Gu, D., Dong, X., Wang, L., Yang, K., 

Li, A., Dai, X., Mao, H.-K., Zhao, Z., “Re-emerging 

Superconductivity at 48 Kelvin in Iron Chalcogenides,” 

Nature 483, 67 (2012). 

Sun, Y., Wang, C., Huang, Q., Guo, Y., Chu, L., Arai, M., 

Yamaura, K., “Neutron Diffraction Study of Unusual 

Phase Separation in the Antiperovskite Nitride 

Mn3ZnN,” Inorg. Chem. 51(13), 7232 (2012). 

Takatsu, H., Kadowaki, H., Sato, T.J., Lynn, J.W., Tabata, 

Y., Yamazaki, T., Matsuhira, K., “Quantum Spin 

Fluctuations in the Spin Liquid State of Tb2Ti2O7,” J. 

Phys.: Condens. Matter 24, 052201 (2011). [CHRNS] 

Tao, R., “Electrorheology for Efficient Energy Production 

and Conservation,” J. Intell. Mater. Syst. Struct. 22, 

1667 (2011). 

Taraban, M.B., Feng, Y., Hammouda, B., Hyland, L.L., Yu, 

Y.B., “Chirality-Mediated Mechanical and Structural 

Properties of Oligopeptide Hydrogels,” Chem. Mater. 

24, 2299 (2012). 

Thampy, V., Kang, J., Rodriguez-Rivera, J.A., Bao, W., Savici, 

A.T., Hu, J., Liu, T.J., Qian, B., Fobes, D., Mao, 

Z.Q., Fu, C.B., Chen, W.C., Ye, Q., Erwin, R.W., 

Gentile, T.R., Tesanovic, Z., Broholm, C., “Friedel-like 

Oscillations from Interstitial Iron in Superconducting 

Fe1+yTe0.62Se0.38,” Phys. Rev. Lett. 108(10), 107002 

(2012). [CHRNS] 

Publications
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 81 
Publications
 

Thomas, J.J., James, S., Ortega, J.A., Musso, S., Auzerais, 

F., Krakowiak, S.K.J., Akono, A., Ulm, F., Pellenq, 

R.J.M., “Fundamental Investigation of the Chemical 

and Mechanical Properties of High-Temperature-Cured 

Oilwell Cements,” in “Offshore Technology Conference 

Proc.” editor unknown, (Offshore Tech. Conf., April 

2012, Houston, TX.), (2012). 

Thomas, J.J., Allen, A.J., Jennings, H.M., “Density and 

Water Content of Nanoscale Solid C-S-H Formed in 

Alkali-Activated Slag (AAS) Paste and Implications 

for Chemical Shrinkage,” Cem. Concr. Res. 42, 377 

(2012). [CHRNS] 

Thompson, S.M., Ma, H.B., Wilson, C., “Investigation of a 

Flat-Plate Oscillating Heat Pipe with Tesla-Type Check 

Valves,” Exp. Therm. Fluid Sci. 35, 1265 (2011). 

Toft-Petersen, R., Andersen, N.H., Li, H., Li, J., Tian, W., 

Bud’ko, S.L., Jensen, T.B.S., Niedermayer, C., Laver, 

M., Zaharko, O., Lynn, J.W., Vaknin, D., “Magnetic 

Phase Diagram of Magnetoelectric LiMnPO4,” Phys. 

Rev. B 85(22), 224415 (2012). 

Tomiyasu, K., Crawford, M.K., Adroja, D.T., Manuel, P., 

Tominaga, A., Hara, S., Sato, H., Watanabe, T., Ikeda, 

S.I., Lynn, J.W., Iwasa, K., Yamada, K., “Molecular 

Spin-Orbit Excitations in the Jeff = 1⁄2 Frustrated Spinel 

GeCo2O4,” Phys. Rev. B 84(5), 054405 (2011). 

Top, A., Zhong, S., Yan, C., Roberts, C.J., Pochan, D.J., 

Kiick, K.L., “Controlling Assembly of Helical 

Polypeptides via PEGylation Strategies,” Soft Matter 7, 

9758 (2011). 

