2 0 1 0

Accomplishments

and Opportunities

The NIST CENTER for NEUTRON RESEARCH

NIST SP 1110
This page intentionally blank.
ON THE COVER

Neutron intensity in a constant energy cut in the x,y plane at 4 meV 

for Q values ranging from 0 Å-1 to 

2 Å-1 displaying phonons and magnetic excitations in a compound 

of FeTe0.7Se0.3 at 30 K. Investigations in this class of materials are 

focused on the subtle interplay 

between superconductivity and magnetism. Data, courtesy of 

NCNR’s Songxue Chi, are from the MACS instrument...20 g of 

aligned sample, 2 hour scan.
2010 NIST Center for 

Neutron Research

Accomplishments 

and Opportunities

NIST Special Publication 1110

Robert M. Dimeo, Director

Ronald L. Cappelletti, Editor

December 2010

National Institute of Standards and Technology

Patrick Gallagher, Director

U.S. Department of Commerce

Gary Locke, Secretary
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 Publication 1110

Natl. Inst. Stand. Technol. Spec. Publ. 1110, 88 pages

(December 2010)

CODEN: NSPUE2

U.S. GOVERNMENT PRINTING OFFICE-WASHINGTON: 2010

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
Table of Contents

iv FOREWORD

1 THE NIST CENTER FOR NEUTRON RESEARCH

2 NIST CENTER FOR NEUTRON RESEARCH INSTRUMENTS

4 NCNR IMAGES 2010

HIGHLIGHTS

CONDENSED MATTER

6 Core-shell magnetic morphology of magnetite 

nanoparticles

8	 Electric field control of magnetization in multiferroic

HoMnO3: the importance of magnetic domains

10 Frustrated magnetism and superconductivity in 

Fe1+ySe0.4Te0.6

12 Lattice distortion and magnetic quantum phase 

transition in CeFeAs1-xPxO 

14 Tuning the magnetic and structural properties of 

Fe1+xTe

BIOLOGY

16	 Neutron reflectometry study of the conformation of

HIV Nef bound to lipid membranes

18 How does the stiffness of lipid vesicles change as they 

interact with pore-forming peptides?

20 Bilayer membrane dynamics in NSAID-phospholipid 

adducts

ENGINEERING

22 A method for the measurement of retained austenite 

content in steels

24	 Probing artificial muscles with neutrons

CHEMICAL PHYSICS

26 ‘Molecular headphones’, SANS and MD modeling of 

protein denaturing

28 Coordinatively-unsaturated metal-organic frameworks 

for hydrogen storage 

30 Graphite oxide framework (GOF) materials for 

hydrogen storage

32 New insight into the crystal structure of highly 

piezoelectric PZT: a single crystal diffraction study

34 Multiple filling of voids improves thermoelectric

efficiency of skutterudites

SOFT MATTER

36	 Observation of thickness fluctuations in surfactant

membranes

38 Neutron transmission measurements of concentration 

profiles in non-homogeneous shear flows

40 Mechanism of molecular exchange in copolymer 

dispersions

42 How does ionic liquid distribute between microphaseseparated domains of a block copolymer? 

NEUTRON PHYSICS

44 Decoherence-free neutron interferometry

ADVANCES IN MEASUREMENT

46 Software for biological soft condensed matter science

47 Following lithium through battery components and 

functioning prototypes

48 Peering inside: imaging an object’s interior while 

clarifying its elemental makeup

49 Time-resolved SANS with sub-millisecond resolution 

(t-SANS)

50 Elemental analysis of a single-wall carbon nanotube 

candidate reference material

51 NEUTRON SOURCE OPERATIONS

52 EXPANSION INITIATIVE

55 FACILITY DEVELOPMENT

58 SERVING THE SCIENCE AND TECHNOLOGY COMMUNITY

60 THE CENTER FOR HIGH RESOLUTION NEUTRON 

SCATTERING (CHRNS)

63 AWARDS 2010

65 PUBLICATIONS

80 INSTRUMENTS AND CONTACTS

CONTACTS (inside back cover)
iv

Foreword

I am pleased to present to you this year’s annual report for the NIST 

Center for Neutron Research, containing a sample of the NCNR’s recent 

accomplishments and opportunities in 2010. At this time last year, 

construction work for the NCNR Expansion Project was underway for the 

expanded guide hall and technical support building (TSB). A lot can happen 

in a year! The civil construction is complete and staff have moved into the 

TSB, now known as the “K-wing” of building 235. The guide hall extension, 

which will house both relocated and new cold neutron instruments, was 

empty when we took ownership of it in August, but now contains equipment 

for the Expansion including guide casings, shielding, and instrument 

components. And much more equipment is on its way.

Change was not only evident with the inauguration of the two new buildings 

but also in staffing. After six years of service to NCNR and NIST, Wade Richards, Chief of Reactor Operations and

Engineering, retired. Wade led the Reactor Operations group through a period of significant change and growth,

culminating with the successful relicensing in 2009. This was an outstanding apex to a noteworthy career. In 

order to carry on the tradition of excellence in reactor operations, Sean O’Kelly, who joined the NCNR in 2009, 

was appointed Chief of Reactor Operations and Engineering. Sean brings with him not only extensive technical 

knowledge but also significant experience managing a reactor facility.

It was yet another great year for facility operations thanks to our dedicated staff. The reactor operated at full power 

(20 MW) for 267 days, marking this year as one of the highest in source and instrument availability. Numerous

developments contributed to a successful year. In this report you will read about technical developments such as 

our growing 3He neutron spin filter program which is providing entirely new measurement capabilities for our

users. This technology is fast becoming a standard capability for neutron beam experiments as is evident in the 

rapidly growing number of experiments and published results. The quality of science done with NCNR facilities 

continues to be excellent and is reflected in resulting high impact publications. Innovations and developments

permitting users to more easily perform the best measurements can be attributed to many factors but the most 

important one is clearly our highly talented and dedicated staff. 

The upcoming year will be one of very intense activity. In order to carry out the reactor reliability enhancements 

that are part of the Expansion Project and the American Recovery and Reinvestment Act, the reactor will be shut 

down for 11 months starting in April 2011. During this time we will also undertake numerous instrumentation and 

beam delivery projects that will set the stage for the next phase of facility development at the NCNR. We have been

carefully planning the sequence of activities for some time to ensure that a new and improved facility is available to 

the scientific community on schedule.

As ever, the reason for the NCNR is the excellent science that comes from the many researchers who use our facility. 

I continue to enjoy walking through the facility and talking with our users about their latest exciting experiments. 

You will find specific research highlights in the pages that follow. I hope that you enjoy reading them as much as

I have.
NCNR 2010 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 in waste-storage glasses to magnetic domains in 

memory storage materials. The properties of neutrons 

(outlined below) 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 29 experiment stations: four provide 

high neutron flux positions for irradiation, and 25 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 pp. 52-54) 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 

merit-based access made available to the entire U.S. 

technological community. Each year, more than 2000 

research participants from government, industry, and 

academia from all areas of the country use the facility. 

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 pp. 60-62). 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.

Present guide hall and 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.
2NCNR Instruments

NIST Center for Neutron Research Instruments

BT-5 Perfect Crystal Ultra-Small Angle 

Neutron Scattering (USANS) Diffractometer 

for microstructure up to 10 nm, part of 

CHRNS.

BT-4 Filter Analyzer Neutron Spectrometer 

with cooled Be/Graphite filter analyzer for 

chemical spectroscopy.

BT-2 Neutron Imaging Facility for imaging 

hydrogenous matter in large components 

such as water in fuel cells and lubricants in 

engines, in partnership with General Motors.

BT-1 Powder Diffractometer with 32 detectors; incident wavelengths of 0.208 nm, 

0.154 nm, and 0.159 nm, with highest 

resolution of δd/d ≅ 8 x 10.

4 

-4 

BT-9 Thermal Triple Axis Spectrometer for 

measurements of excitations and structure in 

condensed matter.

BT-8 Residual Stress Diffractometer optimized 

for depth profiling of residual stresses in large 

components.

VT-5 Thermal Neutron Capture Prompt 

Gamma-ray Activation Analysis Instrument with 

a neutron fluence rate of 3 x 10 cm s used 

for quantitative elemental analysis of bulk 

materials. Generally used for the analysis of 

highly hydrogenous materials (≅1 % H) such 

as foods, oils, and biological materials.

BT-7 Thermal Triple Axis Spectrometer with 

large double focusing monochromator, and 

interchangeable analyzer/detectors systems. 

8 -2

The Center for High Resolution Neutron Scattering (CHRNS) is a partnership 

between NIST and the National Science Foundation that develops and 

operates neutron scattering instrumentation for use by the scientific community. The following instruments are part of the Center: 1 (USANS), 9 (MACS), 

13 (HFBS), 14 (NG-3 SANS), 15 (DCS), 22 (NSE), and 23 (SPINS).

[1] 

[4] 

[3] 

[2] 

[5]

[8]

[7]

[6]

[1] 

[4] 

[3] 

[2] 

[5] 

[8] [7] 

[6] 

[9] 

[12] 

[11] [10] 

[22] 

[21] 

[23] 

[25] 

[24]

-1
NCNR 2010 Accomplishments and Opportunities 3

NG-0 MACS cold neutron triple axis crystal 

spectrometer (being commissioned) with 

double focusing monochromator and 

multiple crystal analyzer/detectors that can 

be flexibly configured for several energies 

simultaneously or for high throughput at one 

energy, part of CHRNS. 

NG-1 Advanced Neutron Diffractometer / 

Reflectometer (AND/R) a vertical sample 

reflectometer with polarization analysis and 

off-specular reflection capabilities for measuring reflectivities down to 10 .

NG-1 Vertical Sample Reflectometer instrument with polarization analysis capability for 

measuring reflectivities down to 10 to 

determine subsurface structure.

NG-1 Cold Neutron Depth Profiling instrument for quantitative profiling of subsurface 

impurities.

NG-2 Backscattering Spectrometer (HFBS) 

high intensity inelastic scattering instrument 

with energy resolution < 1 μeV, for studies of 

motion in molecular and biological systems, 

part of CHRNS.

NG-3 30 m SANS for microstructure measurements, part of CHRNS.

NG-4 Disk Chopper Time-of-Flight Spectrometer for studies of diffusive motions and 

low energy dynamics of materials. Wavelengths from ≅ 0.18 nm to 2.0 nm give 

corresponding energy resolutions from 

≅ 2 meV to < 10 μeV, part of CHRNS.

NG-6 Neutron Physics Station offering three 

cold neutron beams having wavelengths of 

0.5 nm, 0.9 nm, and “white” that are available for fundamental neutron physics experiments.

NG-7 30 m SANS for microstructure measurements, in partnership with NIST, and 

ExxonMobil.

NG-6 Neutron Physics Test Bed for developing measurement techniques and detectors.

NG-7 Prompt Gamma Activation Analysis, 

cold neutron fluxes allow detection limit for 

H of 1 μg to 10 μg, depending on the matrix. 

Focused beams are available for profiling.

NG-5 Neutron Spin-Echo Spectrometer 

(NSE) for measuring dynamics from 100 ns 

to 10 ps, in partnership with ExxonMobil, 

part of CHRNS.

NG-5 Spin-Polarized Triple Axis Spectrometer (SPINS) using cold neutrons with 

position sensitive detector capability for 

high-resolution studies, part of CHRNS.

NG-7 Neutron Interferometry and Optics 

Station with perfect crystal silicon interferometer. A vibration isolation system provides 

exceptional phase stability and fringe visibility.

NG-7 Horizontal Sample Reflectometer 

allows reflectivity measurements of free 

surfaces, liquid/vapor interfaces, as well as 

polymer coatings.

-8 

-8 

[9] 

[12]

[11] 

[10] 

[13]

[16-18]

[15]

[14]

[19]

[22]

[21]

[20]

[23]

[25]

[24]

[13] 

[16-18] 

[15] 

[14] 

[19] 

 

[20] 
4NCNR Images 2010

NCNR Images 2010

NCNR’s Juscelino Leão and middle school teacher Lauren 

Rogers look for crystals emerging from solution.

Wow! NCNR Summer School students encounter great 

data!

Alex Ye, SHIP student, developed a crystal orientation 

program with NCNR’s William Ratcliff.

Chuck Majkrzak demonstrates diffraction and shows an 

image of a wreath-like macromolecule.

Cabot Corp’s Jennifer Gough-Belleau prepares samples for 

a SANS/USANS measurement.

NCNR’s Antonio Faraone lends a NSE hand to ORNL’s Gerot 

Rothner and Dave Wesolowski.

Four generations of Reactor Operations Chiefs: Sean O’Kelly 

(present), Wade Richards, Sy Weiss and Tawfik Raby (original). 

Don’t try this at home, Dr. Lynn warns. You have to be a 

professional to shatter rose petals with liquid nitrogen. 

Safety glasses, everyone?
NCNR 2010 Accomplishments and Opportunities 5

Springtime at the NCNR

Really! There was a neutron there just 15 minutes ago! But young 

scientist Nathan Wade remains skeptical.

Notre Dame’s Morton Eskildsen applies SANS to reveal the 

metastable vortex phases in MgB2.

Does water move in waste-storage glass? Ask PNNL’s Kyle Alvine.

NCNR, including expansion buildings, as seen from the air, Sept. 18, 2010.

NIST PECASE awardees Craig Brown (NCNR) and Dean 

De Longchamp (Polymers) flank Presidential Science 

Advisor, Jon Holdren.
6Condensed Matter

6

Core-shell magnetic morphology of magnetite 

nanoparticles

K.L. Krycka1, R.A. Booth2, C.R. Hogg2, Y. Ijiri3, J.A. Borchers1, W.C. Chen1,4, S.M.Watson1, M. Laver5, 

T.R. Gentile1, L.R. Dedon3, S. Harris3, J.J. Rhyne6, and S. A. Majetich2

Magnetic nanoparticles hold great promise 

for applications as diverse as hyperthermic 

treatment of cancer (requiring a high degree of 

co-operative magnetic interaction) to compact 

data storage (where individual bits must act 

independently). However, this long-range, collective 

magnetic behavior is affected not only by the 

concentration and distance between particles, 

but also by their internal magnetic structure or 

morphology. Little is known about this internal 

magnetic response to magnetic stimuli, especially 

of those embedded deep within a nanoparticle 

assembly, since conventional probes either 

measure only the total net magnetic moment or 

are surface limited. In this article we highlight a 

novel application of small-angle neutron scattering 

(SANS) with polarization analysis to measure

the 3D magnetic morphology for a collection of 

nanoparticles [1]. Applied to 9 nm magnetite 

nanoparticles [2] closely packed together into facecentered cubic (FCC) crystal lattice, this technique 

revealed an unexpected magnetic core-shell 

morphology under conditions for which all the 

magnetic moments nominally appear to be aligned or 

“saturated” using convention probes.

Magnetite (Fe3O4) was long ago discovered as 

lodestone used for making compasses and has a 

magnetic moment about one-fifth that of iron. It is

biocompatible and resistant to oxidation, making 

it an ideal candidate for biomedical applications. 

Recent developments allow chemists to tailor the 

size of the spherical nanoparticles they produce with

high precision so each one looks nearly identical 

(less than 10 % full width half maximum in diameter 

variation) and to array them into highly ordered 

nanoparticle crystals. Intriguingly, the smaller the 

nanoparticles become, the less magnetic moment 

they contain per mass in comparison with magnetite 

in macroscopic form. This has widely been attributed to 

surface disordering, but direct proof has remained elusive.

SANS is ideal probe of nanoscale magnetism because it 

is highly penetrating (not surface limited) and it scatters 

from both nuclear and magnetic structures with subnanometer resolution. Neutrons have a spin which can be 

made to align parallel (+) or anti-parallel (−) to a particular

direction with application of a small guide field and

appropriate optics. By analyzing the spin of the neutrons

after they have scattered from the sample of interest, that 

is whether they remain in the same orientation (denoted 

++ and − −) or if they flip 180o (+ − and − +), we have

developed an analytical approach that uniquely separates 

the nuclear scattering (N2) from the magnetic moments 

aligned with the neutron polarization axis (M2

||) and those 

perpendicular to it (M2^) [1].

The scattering patterns of Fig. 1 were taken in a nominally 

saturating field of 1.2 T at 200 K, cold by human standards,

but well above the blocking temperature at which the 

magnetic moments would be expected to be “frozen” into

place. Moving away from the beam stop (seen as a central 

hole) the size of the features measured decrease as

Q = 2p/distance. In non spin-flip scattering a structural

ring at 0.080 Å-1 originates from the (111) reflection of the

face-centered cubic arrangement of the nanoparticles. 

Scattering from magnetic moments aligned along the 

applied field direction (horizontal) either add to or subtract

from this ring (− − and ++, respectively) along the vertical

direction (Fig. 1a and 1c). Conversely, spin-flip scattering

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

2Carnegie Mellon University, Pittsburgh, PA

3Oberlin College, Oberlin, OH 44074 4University of Maryland, College Park, MD 20742

5Paul Scherrer Institute, Villigen, Switzerland

6Los Alamos National Laboratory, Los Alamos, NM 87545

FIGURE 1: Two-dimensional SANS images (shown here at 1.2 T, 200 

K) taken at NCNR beam line NG3. Non spin-flip data (a and c) are 

dominated by a nuclear Bragg peak at 0.080 Å-1, while spin-flip (b) is 

entirely magnetic.
NCNR 2010 Accomplishments and Opportunities 7

is entirely magnetic (steering wheel pattern of Fig. 1b). 

M2^ can be observed along the horizontal and vertical

directions, while at 45°, 135°, 225°, and 315° from the 

horizontal, the spin-flip scattering is dominated by M2

||. To 

further analyze each component we process sector cuts of

+/− 10 degrees along each of the axes discussed to produce

Fig. 2. Notice how much stronger the nuclear peak is than 

the magnetic peak – this is why polarization analysis is key.

To model our data we have to take into account both 

the shape of the nanoparticles (form factor) and they 

way in which they pack together (structure factor). The 

models used to fit the data are shown as solid lines in

Fig. 2. N2 is modeled by spheres 9 nm in diameter, while 

M2

|| is modeled by a 7 nm diameter sphere of moments 

pointing along the applied field direction. In both of

these cases the nanoparticles exhibit the long-range 

packing from being assembled into FCC crystallites. M2^, 

however, is modeled by a 1 nm thick shell of magnetic 

spins pointed perpendicular to the applied field. These

M2^ shells additionally form clusters, or domains, of ≈

10 nanoparticles that select a common perpendicular 

orientation. Together, this model (Fig. 3) fully explains 

where the missing moments go and rules out surface 

disordering [1].

FIGURE 2: Data are scaled so that the N2 Bragg peak height is 1000. 

(a) Note the intensity difference between N2 (left axis) and M2

|| (right 

axis) peaks at 0.08 Å-1. (b) Note the M2^ dip at 0.075 Å-1, a value that 

constrains the shell thickness.

Furthermore, we have found that it is possible to modify 

the thickness of this magnetic shell canted perpendicular 

to the applied field using temperature and field. Holding

the field at 1.2 T, the shell was found to be 1.5 nm thick

between 300 K and 320 K; at 160 K to 200 K it was 1.0 nm 

thick, and at 10 K the signature of a shell was not observed. 

At 300 K in remanence (only a 0.005 T polarization

guide) the nanoparticles feel no intra-particle magnetic 

interactions nor experience the effects of applied field.

Neither ordered nor disordered shells are observed. Thus, 

the magnetic shells observed under high field conditions

are magnetically induced rather than structural in origin. 

We speculate that this unexpected magnetic core-shell

phenomenon results from the combination of surface 

anisotropy [3] (i.e., the tendency for spins at a surface to 

point away from the interior) and the presence of closelypacked nearest neighbor nanoparticles that forces these 

outward-pointing surface spins to collectively order.

In conclusion, polarization analyzed SANS revealed

that the missing magnetism from closely-packed 

magnetite nanoparticles subjected to a high magnetic 

field environment reappears as ordered, magnetic shells

canted perpendicular to the applied field. The shells

exhibit a collective behavior over ≈ 10 nanoparticles, and

their thickness varies with temperature. This discovery is 

particularly exciting because it suggests a possible new 

mechanism by which to tailor magnetic interparticle “crosstalk” without necessarily altering nanoparticle packing.

References

[1] K.L. Krycka et al., Phys. Rev. Lett. 104, 207203 (2010).

[2] S. Sun et al., J. Am. Chem. Soc. 126, 273 (2004).

[3] L. Berger et al., Phys. Rev. B 77, 104431 (2008).