Toppozini, L., Armstrong, C.L., Kaye, M.D., Tyagi, M., 

Jenkins, T., Rheinstädter, M.C., “Hydration Water 

Freezing in Single Supported Lipid Bilayers,” ISRN 

Biophysics 2012, 520307 (2012). [CHRNS] 

Trivelpiece, C.L., Petrunis, J.H., Pantano, C.G., Downing, 

R.G., “Glass Surface Layer Density by Neutron Depth 

Profiling,” International Journal of Applied Glass 

Science 3(2), 137 (2012). 

Tsao, C.-S., Liu, Y., Chuang, H.-Y., Tseng, H.-H., Chen, 

T.-Y., Chen, C.-C., Yu, M.-S., Li, Q., Lueking, A., 

Chen, S.-H., “Hydrogen Spillover Effect of Pt-Doped 

Activated Carbon Studied by Inelastic Neutron 

Scattering,” J. Phys. Chem. Lett. 2, 2322 (2011). 

Valenza, II, J.J., Thomas, J.J., “Permeability and Elastic 

Modulus of Cement Paste as a Function of Curing 

Temperature,” Cem. Concr. Res. 42, 440 (2012). 

[CHRNS] 

Verdal, N., Wu, H., Udovic, T.J., Stavila, V., Zhou, W., 

Rush, J.J., “Evidence of a Transition to Reorientational 

Disorder in the Cubic Alkali-metal Dodecahydrocloso-dodecaborates,” J. Phys. Chem. Solids 184, 3110 

(2011). 

Verdal, N., Zhou, W., Stavila, V., Her, J.-H., Yousufuddin, 

M., Yildirim, T., Udovic, T.J., “Alkali and AlkalineEarth Metal Dodecahydro-closo-Dodecaborates: 

Probing Structural Variations via Neutron Vibrational 

Spectroscopy,” J. Alloys Compd. 509S, S694 (2011). 

-

Reorientations in Hexagonal LiBH4,” J. Phys. Chem. 

C 116, 1614 (2011). 

Verdal, N., Udovic, T.J., Rush, J.J., “The Nature of BH4 

Verdal, N., Udovic, T.J., Rush, J.J., “Correction to “The 

Nature of BH4 

- Reorientations in Hexagonal LiBH4,” 

J. Phys. Chem. C 116, 5275 (2012). [CHRNS] 

Von White, II,G., Mohammed, F.S., Kitchens, C.L., 

“Small- Angle Neutron Scattering Investigation of 

Gold Nanoparticle Clustering and Ligand Structure 

Under Antisolvent Conditions,” J. Phys. Chem. C 115, 

18397 (2011). 

Wang, C., Chu, L., Yao, Q., Sun, Y., Wu, M., Ding, L., 

Yan, J., Na, Y., Tang, W., Li, G., Huang, Q., Lynn, 

J.W., “Tuning the Range, Magnitude, and Sign of the 

Thermal Expansion in Intermetallic Mn3(Zn,M)xN 

(M = Ag,Ge),” Phys. Rev. B 85(22), 220103 (2012). 

Wang, H., Downing, R.G., Dura, J.A., Hussey, D.S., “In 

situ Neutron Techniques for Studying Lithium Ion 

Batteries,” in “Polymers for Energy Storage and Delivery: 

Polyelectrolytes for Batteries and Fuel Cells, Volume 

1096,” edited by Page, K., et al., (Americal Chemical 

Society, Washington, D.C.) Chap. 6, 91 (2012). 

Wang, M., Wang, M., Li, G.N., Huang, Q., Li, C.H., Tan, 

G.T., Zhang, C.L., Cao, H., Tian, W., Zhao, Y., Chen, 

Y.C., Lu, X.Y., Sheng, B., Luo, H.Q., Li, S.L., Fang, 

M.H., Zarestky, J.L., Ratcliff, W., Lumsden, M.D., 

Lynn, J.W., Dai, P., “Antiferromagnetic Order and 

Superlattice Structure in Nonsuperconducting and 

Superconducting RbyFe1.6+xSe2,” Phys. Rev. B 84(9), 

094504 (2011). 