FIGURE 3: The data in Fig. 2a and 2b are fit (solid lines) by a model 

shown here schematically. It consists of a 7 nm diameter core that 

magnetically follows the applied field (blue arrow) and a 1 nm thick 

shell that is canted perpendicular to it.
8Condensed Matter

8

Electric field control of magnetization in multiferroic 

HoMnO3: the importance of magnetic domains

B. G. Ueland1, J. W. Lynn1, M. Laver1,2, Y. J. Choi3, S.-W. Cheong3

Multiferroics are materials with coexisting types of ferroic order (e.g., ferroelectricity (FE), 

magnetic order, or ferroelasticity.) Multiferroics that 

possess coupling between FE and magnetic order are 

very rare but are of particular interest both from a 

scientific viewpoint and for applications because they

offer the possibility of electrically manipulating their 

magnetization or magnetically manipulating their

electric polarization. HoMnO3 is such a multiferroic, 

with a FE transition of 850 K, antiferromagnetic 

(AFM) order of the Mn3+ at TN = 72 K, and two Mn

spin reorientation transitions at TSR = 40 K and

THo ≈ 5 K. Anomalies in the dielectric susceptibility

at these various magnetic transitions indicate that 

coupling exists between the FE and AFM order 

[1,2,3], with the most striking result coming from 

optical experiments that claim bulk ferromagnetic 

order is induced and reversibly altered through 

application of an electric field [2].

Surprisingly however, recent x-ray and neutron 

scattering experiments have found no evidence 

for any electric field induced ferromagnetism

[4,5]. Dielectric function studies have shown the 

importance of coupling between AFM and FE 

domain walls in this and similar materials [3], and 

it is possible for a net magnetization to arise from

uncompensated spins within AFM domain walls, 

which may explain the previously observed electric 

field induced magnetization. To shed light on this

problem, we have performed small angle neutron 

scattering (SANS) experiments while applying 

electric fields to search for any net magnetization

occurring within AFM domain walls. We indeed find

magnetic scattering in this large length scale regime 

that is electric-field sensitive, providing a possible

explanation for the previously observed electric field

induced magnetization [6].

Fig. 1a shows the temperature dependence of the 

total counts on the SANS 2-D detector normalized to

the incident flux. The counts increase with decreasing

temperature, level off between 40 K ≤ T ≤ 150 K, and

then increase more quickly below TSR, indicating that 

additional SANS occurs below TSR. After subtracting 

T = 150 K data to eliminate contributions from structural

scattering and then averaging over the 2D SANS data we 

obtain the average scattering cross section, [dS/dW](|Q|) 

(not shown). At each temperature, the average cross section 

decreases with increasing |Q|, and is larger at lower 

temperatures, for low |Q|. To illustrate this point, we plot 

[dS/dW](|Q|=0.0064 Å-1) as a function of temperature and 

see in Fig. 1b that it increases with decreasing temperature 

upon cooling below TSR, indicating that the similar rise in 

Fig. 1a may possess a component coming from magnetic 

scattering.

Fig. 1c shows that the average scattering cross section 

follows a power law for at least |Q|< 0.012 Å-1 and fits to

the data for each temperature yield the expected slope of 

−4 for the Porod law. Hence, this scattering results from

structures much larger than d = 2p /|Q| ≈ 100 Å, and the

Porod amplitude versus temperature (Fig. 1d) is similar to 

data in Fig. 1a and 1b, being constant at high temperatures 

but abruptly increasing with decreasing temperature 

below TSR. Polarized SANS measurements of the spin

flip cross section, S+− (inset to Fig. 1a) show a rise in S+−

1NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899

2University of Maryland, College Park, Maryland 20742

3Rutgers University, Piscataway, New Jersey 08854

FIGURE 1: (a) Temperature dependence of the normalized total 

counts. The inset shows the spin flip scattering cross section 

determined from the sum of the radially averaged polarized SANS 

data. (b) Temperature dependence of the average scattering cross 

section for Q = 0.0064 Å-1. (c) Semilog plot of the average scattering 

cross section at two temperatures. The lines are fits to the Porod 

law which has a ~ Q-4 dependence. (d) The Porod amplitude versus 

temperature as determined from the fits shown in (c). Lines are 

guides to the eye unless otherwise noted.
NCNR 2010 Accomplishments and Opportunities 9

below TSR, similar to the rises observed in Fig. 1a, b, and 

d, demonstrating that the abrupt increase in the scattering 

intensity below TSR indeed has a magnetic component. 

These data allow us to associate the observed increase 

in the Porod scattering below TSR (Fig. 1d) with a net 

magnetization developing within AFM domain walls.

To illustrate the experiment’s sensitivity to magnetic 

domains and domain walls, Fig. 2a shows the change in 

the SANS intensity I with increasing magnetic field, m0H, 

at various temperatures. We see that the initial slope of

I(m0H) increases as the temperature decreases, as is typical 

for field-induced scattering in magnetic systems, and that I

saturates above m0H ≈ 4 T at T = 4 K, similar to a canonical

magnetization versus field curve. The Porod amplitude as

a function of m0H (Fig. 2b) increases with increasing field

for m0H > 1 T until 4 T, similar to Fig. 2a. Since applying a 

magnetic field will first reorient the spins within magnetic

domains and then change the size/number of domains,

we associate these data with field induced changes to the

magnetic domain structure.

To determine the effect of an electric field on the scattering,

Fig. 2c shows the temperature dependence of the total 

normalized 2-D detector counts while applying E = 25

kV/cm, after either field cooling or zero-field cooling. In

the field cooled data, the counts increase with increasing

temperature until T ≈ TSR, while for the zero-field cooled

data they decrease. Above TSR subsequent changes in the 

total counts with increasing temperature are qualitatively 

similar to E = 0 data. The difference between the field

cooled and zero-field cooled data for T < TSR indicates that 

the electric field induces a different macroscopic ground

state, and that the induced ground state depends on the 

cooling protocol. The temperature dependence of field

cooled polarized SANS data is shown in Fig 2d, indicating

that the electric field affects the magnetic scattering in the

same temperature range as in Fig. 2c.

In the absence of a magnetic field, an ideal

antiferromagnetic possesses no net magnetization.

However, in HoMnO3 we have shown that the increase 

in low Q scattering with decreasing temperature below 

TSR = 40 K comes from magnetic structures (Fig. 1a inset)

and that this magnetic scattering is affected by an electric 

field (Fig. 2c and d). Using our interpretation of the data in

Fig. 2a and 2b, we postulate that the increase in magnetic 

scattering at low temperature for E = 0 and m0H = 0 in

Fig. 1 is due to the development of a net magnetization

within AFM domain walls. Thus, the increase in the Porod 

amplitude with decreasing temperature in Fig. 1d is due to 

either an increase in the contrast or in the number of AFM 

domain walls.

While AFM domains generally are not energetically

favorable, effects such as lattice strain, defects, grain 

boundaries, or in particular FE domains can cause their 

formation and lower the free energy. Furthermore, 

AFM domain walls can possess a net uncompensated 

magnetization, since they have lower symmetry than

the bulk material. Indeed, AFM domain walls have been 

observed in multiferroics [3], and pinning between FE 

and AFM domains in both YMnO3 and HoMnO3 has been 

observed [7]. Since applying a strong enough electric field

will alter the FE domains, we explain the change in the 

magnetic SANS intensity upon application of an electric 

field in terms of pinned FE and AFM domain walls.

Thus, when an electric field is applied, the change to the

FE domains adjusts the AFM domains pinned to them, 

causing a change in the magnetization stemming from

the AFM domain walls. Hence, our data indicate that the 

previously observed electric-field-induced magnetization

may originate from uncompensated spins in AFM domain 

walls, rather than conventional long range magnetic order. 

Nevertheless, the coupling of the electric field to magnetic

domain walls could prove useful in device applications.

References

[1] O. P. Vajk, M. Kenzelmann, J. W. Lynn, S. B. Kim, and S-W.

Cheong , Phys. Rev. Lett. 94, 087601 (2005).

[2] Th. Lottermoser, T. Lonkai, U. Amann, D. Hohlwein, J. 

Ihringer, and M. Fiebig, Nature 430, 541 (2004).

[3] B. Lorenz, A. P. Litvinchuk, M. M. Gospodinov, and C. W. Chu,

Phys. Rev. Lett. 92, 087204 (2004).

[4] S. Nandi, A. Kreyssig, L. Tan, J. W. Kim, J. Q. Yan, J. C. Lang, D.

Haskel, R. J. McQueeney, and A. I. Goldman, Phys. Rev. Lett. 100, 

217201 (2008).

[5] O. P. Vaijk and J. W. Lynn, private communication.

[6] B. G. Ueland, J. W. Lynn, M. Laver, Y. J. Choi, and S.-W.

Cheong Phys. Rev. Lett. 104, 147204 (2010).

[7] M. Fiebig, Th. Lottermoser, D. Fröhlich, A. V. Goltsev, and R. V. 

Pisarev, Nature 419, 818 (2002).

FIGURE 2: (a) Change in SANS intensity with an applied magnetic 

field at various temperatures. Data are shown after subtracting the 

zero-field data at each temperature. (b) The Porod amplitude versus 

magnetic field at T = 4 K. (c) Normalized total SANS intensity versus 

temperature for warming with E = 25 kV/cm applied, after either field 

cooling (squares) or zero-field cooling (circles). (d) Field cooled spin 

flip scattering cross section versus temperature for warming with E = 

25 kV/cm. Lines are guides to the eye.
10Condensed Matter

10

Frustrated magnetism and superconductivity in 

Fe1+ySe0.4Te0.6

V. Thampy1, J. A. Rodriguez2,3, Y. M. Qiu2,3, W. Bao4, T.J. Liu5, J. Hu5, B. Qian5, D. Fobes5, Z.Q. Mao5, 

and C. Broholm1,2

Awide range of metallic magnets develop superconductivity when magnetism is 

suppressed by pressure or chemical substitution. The 

discovery of iron superconductors offers new insight 

to this phenomenon and has reignited the search for 

higher temperature superconductors. In this quest, 

the new MACS spectrometer at NIST [1] has turned 

out to be an exciting new tool. 

Containing only square lattice iron layers, Fe1+ySe 

is arguably the simplest member of the new family. 

The exact role of chalcogen stoichiometry remains 

unclear, but a lattice distortion and modulated 

magnetism is found in Fe1+ySe1-xTex for x=0, and 

following a mixed regime for 0.1 < x < 0.3, bulk 

superconductivity occurs for x > 0.3 [2]. Figure 

1 shows momentum space maps of low energy 

magnetic neutron scattering in the normal (top) and 

superconducting (middle) state of Fe1+ySe0.4Te0.6. 

While itinerant magnets such as chromium have

sharp peaks from Fermi surface nesting, the red 

and yellow regions of intense scattering at 1 meV 

in Fig. 1a show that spin fluctuations in FeSe0.4Te0.6

cover a large fraction of the Brillouin zone. Such

fluctuations indicate magnetic ambivalence as in

frustrated magnets with a macroscopic ensemble of 

near degenerate states. At higher energies (6 meV, 

Fig. 1b) a doubly peaked maximum close to (0.5,0.5,0) 

indicates incommensurate correlations from Fermi 

surface nesting or competing exchange interactions. 

The connection to superconductivity is apparent 

from the suppression of low energy fluctuations

in the superconducting state (see Fig. 1c and 1e). 

Magnetic neutron scattering satisfies a sum-rule

which ensures the total cross section remains 

unchanged as spectral weight is redistributed in Q-ω

space. Our experiments show different destinations 

for normal state scattering as superconductivity 

develops. 

Figure 1f shows enhancement of magnetic scattering at ħω

= 6 meV for elliptical regions associated with Q = (0.5,0.5,0)

nesting of electron and hole pockets of the Fermi surface. 

A staple of magnetic superconductors, the corresponding 

spectroscopic resonance in Fe1+ySe0.4Te0.6 is evidence the 

(s+−) superconducting gap function has opposite signs on

the nesting electron and hole Fermi surfaces [3]. 

The comprehensive mapping capabilities of MACS also 

reveal elastic magnetic scattering close to Q = (0.5,0,0)

at low temperatures. The unusually broad peaks there 

indicate that interstitial sites might be seeding magnetic 

oscillations of the Fe1+yTe variety [4], which link up at 

low temperatures to form a spin glass. While the (1/2,0,0)

point corresponds to socalled double stripes where third 

nearest neighbor antiferromagnetic interactions are 

satisfied, the (1/2,1/2,0) point corresponds to satisfied

1Johns Hopkins University, Baltimore, MD 21218, USA

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

3University of Maryland, College Park, MD 20740

4Renmin University of China, Beijing 100872, China

5Tulane University, New Orleans, Louisiana 70118

FIGURE 1: 

Images of 

inelastic neutron 

scattering at 

1 meV (left 

column) and 

6 meV (right 

column) in the 

normal state (T = 

25 K) and in the 

superconducting 

state (T = 1.4 K) 

of Fe1+ySe0.4Te0.6. 

The bottom 

two frames 

(e-f) show 

the difference 

between 

superconducting 

and normal 

state data. 

The color bar 

indicates counts 

per minute. 

Temperature 

insensitive 

features result 

from Bragg 

feedthrough 

and/or phonons. 
NCNR 2010 Accomplishments and Opportunities 11

second nearest neighbor interactions. In both cases 

near neighbor correlations are mixed; both ferro and

antiferromagnetic. The variety of magnetic correlations 

indicates a strongly fluctuating spin system, which lacks a

leading magnetic instability; a desirable situation evidently, 

for superconductivity. 

Figure 2 distinguishes and details the temperature 

dependence of distinct parts of low energy magnetism in 

Fe1+ySe0.4Te0.6. While the suppression of inelastic scattering

near Q = (0.5,0.5,0) occurs with a characteristic temperature

FIGURE 2: (a) and (b) are images of elastic and inelastic (1.5 meV) 

neutron scattering in Fe1+ySexTe1-x. The yellow dashed lines show 

the regions where temperature dependent magnetic scattering is 

probed versus temperature in (b) and (d). The dashed line in (b) and 

(d) indicates the superconducting Tc determined by susceptibility 

measurements. 

close to the superconducting critical temperature, Tc

(dashed line), the elastic scattering at Q = (0.5,0,0)

shows no such anomaly. This provides an interesting 

link to the copper oxides where a spin glass unfazed by

superconductivity was also found in under-doped YBCO 

[5]. More specific information about the spin glass order

is obtained by analyzing cuts extracted from complete

maps of the difference between low and high temperature 

elastic scattering in the (hk0) and (h0l) planes. Figure 3a 

shows that the in-plane correlation length is just 2.6 (1) Å,

and of the same order as the lattice parameter. The out of 

plane correlations are accounted for by near neighbor Ising 

spin correlations with spins oriented along the tetragonal 

c-axis (Fig. 3b). There is a satisfying consistency here in 

that a spin glass is plausible in two dimensions only for 

Ising spins. It is also pleasing to see that high quality 

quantitative information can be extracted from the colorful 

maps of scattering produced by MACS. The relation of 

the spin glass to superconductivity is however, far from 

clear. Possible scenarios include phase separation into Te 

and Se rich regions with spin glass like magnetism and 

superconductivity respectively. A homogeneous multicritical state with spin glass and superconducting phases 

decoupled by segregation in momentum space is also 

possible. Further experiments including detailed electron 

microscopy will be needed to distinguish. 

Whether homogeneous or heterogeneous, the close

proximity of superconductivity and magnetism in 

Fe1+ySexTe1-x and the strong coupling to magnetic 

fluctuations with a wave vector that connects electron and

hole pockets of the Fermi surface, indicate a central role for 

magnetic fluctuations in promoting superconductivity. In

non-metallic frustrated magnets lattice strain can develop 

spontaneously to relieve magnetic frustration [6]. Fig. 1a 

indicates that magnetic frustration also occurs in metallic 

Fe1+ySexTe1-x. However, rather than a lattice distortion, 

superconductivity may in this case be needed to relieve 

frustration and lower the energy of the interacting spin 

system.

FIGURE 3: cuts extracted from complete maps of elastic difference 

intensity (1.4 K data minus 25 K data) in the (hk0) and (h0l) reciprocal 

lattice planes. The line in (a) is a Gaussian indicating an in-plane 

2.6(1) Å correlation length. The line in (b) is the calculated intensity for 

nearest neighbor only correlations of c-axis spin components. 

As these and other explanations are explored to further our 

understanding and control of magnetic superconductors, 

the unique mapping capabilities of MACS will be a key tool 

for new insight. 

References

[1] C. Broholm, Nucl. Instr. and Meth. in Physics Res. , A 369, 169 

(1996); J. A. Rodriguez et al., Measurement Science & Technology, 

19, 034023 (2008).

[2] T. J. Liu, et al., Nature Materials, 9, 716 (2010).

[3] Y. M. Qiu et al., Phys. Rev. Lett., 103, 067008 (2009).

[4] W. Bao W, et al., Phys. Rev. Lett., 102, 247001 (2009).

[5] C. Stock et al., Phys. Rev., B 73, 100504(R) (2006).

[6] S.-H. Lee, et al., Phys. Rev. Lett., 84, 3718 (2000).
12Condensed Matter

12

Lattice distortion and magnetic quantum phase 

transition in CeFeAs1-xPxO

C. de la Cruz1,2, W. Z. Hu3, S. Li2,3, Q. Huang4, J. Lynn4, M. Green4, G. F. Chen3,5, N. L. Wang3, H. 

Mook1, Q. Si6, P. Dai2,1,3

Since the initial discovery of superconductivity in the oxypnictide LaFeAsO in 2008, several 

other families of the Fe-based materials have 

been studied. The discovery of ubiquitous 

antiferromagnetic (AFM) order in the parent 

compounds of iron arsenide superconductors has 

renewed interest in understanding the interplay 

between magnetism and high-transition temperature 

(high-Tc) superconductivity in these and related 

superconducting materials [1]. Superconductivity 

in the Fe-based arsenides can be induced either via 

charge carrier doping or application of pressure to 

their semimetal parent compounds. Similar to the 

considerations made for the copper oxides, these 

properties make it possible that superconductivity 

is being influenced by a magnetic quantum critical

point (QCP) located in the not-yet accessed part

of the overall phase diagram. The tunability of 

quantum fluctuations in these compounds, leading

to a quantum phase transition, has been theorized

as a result of the unusual property of the parent 

compound as an incipient Mott insulator, and 

consequently being located near the boundary of 

itinerancy and localization [2]. To understand how

the AFM ground state itself can be suppressed 

by quantum fluctuations, it is important to

isoelectronically tune the crystal lattice structure 

to avoid the influence of charge carrier doping and

superconductivity. We have used neutron scattering

to show that replacing the larger arsenic with 

smaller phosphorus in CeFeAs1-xPxO simultaneously 

suppresses the AFM order and orthorhombic 

distortion near x = 0.4, providing the first evidence

for a magnetic quantum critical point in these 

materials. Furthermore, we find that the pnictogen

height in iron arsenide is an important controlling 

parameter for their electronic and magnetic 

properties, and also may play an important role in 

the electron pairing and superconductivity [3].

FIGURE 1: Experimentally obtained structural (TSR) and magnetic 

phase transition temperatures (TN(Fe) for the onset of Fe AMF order) 

as a function of P substitution for As, indicating the presence of a 

quantum critical point at x ≈ 0.4. The inset shows the dependence of 

the Fe long range ordered moment on the pnictogen height (As(z)), 

suggesting it plays an important role in tuning the electronic and 

magnetic correlations in the system.

In the undoped state, the parent compounds of the 

iron arsenide superconductors have an orthorhombic 

lattice distortion and collinear AFM structure. 

Applying a magnetic field to suppress the influence

of superconductivity is a common means to unmask 

any potential quantum critical point, but this approach 

is difficult to implement here because of the large

superconducting critical field for the iron pnictides

(a valuable property for applications, however). We

instead achieve the same result by using an isoelectronic 

phosphorus substitution for arsenic in CeFeAsO, 

recognizing that superconductivity appears neither in

CeFeAsO nor in CeFePO, a paramagnet with a tetragonal 

structure. Our systematic neutron scattering studies 

of the structural and magnetic phase transitions in 

CeFeAs1-xPxO demonstrate that the pnictogen height [the 

average Fe-As(P) distance] and orthorhombicity of the 

FeAs(P) tetrahedron critically control the iron AFM ordered 

moment and Néel temperature of the system. These 

results expose a magnetic quantum critical point, thereby 

1Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA 2The University of Tennessee, Knoxville, Tennessee 37996-1200, USA 

3Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

4NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6012 USA

5Renmin University of China, Beijing 100872, China

6Rice University, Houston, TX 77005, USA
NCNR 2010 Accomplishments and Opportunities 13

suggesting the importance of collective magnetic quantum 

fluctuations for both the electronic properties in the normal

state and the origin of superconductivity.