82 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
Wang, S.-C., Mirarefi, P., Faraone, A., Lee, Jr.,.C.T., “LightControlled Protein Dynamics Observed with Neutron 

Spin Echo Measurements,” Biochemistry 50, 8150 

(2011). [CHRNS] 

Wang, X.-M., Wang, C.-H., Wu, M.M., Wang, Y.X., Jing, 

X.-P., “O/N Ordering in the Structure of Ca3Si2O4N2 

and the Luminescence Properties of the Ce3+ Doped 

Material,” J. Mater. Chem. 22, 3388 (2012). 

Watson, B.J., Hammouda, B., Briber, R.M., Hutcheson, 

S.W., “Influence of Organic Liquids on the 

Nanostructure of Precipitated Cellulose,” J. Appl. 

Polym. Sci., in press. [CHRNS] 

Weber, F., Rosenkranz, S., Castellan, J.-P., Osborn, R., 

Zheng, H., Mitchell, J.F., Chen, Y., Chi, S., Lynn, 

J.W., Reznik, D., “Response of Acoustic Phonons to 

Charge and Orbital order in the 50 % Doped Bilayer 

Manganite LaSr2Mn2O7,” Phys. Rev. Lett. 107(20), 

207202 (2011). 

Weigandt, K.M., Porcar, L., Pozzo, D.C., “In situ Neutron 

Scattering Study of Structural Transitions in Fibrin 

Networks under Shear Deformation,” Soft Matter 7, 

9992 (2011). 

Weinrich, M., Nanda, H., Worcester, D.L., Majkrzak, C.F., 

Maranville, B.B., Bezrukov, S.M., “Halothane Changes 

the Domain Structure of a Binary Lipid Membrane,” 

Langmuir 28, 4723 (2012). 

Wen, J., Xu, Z., Xu, G., Jie, Q., Hücker, M., Zheludev, A., 

Tian, W., Winn, B.L., Zarestky, J.L., Singh, D. K., 

Hong, T., Li, Q., Gu, G., Tranquada, J.M., “Probing the 

Connections Between Superconductivity, Stripe Order, 

and Structure in La1.905Ba0.095Cu1-yZnyO4,” Phys. Rev. 

B 85(13), 134512 (2012). [CHRNS] 

Wen, J., Jie, Q., Li, Q., Hücker, M., Zimmermann, M.v., 

Han, S.J., Xu, Z., Singh, D.K., Konik, R.M., Zhang, 

L., Gu, G., Tranquada, J.M., “Uniaxial Linear 

Resistivity of Superconducting La1.905Ba0.095CuO4 

Induced by an External Magnetic Field,” Phys. Rev. 

B 85(13), 134513 (2012). [CHRNS] 

White, J.S., Heslop, R.W., Holmes, A.T., Forgan, E.M., 

Hinkov, V., Egetenmeyer, N., Gavilano, J.L., Laver, 

M., Dewhurst, C.D., Cubitt, R., Erb, A., “MagneticField- Induced Nonlocal Effects on the Vortex 

Interactions in Twin-Free YB2Cu3O7,” Phys. Rev. 

B 84(10), 104519 (2011). 

Williams, J.G., Gilliam, D.M., “Thermal Neutron 

Standards,” Metrologia 48, S254 (2011). 

Wolff, M., Pálsson, G.K., Korelis, P.T., Dura, J.A., Majkrzak, 

C., Hjörvarsson, B., “Hydrogen Distribution in Nb/Ta 

Superlattices,” J. Phys.: Condens. Matter 24, 255306 

(2012). 

Wong-Ng, W., Yang, Z., Liu, G., Huang, Q., Cook, 

L.P., Diwanji, S., Lucas, C., Jang, M.-H., Kaduk, 

J.A., “Chemical Interactions of the Ba2YCu3O6+x 

Superconductor with Coated Conductor Buffer Layers,” 

in “Advances and Applications in Electroceramics, 

Volume 226,” edited by Nair, K.M., Jia, Q., Pryia, S. 