The parent compound CeFeAsO undergoes the tetragonal 

(space group P4/nmm) to orthorhombic (space group 

Cmma) structural transition below ≈ 158 K followed by

a long range commensurate AFM order with a collinear 

spin structure below ≈ 135 K. Similar to electron doping

of CeFeAsO via fluorine substitution of oxygen, we find

that phosphorus replacement of arsenic in CeFeAsO also 

results in decreasing both the structural and magnetic 

phase transition temperatures, despite having no charge 

carriers doped into the FeAs layer. The ordered Fe moment 

was also observed to smoothly decrease with increasing 

P content and tracked the distortion, vanishing at x ≈ 0.4,

suggesting the presence of a lattice-distortion-induced 

magnetic quantum phase transition through phosphorus 

doping. In addition, our demonstration of the pnictogen 

height as a parameter to systematically tune the electronic 

and magnetic properties of CeFeAs1-xPxO provides new 

insight that is likely of broad relevance to all families of the 

iron pnictides. In principle, the changing pnictogen height 

can affect both the superconducting gap function and the 

strength of the electron pairing.

For a complete determination of the phosphorus doping 

evolution of the low temperature crystal structure, the 

high resolution full powder diffraction patterns at low 

temperatures were obtained from the BT-1 neutron powder 

diffractometer. The outcome of the detailed Rietveld 

analysis, displayed in Fig. 2, shows the P-doping effect on 

the crystal structure of CeFeAs1-xPxO. Substitution of the 

smaller P ion on the arsenic site reduces all three lattice 

parameters with the system becoming tetragonal for x

> 0.37. The decreased c-axis lattice constant is achieved 

via a reduction of the As(P)-Fe-As(P) block distance 

[through reducing the FeAs(P) height], while the CeAs(P) 

and CeO block distances remain essentially unchanged 

with increasing P-doping. Remarkably, these trends are 

completely different from that of CeFeAsO1-xFx, where the 

c-axis lattice contraction is achieved via a large reduction 

of the Ce-As distance, while the Ce-O/F and As-Fe-As 

block distances actually increase with increasing F-doping. 

These fundamental differences reflect the fact that adding

electrons into the system via F-doping brings the Ce-O/F 

charge transfer layer closer to the superconducting As-FeAs block and facilitates electron transfer, while P-doping 

is a pure geometrical lattice effect without charge carrier 

transfer. Furthermore, since the Fe-As distance decreases 

rapidly with increasing P-doping which saturates at 

≈ 2.36 Å for CeFeAs1-xPxO, the reduced Fe-As(P) distance 

may induce strong hybridization between the Fe 3d and

the As 4p orbitals and thus quench the ordered Fe magnetic 

moment in CeFeAsO. More generally, the P-doping 

increases the electronic kinetic energy thereby weakening 

the magnetic order.

FIGURE 2: Low temperature structural evolution of CeFeAs1-xPxO as a 

function of P -concentration obtained from analysis of BT-1 data. The 

effect of the smaller P substitution to the larger As is to contract the 

Fe-As-Fe block and reduce the average Fe-As distance, while keeping 

the O-Ce-O block size essentially constant. This implies an increase in 

the Fe-As hybridization which in turn directly influences the Fe spin 

interaction. 

In summary, we have mapped out the structural and 

magnetic phase transitions of CeFeAs1-xPxO. We showed

that superconductivity does not appear in the magnetic 

phase diagram over the entire measured doping and 

temperature ranges, and found the surprising property 

that the lattice distortion and the static Fe AF order 

are gradually suppressed by isoelectronic phosphorus 

substitution of arsenic. These results indicate the presence 

of a magnetic quantum critical point near phosphorus 

concentration of x ≈ 0.4, thereby establishing that the

phosphorous substitution for arsenic in this class of 

materials is an ideal tuning parameter to explore the 

magnetic quantum critical behavior of the iron pnictides.

References

[1] J. W. Lynn and P. Dai, Physica C 469, 469 (2009).

[2] J. Dai, Q. Si, J-X. Zhu and E. Abrahams, Proc. Natl. Acad. Sci.

U.S.A. 106, 4118 (2009).

[3] C. de la Cruz, W. Z. Hu, S. Li, Q. Huang, J. W. Lynn, M. A.

Green, G. F. Chen, N. L. Wang, H. A. Mook, Q. Si, and P. Dai,

Phys. Rev. Lett. 104, 017204 (2010).
14Condensed Matter

14

Tuning the magnetic and structural properties 

of Fe1+xTe

E. E. Rodriguez1, P. Zavalij2, P.-Y. Hsieh1,2 and M. A. Green1,2

Precise control of chemical composition is proving to be as important in understanding 

the structural and electronic properties of the new 

iron based high temperature superconductors as it 

was for cuprates. In both cases, neutron diffraction 

has played a pivotal role in characterizing the

evolution of their structural and magnetic phase 

diagrams. We have recently shown that by reacting

iron telluride, a parent material to the new ironbased superconductors, with iodine vapor at low 

temperatures, the amount of excess iron in the crystal 

lattice (i.e., the x in the chemical formula Fe1+xTe) 

can be tuned, thus modifying both the magnetic 

ordering and the nature of the crystallographic 

phase transition at low temperatures [1]. This 

deintercalation process, or removal of the interstitial 

iron, leaves the central FeTe framework intact, thus 

allowing access to new Fe1+xTe compositions. It is 

an example of a “soft chemistry” approach, which 

is illustrated in the schematic of Fig. 1, and can be 

equally applied to single crystal as well as powdered 

samples.

Since the discovery of superconductivity in 

LaO1-xFxFeAs at a critical temperature of 26 K [2], 

this phenomenon has been revealed in several 

structural families that possess two-dimensional 

layers of (FeAs)− separated by positively charged 

ions (e.g., Ba2+). In contrast to these strong ionic 

solids, the simple compounds of FeCh, where Ch =

sulfur, selenium, or tellurium, possess layers that 

are only held together by relatively weak van der 

Waals forces. Nevertheless, the phase diagrams of

both systems universally exhibit a close proximity 

between superconductivity and an ordered magnetic 

regime, the border between the two being controlled 

by chemical composition or externally applied 

pressure. The FeCh system has been shown to be 

particularly sensitive to stoichiometry. For example, 

b-Fe1.01Se is superconducting at temperatures below 

8.5 K, whereas b-Fe1.03Se is neither magnetic nor 

superconducting, demonstrating that the excess 

interstitial iron is detrimental to the superconducting 

properties [3].

Fe1+xTe has only been reported for 0.067 < x < 0.17, with the 

excess interstitial iron located between the layers composed 

of edge-sharing FeTe4 tetrahedral units (See Fig. 1). The 

amount of interstitial Fe controls the material’s structure 

and magnetism. At low temperature for x < 0.11 the crystal 

lattice is orthorhombic and has magnetic ordering that is 

commensurate with the iron lattice; for materials at higher 

values of interstitial iron (x > 0.11), the lattice is monoclinic 

and has an incommensurate magnetic ordering. Fe1+xTe 

becomes superconducting upon substitution of selenium 

or sulfur for tellurium, but this substitution also affects 

the iron stoichiometry. Thus, studying how these two 

parameters contribute to changes in the properties of these 

materials remains unknown. To better illuminate these 

issues, the ability to exactly control the composition is 

essential.

A comparison of neutron powder diffraction patterns for 

the I2-reacted and unreacted samples revealed significant

differences in relative intensities of Bragg reflections

between the two. In particular, accurate determination 

of the iron content was due to the large coherent neutron 

scattering length of 9.45 fm for iron. Least-squares 

refinement of the neutron diffraction data gave a crystal

structure of the unreacted sample with a composition 

of Fe1.118(5)Te, compared to Fe1.042(5)Te for a sample 

deintercalated by iodine. 

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

2University of Maryland, College Park, MD 20742

FIGURE 1: Schematic diagram illustrating how iodine molecules react 

with the iron atom interstitials, which are displayed as the partially 

occupied white atoms between the orange FeTe4 tetrahedra. The 

presumed side product, FeI2, was washed from the deintercalated 

Fe1.04Te with methanol as the solvent. 
NCNR 2010 Accomplishments and Opportunities 15

Figure 2 shows the neutron diffraction patterns, observed 

and calculated, for the Fe1.042(5)Te sample. In all samples, 

the refinement yielded atomic sites within the FeTe4

tetrahedra at full occupancy, suggesting that the I2 was 

preferentially removing iron from the interstitial site only. 

Further inspection of the structural parameters revealed 

that the deintercalation of the powders is associated with a 

small expansion of the tetragonal crystal lattice in both the 

a and c directions, implying that the interstitial Fe bonding, 

within and between the layers, has the effect of drawing 

the lattice together. 

The structural changes upon iron extraction resulted in 

interatomic distances between the iron atoms increasing 

while the Fe−Te bond distance actually decreased.

Likewise, the variance of the Te−Fe−Te tetrahedral angles

also decreased. Here, bond angle variance is an average 

of the differences of the FeTe4 tetrahedral bond angles 

from the ideal 109.5o, a value that has been shown to be 

correlated with the superconducting critical temperature 

[5]. 

Figure 3 shows a comparison of part of the neutron 

data for unreacted and I2-reacted powder samples at 

base temperature and 100 K as well as the effect of the 

reaction on the surface of single crystal samples. Figure 

3 demonstrates that at low temperatures, the unreacted 

sample has an incommensurate magnetic propagation 

vector and is orthorhombic, whereas the I2-reaction sample 

has a commensurate propagation vector and is monoclinic. 

These observations are consistent with the change in 

stoichiometry. 

In summary, we have demonstrated that the amount of 

interstitial iron in the layered structure of Fe1+xTe can be 

diminished by reaction with iodine. It has previously 

been reported that substitution of Te with Se or S to 

produce superconductivity has two effects. First, there 

is suppression of the low temperature structural and 

magnetic phase transitions. Second, there is a reduction 

of the interstitial iron content such that the optimal 

superconducting composition FeTe0.5Se0.5 has little or no 

excess iron [6]. The capability of controlling iron content 

through our technique will allow for the investigation 

of larger regions of the superconducting Fe1+x(S,Se,Te) 

phase diagrams, as well as allow for the two factors upon 

substitution to be controlled and evaluated independently. 