(John Wiley & Sons, Inc. Hoboken, NJ), Chap. 19, 

173 (2012). 

Wong-Ng, W., Kaduk, J.A., Espinal, L., Suchomel, 

M.R., Allen, A.J., Wu, H., “High-Resolution 

Synchrotron X-ray Powder Diffraction Study of bis(2­

methylimidazolyl)-zinc C8H10N4Zn (ZIF-8),” Powder 

Diffr. 26(3), 234 (2011). 

Wong-Ng, W., Lu, T., Xie, W., Tang, W.H., Kaduk, J.A., 

Huang, Q., Yan, Y., Chattopadhyay, S., Tang, X., 

Tritt, T., “Phase Diagram, Crystal Chemistry and 

Thermoelectric Properties of Compounds in the Ca-CoZn-O System,” J. Solid State Chem. 184, 2159 (2011). 

Wong-Ng, W., Huang, Q., Levin, I., Woicik, J.C., Shi, X., 

Yang, J., Kaduk, J.A., “Crystal Structure and Powder 

Diffraction Reference Pattern of Type I Clathrate 

Ba8Ni4Ge42,” Powder Diffr. 27(1), 25 (2012). 

Woodka, A.C., Butler, P.D., Porcar, L., Farago, B., Nagao, 

M., “Lipid Bilayers and Membrane Dynamics: Insight 

into Thickness Fluctuations,” Phys. Rev. Lett. 109(5), 

058102 (2012). [CHRNS] 

Wright, N.T., Raththagala, M., Hemmis, C.W., Edwards, 

S., Curtis, J.E., Krueger, S., Schildbach, J.F., “Solution 

Structure and Small Angle Scattering Analysis of Tral 

(381-569),” Proteins, in press. 

Wu, B., Li, X., Do, C., Kim, T.-H., Shew, C.-Y., Liu, Y., 

Yang, J., Hong, K., Porcar, L., Chen, C.-Y., Liu, E.L., 

Smith, G.S., Herwig, K.W., Chen, W.-R., “Spatial 

Distribution of Intra-Molecular Water and Polymeric 

Components in Polyelectrolyte Dendrimers Revealed 

by Small Angle Scattering Investigations,” J. Chem. 

Phys. 135(14), 144903 (2011). 

Publications
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 83 
Publications
 

Wu, B., Kerkeni, B., Egami, T., Do, C., Liu, Y., Wang, Y., 

Porcar, L., Hong, K., Smith, S.C., Liu, E.L., Smith, 

G.S., Chen, W.-R., “Structured Water in Polyelectrolyte 

Dendrimers: Understanding Small Angle Neutron 

Scattering Results through Atomistic Simulation,” J. 

Chem. Phys. 136(14), 14490 (2012). 

Wu, H., Zhou, W., Pinkerton, F.E., Udovic, T.J., Yildirim, 

T., Rush, J.J., “Metal Hydrazinoborane LiN2H3BH3 

and LiN2H3BH3•2N2H4BH3: Crystal Structures and 

High-Extent Dehydrogenation,” Energy Environ. 

Sci. 5, 7531 (2012). 

Wu, L.S., Janssen, Y., Marques, C., Bennett, M.C., Kim, 

M.S., Park, K., Chi, S., Lynn, J.W., Lorusso, G., 

Biasiol, G., Aronson, M.C., “Magnetic Field Tuning 

of Antiferromagnetic Yb3Pt4,” Phys. Rev. B 84(13), 

134409 (2011). 

Xiang, S., He, Y., Zhang, Z., Wu, H., Zhou, W., Krishna, 

R., Chen, B., “Microporous Metal-Organic Framework 

with Potential for Carbon Dioxide Capture at Ambient 

Conditions,” Nat. Commun. 3(954), 1 (2012). 

Xu, Z., Wen, J., Xu, G., Chi, S., Ku, W., Gu, G., Tranquada, 

J.M., “Local-moment Magnetism in Superconducting 

FeTe0.35Se0.65 as Seen via Inelastic Neutron Scattering,” 

Phys. Rev. B 84(5), 052506 (2011). 

Yamada, T., Yonamine, R., Yamada, T., Kitagawa, H., Tyagi, 

M., Nagao, M., Yamamuro, O., “Quasi-elastic Neutron 

Scattering Studies on Dynamics of Water Confined in 

Nanoporous Copper Rubeanate Hydrates,” J. Phys. 

Chem. B 115, 13563 (2011). [CHRNS] 

Yamamuro, O., Yamada, T., Kofu, M., Nakakoshi, M., 

Nagao, M., “Hierarchical Structure and Dynamics 

of an Ionic Liquid 1-Octyl-3-methylimidazolium 

Chloride,” J. Chem. Phys. 135(5), 054508 (2011). 

[CHRNS] 

Yáñez-Vilar, S., Mun, E.D., Zapf, V.S., Ueland, B.G., 

Gardner, J.S., Thompson, J.D., Singleton, J., SánchezAndújar, M., Mira, J., Biskup, N., Señarís-Rodríguez, 

M.A., Batista, C.D., “Multiferroic Behaviour in the 

New Double-Perovskite Lu2MnCoO6,” Phys. Rev. B 

84(13), 134427 (2011). 

Yang, J.B., Yang, Y.B., Chen, X.G., Ma, X.B., Han, J.Z., 

Yang, Y.C., Guo, S., Yan, A.R., Huang, Q. Z., Wu, 

M.M., Chen, D.F., “Anisotropic Nanocrystalline MnBi 

with High Coercivity at High Temperature,” Appl. 

Phys. Lett. 99(8), 082505 (2011). 

Yang, K., Xu, C., Huang, L., Zou, L., Wang, H., “Hybrid 

Nanostructure Heterojunction Solar Cells Fabricated 

using Vertically Aligned ZnO Nanotubes Grown on 

Reduced Graphene Oxide,” Nanotechnology 22, 

405401 (2011). 

Yang, Y-Q., Li, G.-N., Wang, T., Huang, Q.-Z., Gao, Q.-Q., 

Li, J.-B., Liu, G.-Y., Luo, J., Rao, G.-H., “Neutron 

Diffraction Study on Composite Compound Nd2Co7,” 

Chin. Phys. B 20(10), 106101 (2011). 

Yankova, T., Hüvonen, D., Mühlbauer, S., Schmidiger, D., 

Wulf, E., Zhao, S., Zheludev, A., Hong, T., Garlea, 

V.O., Custelcean, R., Ehlers, G., “Crystals for Neutron 

Scattering Studies of Quantum Magnetism,” Philos. 

Mag. 92(19-21), 2629 (2012). 

Yao, J., Brunetta, C.D., Aitken, J.A., “Suppression of 

Antiferromagnetic Interactions through Cu Vacancies 

in Mn-Substituted CuInSe2 Chalcopyrites,” J. Phys.: 

Condens. Matter 24(8), 086006 (2012). 

Yao, J., Rudyk, B.W., Brunetta, C.D., Knorr, K.B., Figore, 

H.A., Mar, A., Aitken, J.A., “Mn Incorporation in 

CuInS2 Chalcopyrites: Structure, Magnetism and 

Optical Properties,” Mater. Chem. Phys., in press. 

Yaron, P.N., Holt, B.D., Short, P.A., Lösche, M., Islam, M.F., 

Dahl, K.N., “Single Wall Carbon Nanotubes Enter 

Cells by Endocytosis and not Membrane Penetration,” 

Journal of Nanobiotechnology 9(45), 1 (2011). 

Ye, F., Fishman, R.S., Haraldsen, J., Lorenz, B., Chu, C.W., 

Kimura, T., “Spin Dynamics in the Multiferroic 

Materials (invited),” J. Appl. Phys. 111(7), 07E137 

(2012). [CHRNS] 

Yeo, J., Kim, S.Y., Kim, S., Ryu, D.Y., Kim, T.-H., Park, 

M.J., “Mechanically and Structurally Robust Sulfonated 

Block Copolymer Membranes for Water Purification 

Applications,” Nanotechnology 23, 245703 (2012). 