References

[1]. E. E. Rodriguez, P. Zavalij, P. –Y. Hsieh, M. A. Green, J. Am.

Chem. Soc., DOI: 10.1021/ja104004t (in press).

[2]. Y. Kamihara, T. Watanabe, M. Hirano, H. Hosono, J. Am.

Chem. Soc., 130, 3296 (2008).

[3]. T. M. McQueen, Q. Huang, V. Ksenofontov, C. Felser, Q.

Xu, H. Zandbergen, Y. S. Hor, J. Allred, A. J. Williams, D. Qu, J.

Checkelsky, N. P. Ong, R. J. Cava, Phys. Rev. B 79, 014522 (2009).

[4]. 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, Z. Q. Mao, Phys. Rev.

Lett. 102, 247001 (2009).

[5]. C. de la Cruz, Q. Huang, J. W. Lynn, J. Y. Li, W. Ratcliff, J. L.

Zarestky, H. A. Mook, G. F. Chen, J. L. Luo, N. L. Wang, P. C. Dai,

Nature 453, 899 (2008).

[6]. B. C. Sales, A. S. Sefat, M. A. McGuire, R. Y. Jin, D. Mandrus, Y. 

Mozharivskyj, Phys. Rev. B 79, 094521, (2009).

FIGURE 2: Observed (red), calculated (blue) and difference (purple) 

intensity of the neutron powder diffraction patterns of Fe1.04Te. Data 

were obtained from the BT-1 instrument using the Cu311 monochromator (l = 1.540 Å). The residual of the fit was Rwp = 6.7 % and the 

c2 = 1.367. 

FIGURE 3: Magnetic and structural transitions for the unreacted 

Fe1.118(5)Te and I2-reacted Fe1.051(5)Te compounds. On far left, the low 

2q scattering is due to the magnetic ordering at base temperatures. 

Splitting of the (112) Bragg peak is also shown for the I2-reacted 

sample. On far right, SEM photographs of the surfaces of unreacted 

single crystal and I2-reacted single crystal.
16Biology

16

Neutron reflectometry study of the conformation of 

HIV Nef bound to lipid membranes

M. S. Kent1, J. K. Murton1, D. Y. Sasaki1, S. Satija2, B. Akgun2, H. Nanda2, F. Heinrich2,3, J. E. Curtis2, 

J. Majewski4, C. R. Morgan5 and J. R. Engen5

Aparticularly challenging problem in structural biology is to characterize changes in protein

structure that result upon interaction with a lipid 

membrane. Neutron reflectometry (NR) can resolve

structural details of membrane-associated proteins 

in physiological conditions, and may be unique 

in its ability to directly resolve details of the full 

membrane-bound protein structure. For a protein 

bound to a planar lipid membrane, NR determines 

the in-plane averaged distribution of amino acid 

residues normal to the membrane, and is sensitive 

to any changes in that distribution. In the work 

highlighted here NR was used to resolve the first

details of the conformation of Nef from HIV upon 

binding to lipid membranes [1]. Nef is an HIV1 accessory protein that directly contributes to 

AIDS progression and its effects only occur when 

it associates with membranes [2]. It is believed to 

undergo a transition from a solution conformation 

to a membrane-associated conformation that enables 

it to interact with cellular proteins. Despite its 

medical relevance, there is no direct information 

about the conformation of membrane-bound 

Nef. Understanding how the membrane-bound 

conformations of Nef relate to its ability to bind to 

cellular proteins under different conditions could 

lead to drug therapies to counteract its harmful 

effects.

Naturally occurring Nef has an amine-terminated 

arm (N-terminus) which is myristoylated (myr). 

Purified deuterated myr-Nef was not available

for this study. Therefore a Histidine (6xHis) tag 

on the N-terminus was used to bind full-length, 

unmyristoylated deuterated Nef to a planar lipid 

membrane (in this case, a Langmuir monolayer). 

The monolayer was composed of mixtures of 

dipalmitoylphosphatidylcholine (DPPC) and 

1,2-distearylglycero-3-triethyleneoxideiminodiacetic 

acid (DSIDA). The N-terminal 6xHis tag on d-Nef was 

spatially located where the naturally occuring myristic 

acid moiety would be found in Nef. The His tag adsorbed 

to Cu2+ in the headgroups of DSIDA to localize Nef to the

membrane. This system represents one of the possible 

limiting states of membrane-bound myr-Nef, namely the 

open form in which the N-terminus is unassociated with 

the core domain but associates specifically with lipid

membranes. The experimental system is illustrated in Fig. 

1, which shows the two size extremes of Nef and their

relationship to the membrane and the neutron beam. For 

the most extended form, the dimensions of Nef from the 

model of Geyer and Peterlin [3] were used and the protein 

was attached to the membrane by its N-terminus with no 

insertion. Figure 1 also shows the dimensions of the two 

lipids and a very highly compact form of Nef.

1Sandia National Laboratories, Albuquerque, NM 87123

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

3Carnegie Mellon University, Pittsburgh, PA 15213

4Los Alamos National Laboratories, Los Alamos, NM 87545

5Northeastern University, Boston, MA 02115

FIGURE 1: Illustration of the experimental system. Neutrons strike the 

opposite face of the lipid monolayer from where Nef interacts. The 

dimensions of Nef from the most extended form of the Geyer and 

Peterlin model [3] are shown at the left, along with the dimensions 

of the two lipids. For the purpose of size comparison, a model of 

a highly compact form of Nef is shown on the right. This figure is 

meant to be illustrative of the experimental setup and not necessarily 

to show the true conformations of Nef at the membrane. 
NCNR 2010 Accomplishments and Opportunities 17

Fig. 2a shows reflectivity data collected after allowing

d-Nef to adsorb to a monolayer of 65 % d-DSIDA/Cu2+

35 % d-DPPC for 2.0 h from solution at 0.5 μmol/L, and 

then flushing the subphase with 50 ml of Tris buffer. The

reflectivity data were collected over a period of 6 h after

subphase exchange. The profiles with uncertainty limits

from simultaneous fits to the data in Fig. 2a before and

after adsorption of d-Nef are shown in Fig. 2b. The profiles

for the lipids alone are denoted by a blue/pink/yellow 

color scheme, and the profiles with d-Nef are denoted by a

black/red/yellow color scheme. The model-independent 

profile of d-Nef is comprised of a ≈ 40 Å layer dense in

residues that is directly adjacent to the lipid headgroups 

followed by a very slight tail extending into the subphase. 

The dense layer is asymmetric with the maximum skewed 

toward the membrane. Conformations in which the core 

domain is significantly displaced from the membrane such

as depicted on the left in Fig. 1 can be ruled out. Certain 

protein binding sites on Nef appear to be blocked in this 

conformation, including a polyproline-rich segment on 

the core domain that is known to be a binding site for SH3 

domains of tyrosine kinases [2]. Indeed, no binding of 

d-SH3 was detected upon introducing it into the subphase 

at 1.5 μmol/L.

The profiles also show that the SLD of the lipid headgroup

region increases upon adsorption due to the insertion of 

d-Nef residues into the lipid headgroups. This is consistent 

with the fact that, for the present conditions, adsorption of 

the d-Nef containing monolayers is always accompanied by 

an increase in the area per molecule of ≈ 5 %. An example is

shown in Fig. 3. The increase in area per molecule observed 

upon membrane binding of 6xHis Nef through the His 

tag provides direct evidence of insertion of residues. Prior 

work by others involving mutants of Nef has demonstrated 

that Nef interacts with membranes through the N-terminus 

and also with residues on the N-terminal arm that are able 

to form an amphiphilic helix [4]. We conclude that insertion

of a portion of the N-terminal arm positions the core 

domain directly against the lipid headgroups. 

This work provides the first structural data for

membrane-associated Nef. Both good resolution and 

a strong neutron scattering signal were achieved with 

the use of deuterated lipids and d-Nef against an H2O 

subphase. The reflectivity data and area per molecule data

both indicated insertion of residues into the membrane 

upon binding through the N-terminal His tag. When

interpreted in light of the results of prior studies, this 

strongly suggests that a portion of the N-terminal arm 

inserts into the membrane. Binding of Nef to the same 

membrane also occurred at a much lower level in absence 

of the interaction through the His tag, however, in that case 

no insertion of residues into the membrane was detected. 

We conclude that binding through the N-terminus

contributes to N-terminal arm insertion. Upon insertion of 

a portion of the N-terminal arm, the core domain of Nef is 

located directly against the lipid headgroups and forms a 

layer approximately 40 Å thick. The binding site for SH3

domains appears to be inaccessible in this conformation. In 

the future, further studies will focus on the conformation 

of membrane-bound Nef under different conditions and its 

ability to bind to a variety of other cellular proteins.

References

[1] M.S. Kent, J. K. Murton, D. Y. Sasaki, S. Satija, B. Akgun, H. 

Nanda, J. E. Curtis, J. Majewski, C. R. Morgan, and J. R. Engen, 

Biophysical Journal (submitted).

[2] S. T.Arold, and A. S. Baur, Trends Biochem Sci 26, 356 (2001).

[3] M. Geyer, and B. M. Peterlin, FEBS Lett 496, 91 (2001).

[4] H. Gerlach, V. Laumann, S. Martens, C. F. W. Becker, R. S.

Goody, and M. Geyer, Nature Chemical Biology 6,46 (2009).

[5] F. Heinrich, T. Ng, D. J. Vanderah, P. Shekhar, M. Mihailescu, 

H. Nanda, and M. Losche, Langmuir 25 4219 (2009). 

FIGURE 2: a) NR data for the d-DPPC/h-DSIDA monolayer alone (l) 

and with bound d-Nef (n) adsorbed. Adsorption was arrested after 

2.0 h. b) SLD profiles corresponding to the data in (a) (with 

uncertainty limits determined from a Monte Carlo resampling 

procedure [5]). The lipid tail profile (large peak) continues into the 

blue/pink region for the monolayer alone. Adsorption of d-Nef gives 

rise to a second peak adjacent to the DSIDA headgroups.

FIGURE 3: Change in area per molecule upon adsorption of 6xHis 

d-Nef to a monolayer of 35 % DPPC, 65 % DSIDA/Cu2+. Time t = 0 

corresponds to the first detection of absorption in the reflectivity 

data. 
18Biology

18

How does the stiffness of lipid vesicles change 

as they interact with pore-forming peptides?

J.-H. Lee1, S.-M. Choi1, C. Doe1, A. Faraone2,3, S. R. Kline3, P. A. Pincus4,1

Cell membranes, which consist of lipid bilayers, play important roles in cells as walls to maintain 

intracellular fluid concentrations and as matrices to

host membrane proteins. During cellular processes 

such as the releasing and absorption of vesicles, cell 

fission and cell fusion, the cell membranes undergo

various morphological changes governed by the 

interplay between proteins and lipid membranes. 

Yet, just how membrane elastic properties are 

affected by protein-lipid interactions remains only 

partially understood. Antimicrobial peptides are 

one of the most common examples of proteins 

that modify membrane morphology. A typical 

antimicrobial peptide consists of 20 to 40 amino 

acids with a length comparable to the lipid bilayer 

thickness. Depending on the peptide to lipid molar 

ratio, P/L, the peptides associate with the membrane 

in two distinct ways (Fig. 1(a)). When P/L is low, the 

peptides insert into the headgroup region (depicted 

as purple bars lying horzontally on the membrane

surface) and cause thinning of the chain region, 

creating an internal membrane tension. Upon 

reaching a critical value of P/L (P/L*), the peptides 

start to perforate, forming trans-membrane pores to 

relieve the internal membrane tension [1]. While the

pore-forming mechanisms of antimicrobial peptides 

in lipid membranes have been widely investigated, 

the effects of pore formation on the membrane 

fluctuation and corresponding elastic properties have

not yet been reported. 

In the study highlighted here [2], the thermal fluctuation

and elasticity of dioleoyl-phosphocholine (DOPC) large 

unilamellar vesicle (LUV) membranes interacting with 

antimicrobial peptides (melittins) were investigated using 

neutron spin-echo spectroscopy (NSE). Melittin is known 

to form toroidal pores in a DOPC bilayer. Suspensions 

of 6 mmol/L DOPC LUV in D2O buffer with different 

concentrations of melittin were prepared. The ratios of 

31P-NMR signals of the suspensions with and without 

adding relaxation agent indicate that P/L*, defined as P/L at 

which the half of LUVs are perforated, is ≈ 0.4 % (Fig. 1(b)).

The normalized intermediate dynamic structure factor,

I(q,t)/I(q,0), of the DOPC LUV/melittin in D2O buffer 

at different values of P/L was measured at 30 °C using 

neutron spin echo (NSE) spectroscopy, where q is the 

magnitude of scattering vector and t is the Fourier time. 

Measured I(q,t)/I(q,0) values were analyzed using the

extended Zilman-Granek model [3,4] which describes

the single membrane dynamics including the effects of 

internal dissipation within the membrane. If qR >> 1, 

where R is the radius of the LUV, I(q,t)/I(q,0) of a 

thermally fluctuating bilayer membrane is expressed as

I(q,t)/I(q,0) = exp[–(Γ(q)t)

2/3] where the relaxation rate Γ(q) 

is given as Γ(q) = 0.025g(kBT/k)

1/2(kBT/h)q3. Here, k is an 

effective bending modulus of membrane, γ is a function of 

kBT and approaches unity for large bending modulus, kB

is the Boltzmann constant, T is the absolute temperature, 

and η is the viscosity of the solvent. At the length and time 

scales relevant to NSE measurements, k has contributions 

from the bending modulusof the membrane and from the 

internal dissipation within the membrane expressed by the 

bilayer compressibility modulus k, i.e., k = k + kd2, where d

is the thickness of the undeformed bilayer (see Fig. 1a). It 

is known that κ and k of bilayers are coupled as κ = bh2k, 

where b is a constant prefactor and h is the thickness of the 

chain region (Fig. 1a). The measured values of I(q,t)/I(q,0) 

agree well with the extended ZG model, resulting in Γ(q) 

which follows the q3-dependence as expected by the model 

(Fig. 2).

1Korea Advanced Institute of Science and Technology, Daejeon, Korea, 305-701 2University of Maryland,, College Park, MD 20742

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

4University of California, Santa Barbara, CA 93106

FIGURE 1: (a) Schematics for bound melittin and pores in lipid 

membranes. (b) 31P NMR signal ratio (with/without Mn2+) of 

DOPC LUV/melittin vs. P/L.

~

~

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NCNR 2010 Accomplishments and Opportunities 19

FIGURE 2: (a) I(q,t)/I(q,0) of DOPC LUV/melittin at different values of 

q. The solid lines are fits using the extended ZG model. (b) Relaxation 

rate Γ(q) vs. q. The solid line is a fit using the expression for Γ(q) 

described in the text.

The effective bending moduli κ of DOPC/melittin 

membranes are determined by fitting the measured Γ(q) 

with the extended ZG model, from which the bending

modulus κ and the bilayer compressibility modulus are 

estimated (Fig. 3(a)). In region I where melittin is adsorbed 

horizontally on the membrane surface, both κ and k

decrease with P/L and reach a minimum around P/L*. In 

region II and III where melittin forms pores, and k increase 

slightly until P/L ≈ 1.7 % (region II) and increase rapidly 

from P/L ≈ 2.4 % (region III). Since the relative change of 

the chain region thickness with P/L is fairly small, it cannot 

explain the rather large change of measured elasticity. 

When a peptide is adsorbed between lipid headgroups,

perturbation of the chain packing occurs together 

with membrane thinning. A statistical thermodynamic 

analysis of chain packing in bilayers showed that could 

be dramatically decreased by the increase of chain 

conformational entropy in the membranes. Therefore, 

the decrease of κ (and k) in region I may be dominated by 

the perturbation of chain packing by peptide adsorption. 

Since melittin forms a rigid α-helix on a membrane, the 

pores formed by 4 to 7 melittins may be rather rigid and 

dominantly contribute to the increase of κ and k in region 

II. In region III, the rate of increase of κ and k with P/L

becomes much larger near P/L = 2 %. To explain this, the

inter-pore interaction needs to be considered because the 

population of pores is high in region III.

Theoretical and experimental studies indicate that the 

interaction between nearby inclusions in a membrane is 

mediated through the local perturbation of lipid chain 

packing near the inclusions. Therefore, when inclusions 

are far apart, the inter-inclusion interaction is zero or

negligibly small. However, when the two regions deformed 

by inclusions begin to overlap, a repulsive inter-inclusion 

interaction sets in. In the DOPC LUV/melittin system, 

there are two types of membrane regions deformed by a 

bound peptide (bound patch) and a peptide-induced pore 

(pore patch) (Fig. 3(b)). At P/L*, the average inter-bound 

melittin distance is calculated to be ≈ 100 Å which is 2

times larger than the contact distance of bound patches 

in DOPC bilayer (2rb = 50 Å). Therefore, the inter-patch

interaction in region I may be negligible. Above P/L*, the 

average inter-pore patch distances at P/L = 2 % and 4 % are

calculated to be ≈ 120 Å and ≈ 80 Å, respectively. Since the

contact distance of pore patches is 77 Å (2rp), the inter-pore 

interaction may be small or negligible in region II but it 

becomes appreciable in region III, especially near P/L =

4 %. It should be noted that k and k begin to increase 

rapidly from P/L ≈ 2 % where the inter-patch interaction is 

expected to become significant.

The thermal fluctuation and elasticity of DOPC LUV

membranes interacting with pore-forming peptides, 

melittins, has been investigated for the first time by in-situ

NSE measurements. The results of this study are expected 

to play an important role in understanding the elastic 

behavior and morphological changes of cell membranes 

induced by protein-membrane interactions,and may 

provide new insights for developing new theoretical 

models for membrane fluctuations which include the

membrane-mediated interactions between protein patches.

References

[1] H. W. Huang et al. Phys. Rev. Lett. 92, 198304 (2004).

[2] J.-H. Lee, S.-M. Choi, C. Doe, A. Faraone, P. A. Pincus, and S. R. 

Kline, Phys. Rev. Lett. 105, 038101 (2010). 

[3] A. G. Zilman and R. Granek, Phys. Rev. Lett. 77, 4788 (1996). 

[4] M. C. Watson and F. L. H. Brown, Biophys. J. 98, L9 (2010).

FIGURE 3: 

(a) Reduced 

relaxation rate 

G = G(q)h0/(kBTq3), 

bending modulus 

k and bilayer 

compressibility 

modulus k of 

DOPC/melittin 

in D2O buffer at 

different peptide/

lipid ratios, P/L. (b) 

Scaled schematics 

of the distributions 

of bound melittin 

and pores on the 

membrane at P/L = 

0.4 % (I), P/L = 

1.7 % (II) and P/L

= 4.0 % (III). In the 

DOPC bilayer, the 

bound patch radius 

rb is ≈ 25 Å and the 

pore radius rp is ≈ 

38.5 Å.

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20Biology

20

Bilayer membrane dynamics in 

NSAID-phospholipid adducts

M.B. Boggara1,4, A. Faraone2,3, R. Krishnamoorti4

The bending modulus (κ) of a lipid bilayer, a model for a cell membrane, is a key parameter in 

understanding its viscoelastic behavior and stability 

and a key determinant in a number of membrane 

processes. From a biophysical viewpoint, κ governs 

the thermal undulations that could determine 

short-range interactions between membranes and 

substrates. Most drug molecules interact with cell 

membranes to exert their therapeutic action. This 

is especially so in the case of amphiphilic drug 

molecules such as nonsteroidal anti-inflammatory

drugs (NSAIDs) [1]. Understanding the behavior of 

membrane κ is thus potentially useful in developing 

drug-bilayer adducts for applications such as 

targeted drug delivery. 

Here we highlight our study of κ as a function of 

pH in the physiologically relevant range of 2 to 8 

focusing on the effect of ibuprofen, a popular NSAID, 

on bilayers made of 1,2-dimyristoyl-sn-glycero-3-

phosphatidyl-choline (DMPC) [2]. Changing pH is 

likely to change the lipid-lipid, lipid-water and druglipid electrostatic interactions and the charge states 

of both protonated and deprotonated ibuprofen. 

Moreover, since such lipid–NSAID adducts have 

been suggested as a safer means of delivery of 

anti-inflammatory drugs [3], it is important to

understand the potential impact of changes in pH 

on the mechanical properties of the membranes and 

therefore long-term stability of such adducts. 