84 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
Yeon, J., Kim, S.-H., Green, M.A., Bhatti, K.P., Leighton, C., 

Halasyamani, P.S., “Syntheses, Crystal Structures, and 

Characterization of Two New Tl+

-Cu2+-Te6+ Oxides: 

Tl4CuTeO6 and Tl6CuTe2O20,” J. Solid State Chem., 

in press. 

Yi, Z., Miao, Y., Baudry, J., Jain, N., Smith, J.C., “Derivation 

of Mean-Square Displacements for Protein Dynamics 

from Elastic Incoherent Neutron Scattering,” J. Phys. 

Chem. B 116, 5028 (2012). 

Yi, Z., Nagao, M., Bossev, D.P., “Effect of Charged 

Lidocaine on Static and Dynamic Properties of Model 

Bio- Membranes,” Biophys. Chem. 160, 20 (2012). 

[CHRNS] 

Yoon, I., Wilson, C., Borgmeyer, B., Winholtz, R.A., 

Ma, H.B., Jacobson, D.L., Hussey, D.S., “Neutron 

Phase Volumetry and Temperature Observations in 

an Oscillating Heat Pipe,” International Journal of 

Thermal Sciences, in press. 

Yoonessi, M., Heinz, H., Dang, T.D., Bai, Z., “Morphology 

of Sulfonated Polyarylenethioethersulfone Random 

Copolymer Series as Proton Exchange Fuel Cells 

Membranes by Small Angle Neutron Scattering,” 

Polymer 52, 5615 (2011). 

Yu, J., Phelan, D., Louca, D., “Spin-state Transitions in 

PrCoO3 Investigated by Neutron Scattering,” Phys. 

Rev. B 84(13), 132410 (2011). 

Yu, L.L., Jarrett, J.M., Davis, W.C., Kilpatrick, E.L., Oflaz, 

R., Turk, G.C., Leber, D.D., Valentin, L., MorelEspinosa, M., Blount, B.C., “Characterization of 

Perchlorate in a New Frozen Human Urine Standard 

Reference Material,” Anal. Bioanal. Chem., in press. 

Yun, S.I., Cao, L., Kang, T.-B., Huh, M., Gauthier, M., 

“Morphology of Polystyrene Core-dPoly(ethylene 

oxide) Shell Arborescent Copolymer Micelles 

from Small-Angle Neutron Scattering Analysis,” J. 

Macromol. Sci., Phys.50, 2318 (2011). 

Zeisler, R., Oflaz, R., Paul, R.L., Fagan, J. A., “Use of 

Neutron Activation Analysis for the Characterization of 

Single-Wall Carbon Nanotube Materials,” J. Radioanal. 

Nucl. Chem. 291, 561 (2012). 

Zhao, J., Niestemski, F.C., Kunwar, S., Li, S. Steffens, P. 

Hiess, A. Kang, H.J., Wilson, S.D., Wang, Z., Dai P. 

and Madhavan, V. “Electron-Spin Excitation Coupling 

in an Electron-Doped Copper Oxide Superconductor,” 

Nature Physics 7, 719 (2011). [CHRNS] 

Zhang, C., Wang, M., Luo, H., Wang, M., Liu, M., Zhao, 

J., Abernathy, D.L., Maier, T.A., Marty, K., Lumsden, 

M.D., Chi, S., Chang, S., Rodriguez-Rivera, J.A., 

Lynn, J.W., Xiang, T., Hu, J., Dai, P., “Neutron 

Scattering Studies of Spin Excitations in Hole-Doped 

Ba0.67K0.33Fe2As2 Superconductor,” Scientific Reports 

1(115), 1 (2011). [CHRNS] 

Zhang, Y., Faraone, A., Kamitakahara, W.A., Liu, K.-H., 

Mou, C.-Y., Leão, J.B., Chang, S., Chen, S.-H., “Reply 

to Soper: Density Measurement of Confined Water 

with Neutron Scattering,” PNAS 108(47), E1193 

(2011). [CHRNS] 

Zhang, Y., Tyagi, M., Mamontov, E., Chen, S.-H., “QuasiElastic Neutron Scattering Studies of the Slow 

Dynamics of Supercooled and Glassy Aspirin,” J. Phys.: 

Condens. Matter 24, 064112 (2012). [CHRNS] 

Zhou, H.D., Bramwell, S.T., Cheng, J.G., Wiebe, C.R., Li, 

G., Balicas, L., Bloxsom, J.A., Silverstein, H.J., Zhou, 

J.S., Goodenough, J.B., Gardner, J.S., “High Pressure 

Route to Generate Magnetic Monopole Dimers in Spin 

Ice,” Nat. Commun. 2(478), 1 (2011). 

Zhou, H.D., Cheng, J.G., Hallas, A.M., Wiebe, C.R., Li, G., 

Balicas, L., Zhou, J.S., Goodenough, J.B., Gardner, J.S., 

Choi, E.S., “Chemical Pressure Effects on Pyrochlore 

Spin Ice,” Phys. Rev. Lett. 108(20), 207206 (2012). 

Publications
 

2012 ACCOMPLISHMENTS AND OPPORTUNITIES 85 
Instruments and Contacts
 

Instruments and Contacts
 

Instruments and Contacts: (name, tel. (301) 975-XXXX, 

email address) 

High resolution powder diffractometer (BT-1): 

J.K. Stalick, 6223, judith.stalick@nist.gov 

H. Wu, 2387, hui.wu@nist.gov 

Q.Z. Huang, 6164, qing.huang@nist.gov 

Residual stress diffractometer (BT-8): 

T. Gnaeupel-Herold, 5380, thomas.gnaeupel-herold@nist.gov 

30-m SANS instrument (NG-7): 

Yun Liu, 6235, yun.liu@nist.gov
 

Paul Butler, 2028, paul.butler@nist.gov
 

Jeff Krzywon, 6650, jkrzywon@nist.gov
 

30-m SANS instrument (NG-3) (CHRNS): 

Boualem Hammouda, 3961, hammouda@nist.gov
 

Steve Kline, 6243, steven.kline@nist.gov
 

Susan Krueger, 6734, susan.krueger@nist.gov
 

Cedric Gagnon, 2020, cedric.gagnon@nist.gov
 

10-m SANS instrument (nSoft) (NGBl): 

Ron Jones, 4624, ronald.jones@nist.gov
 

Katie Weigandt, 8396, kathleen.wiegandt@nist.gov
 

USANS, Perfect Crystal SANS (BT-5) (CHRNS): 

David Mildner, 6366, david.mildner@nist.gov
 

Matt Wasbrough, 6017, matthew.wasbrough@nist.gov
 

Paul Butler, 2028, paul.butler@nist.gov
 

Polarized Beam Reflectometer/Diffractometer (NG-D): 

B.J. Kirby, 8395, brian.kirby@nist.gov 

J.A. Borchers, 6597, julie.borchers@nist.gov 

C.F. Majkrzak, 5251, cmajkrzak@nist.gov 

MAGIk, Off-Specular Reflectometer (NG-D): 

B.B. Maranville, 6034, brian.maranville@nist.gov 

J.A. Dura, 6251, joseph.dura@nist.gov 

Neutron reflectometer-horizontal sample (NG-7): 

S.K. Satija, 5250, satija@nist.gov 

B. Akgun, 6469, bulent.akgun@nist.gov 

Double-focusing triple-axis Spectrometer (BT-7): 

Y. Zhao, 2164, yang.zhao@nist.gov 

J. Helton, 4899, joel.helton@nist.gov 

J.W. Lynn, 6246, jeff.lynn@nist.gov 

SPINS, Spin-polarized triple-axis spectrometer (NG-5): 

D. Singh, 4863, deepak.singh@nist.gov 

L. Harriger, 8360, leland.harriger@nist.gov 

Triple-axis spectrometer (BT-4): 

W. Ratcliff, 4316, william.ratcliff@nist.gov 

FANS, Filter-analyzer neutron spectrometer (BT-4): 

T.J. Udovic, 6241, udovic@nist.gov 

DCS, Disk-chopper time-of-flight spectrometer (NG-4)(CHRNS): 

J.R.D. Copley, 5133, jcopley@nist.gov 

Y. Qiu., 3274, yiming.qiu@nist.gov 

C. M. Brown, 5134, craig.brown@nist.gov 

HFBS, High-flux backscattering spectrometer (NG-2) (CHRNS): 

M. Tyagi, 2046, madhusudan.tyagi@nist.gov 

W. Zhou, 8169, wei.zhou@nist.gov 

NSE, Neutron spin echo spectrometer (NG-5) (CHRNS): 

A. Faraone, 5254, antonio.faraone@nist.gov 

J.S. Gardner, 8396, jason.gardner@nist.gov 

M. Nagao, 5505, michihiro.nagao@nist.gov 

MACS, Multi-angle crystal spectrometer (BT-9) (CHRNS): 

J. Rodriguez, 6019, jose.rodriguez@nist.gov 

Cold-neutron prompt-gamma neutron activation analysis (NG-D): 

R.L. Paul, 6287, rpaul@nist.gov 

Thermal-neutron prompt-gamma activation analysis (VT-5): 

G. Downing, 3782, gregory.downing@nist.gov 

Other activation analysis facilities: 

G. Downing, 3782, gregory.downing@nist.gov 

Cold neutron depth profiling (NG-1): 

G. Downing, 3782, gregory.downing@nist.gov 

Neutron Imaging Station (BT-2): 

D. Jacobson, 6207, david.jacobson@nist.gov 

D. Hussey, 6465, daniel.hussey@nist.gov 

M. Arif, 6303, muhammad.arif@nist.gov 

Neutron interferometer (NG-7): 

M. Arif, 6303, muhammad.arif@nist.gov 

D. Jacobson, 6207, david.jacobson@nist.gov 

D. Hussey, 6465, daniel.hussey@nist.gov 

Fundamental neutron physics station (NG-6): 

NG-6M: M.S. Dewey, 4843, mdewey@nist.gov 

NG-6U: H.P. Mumm, 8355, pieter.mumm@nist.gov 

NG-6: J. Nico, 4663, nico@nist.gov 

Theory and modeling: 

J.E. Curtis, 3959, joseph.curtis@nist.gov 

T. Yildirim, 6228, taner@nist.gov 

Instruments Under Development 

vSANS instrument: 

J. Barker, 6732, john.barker@nist.gov 

C. Glinka, 6242, charles.glinka@nist.gov 

CANDOR, White-beam reflectometer/diffractometer: 

F. Heinrich, 4507, frank.heinrich@nist.gov 

C. Majkrzak, 5251, charles.majkrzak@nist.gov 

86 NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY – NIST CENTER FOR NEUTRON RESEARCH 
NIST Center For Neutron Research Contacts
 

Copies of annual reports, facility information, 

user information, And research proposal 

guidelines are available electronically. 

Please visit our website: 

http://www.ncnr.nist.gov 

For a paper copy of this report: 

Ron Cappelletti 

301-975-6221 

ron.cappelletti@nist.gov 

For general information on the facility: 

Rob Dimeo 

301-975-6210 

robert.dimeo@nist.gov 

Dan Neumann 

301-975-5252 

dan.neumann@nist.gov 

For information on visiting the 

facility and/or user access questions: 

Julie Keyser 

301-975-8200 

julie.keyser@nist.gov 

Mary Ann FitzGerald 

301-975-8200 

maryann.fitzgerald@nist.gov

For information on performing 

research at the facility: 

Bill Kamitakahara 

301-975-6878 

william.kamitakahara@nist.gov 

Facility address: 

NIST Center for Neutron Research 

National Institute of Standards and Technology 

100 Bureau Drive, Mail Stop 6100 

Gaithersburg, MD 20899-6100 USA