Neutron spin echo (NSE) is an excellent tool 

to directly probe the dynamics of lipid bilayer 

membranes by measuring the dynamics of heightheight correlations in the plane of the membrane 

which is related to the bilayer κ (Fig. 1). Although, 

intercalation of phospholipid bilayers by small 

molecules is expected to lead to significant changes

in the bilayer κ, these changes are known to be a 

complex interplay of many factors. Several studies 

have indicated that the drug-effect on the membrane 

mechanical properties can range from lowering κ, the 

elimination of micro/nano domains in mixed lipid 

bilayer systems, vesicle fusion, and influence on the drug’s

therapeutic or side effects. 

NSE connects the dynamics of height-height 

correlations to the intermediate structure factor, 

S(q,t) = I(q,t)/I(q,0) = Ae–(Gt)2/3, which is related to κ via the 

decay constant given by G = (0.025gkBT/h)(kBT/κ)

1/2 q3, 

according to Zilman and Granek [4]. The plots of S(q,t) at 

various q values in Fig. 2a are combined in the inset to 

Fig. 2a to give a master curve, ln[S(q,t)] vs. q2t2/3 by 

substituting for Γ in S(q,t), which is then used to determine 

κ. The factor γ = (1 – 3ln(qz) kBT/4πκ) is ≈ 1 for κ >> kBT

1Current Address: Rensselaer Polytechnic Institute, Troy, New York 12180.

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

3University of Maryland, College Park, Maryland 20742

4University of Houston, Houston, Texas 77204

FIGURE 1: Left: Small unilamellar lipid vesicles used for experiments. 

Middle: Fluctuations for pure lipid and drug-incorporated bilayers. 

Above right: bilayer physical parameters obtained using SANS. 

Below right: NSE-measured membrane fluctuations expressed as the 

height-height dynamic correlation function.

FIGURE 2: (a) Intermediate structure factor for DMPC at pH ≈ 7.4 and 

30  ̊C. The number next to each curve is the value of q in Å–1. The inset 

shows Zilman-Granek scaling to produce a master curve allowing the 

extraction of the membrane bending modulus, κ. (b) κ as a function 

of pH for DMPC and ibuprofen–DMPC (31 % mole fraction) at 30  ̊C 

(solid circles). Also shown are the data for pH ≈ 1.6 and 37  ̊C (open 

triangles). 
NCNR 2010 Accomplishments and Opportunities 21

which is valid for lipid bilayers. η is the solvent viscosity 

experienced by the bilayer and is usually taken as ≈ 3ηD2O

to capture the effect of the local aqueous environment 

on the viscous dissipation of membrane undulations, as 

validated by atomistic molecular dynamics simulations. 

The inferred bending modulus for the lipid bilayer as a 

function of pH with and without ibuprofen is shown in Fig. 

2b.

Figure 2b shows that at 30  ̊C the bending modulus of

DMPC membranes, κDMPC, decreases significantly at low

pH values while being roughly constant at high pH. On 

the other hand, κibuprofen-DMPC remains unchanged with 

varying pH and is lower than κDMPC. At a pH of ≈ 2 and

at 37  ̊C, above any gel to fluid transitions for the lipid,

the values of κ for the membranes with and without 

ibuprofen are roughly identical. The inferred κ values 

result from a combination of various deformation modes 

such as bending, area deformation, shear, thickness 

fluctuations, and molecular protrusion. The bilayer κ is 

further influenced by both the hydrophobic chains (via 

bilayer thickness) and the hydrophilic headgroup (via

surface charge density or area compressibility). Since the 

bilayer surface charge density, σ, changes with pH, our 

qualitative estimates suggest that the contribution due to 

the electrostatic component κel to κ is ≈ kBT at low pH and 

therefore insignificant. For pH > 4 κel is at least two orders 

of magnitude higher than at low pH, and potentially a 

significant fraction of κ. 

The bilayer thickness d impacts κ through κ ≈ KAd2/c, where 

KA is the area compressibility modulus and c ≈ 12 to 48.

For DMPC, κ decreases by ≈ 32 % with a pH change from

8 to 2 at 30  ̊C. Further, at a pH of ≈ 2, κ decreases by ≈ 18%

when the temperature is raised from 30 °C to 37 °C. Along 

with d decreasing from (4.7 ± 0.1) nm at 30  ̊C to (4.3 ± 0.1)

nm at 37  ̊C, this decrease in κ with temperature is due to 

the lipid chain undergoing a gel-like to fluid-like transition.

Moreover, the headgroup hydration is slightly lowered 

at low pH, suggesting that the decrease in κ with pH has 

origins in the structural and electrostatic perturbations 

to the headgroup. Addition of ibuprofen decreases κ by ≈

53 % at high pH, where the drug is anionic, and locates in 

the headgroup/chain interfacial region [5]. On the other 

hand, ibuprofen leaves κ almost unaffected at low pH when 

it is neutral and locates deeper in the chains. 

The effect of ibuprofen on κ can be understood by 

considering structural and hydration changes. Using κ

obtained from spin echo [2] and d ≈ 4.3 nm for DMPC in

fluid phase and ≈ 4 nm for ibuprofen–DMPC from SANS

[6], values of KA were estimated (Table 1). At low pH and 

high temperature, the decrease in headgroup hydration 

and protonation of phosphate in the headgroup in the case 

of DMPC, leads to a headgroup region with low σ. Thus 

the bilayer presents low resistance to undulations as well 

as changes in local area. In the case of ibuprofen–DMPC, 

as the drug partitions into already fluid-like chains, the

resulting KA is comparable to that of DMPC. Thus, the 

values of κDMPC and κibuprofen–DMPC are similar at pH ≈ 2. At

high pH, the headgroup is well hydrated and zwitterionic

for DMPC, resulting in higher values of KA. On the other 

hand, ibuprofen partitions into the headgroup region 

leading to a reduction in headgroup hydration. This results 

in a much smaller value of KA, nearly half that of DMPC as 

has been observed in SOPC lipid systems in the presence 

of drug-like salicylate or short-chain alcohols, and which 

needs direct experimental confirmation for ibuprofenDMPC system.

pH

DMPC Ibuprofen – DMPC

(mole ratio 0.31/1) 

κ/kBT KA(mN/m) κ/kBT KA(mN/m)

1.6 18.0 ± 0.5

(13.2 ± 0.3) 

163 ± 8 

(147 ± 8) 

12.2 ± 0.3 

(12.0 ± 0.2) 

153 ± 8 

(154 ± 7) 

3.3 24.6 ± 0.8 267 ± 15 

4.9 26.8 ± 0.9 291 ± 17 12.8 ± 0.3 161 ± 9 

7.4 26.2 ± 0.8 285 ± 16 12.3 ± 0.3 154 ± 8 

Table 1. Membrane bending (κ) and area compressibility (KA) 

modului as a function of pH at 30 °C (data in parenthesis 

correspond to T = 37 °C).

To summarize, using a combination of NSE along with

structural studies based on SANS and MD simulations, 

we have examined the changes in the bending modulus 

for DMPC-based membranes with pH and addition of 

ibuprofen. Significantly, we observe that κ decreases by 

≈ 40 % going from pH ≈ 8 to pH ≈ 2 and attribute the

decrease to changes in lipid interactions and headgroup 

hydration. Further, ibuprofen lowers κ at all pH values 

due to a combination of bilayer thinning, reduction in 

headgroup hydration and a lower area compression 

modulus. These studies provide a unified understanding of

the role of electrostatics and membrane additives in cellular 

membranes. As well as adding to understanding useful in 

creating lipid-based systems for targeted delivery of such 

NSAIDs to the sites of inflammation, this work further

signifies an important first step in an attempt to understand

at a molecular level how NSAIDs might be causing ulcers.

References

[1] H. Chakraborty, S. Mondal, M. Sarkar, Biophys. Chem. 28, 137 

(2008).

[2] M.B. Boggara, A. Faraone, R. Krishnamoorti, J. Phys. Chem. 

B 114, 8061 (2010). 

[3] L.M. Lichtenberger, J.J. Romero, W.M.J. de Ruijter, F. Behbod,

R. Darling, A.Q. Ashraf, S.K. Sanduja, J. Pharmacol. Exp. Ther.

279, 298 (2001).

[4] A.G. Zilman, R. Granek, Chem. Phys. 284, 195 (2002).

[5] M.B. Boggara, R. Krishnamoorti, Biophys. J. 98, 586 (2010).

[6] M.B. Boggara, R. Krishnamoorti, Langmuir 26, 5734 (2010). 
22Engineering

22

A method for the measurement of retained austenite 

content in steels

T. Gnäupel-Herold1,2, A. Creuziger3

With the recent emergence of transformation induced plasticity (TRIP) – with more than a 

century of development behind it – steel has seen 

a major developmental milestone bringing new 

levels of combined strength and ductility. Because of 

this, TRIP steels are seen as an important structural 

material for future car bodies. The key property 

responsible for this advance is the deformation 

induced transformation of the minority phase 

austenite (face centered cubic – fcc) into martensite 

(body centered tetragonal – bct), both embedded in 

the majority ferrite phase (body centered cubic – bcc). 

Therefore, the retained austenite (RA) content is 

intimately related to the strength, the formability and 

deformation history of TRIP steels. 

Considering the importance of this property it 

is astounding that the measurement of the RA 

content through diffraction – seen as both accurate 

and precise – is based at least in part on heuristic 

principles that have rarely been questioned. The 

principle in question is the presumed randomness 

of grain orientations or, rather, the lack thereof. This 

presumption is never justified because there is no

steel without some degree of preferred orientation. 

Even loose powders generally exhibit some degree of 

non-random grain orientation [1]. The consequences 

of non-random grain orientations – called preferred 

orientation – on any diffractive phase content 

determination are straightforward. Diffracted 

intensity is proportional to the phase content 

but now it becomes dependent on the specimen 

orientation. 

What is the most efficient way to measure the

retained austenite content in steel by diffraction? The 

apparently exhaustive answers provided by both 

ASTM standards and SAE recommendations reveal 

weaknesses when examined critically. The question 

of how to deal with the orientation dependence is 

crucial because preferred orientation is the greatest 

source of uncertainty for RA measurements. One 

can a) presume complete randomness; b) prescribe 

varying orientation averaging schemes or c), 

determine the orientation density function and use it as a 

correction. Option a) is never justified because there is no

steel without some degree of preferred orientation. The 

dangers of option a) are best illustrated by the withdrawal 

of a previous NIST austenite standard reference material 

whose production was based on the premise of sufficient

randomness. Option c) in the context of Rietveld 

refinement is deemed the best but also the costliest way

in terms of instrumental and time requirements. Option 

b) is left as the most sensible approach because of modest 

instrumental requirements, and it is, together with some 

procedural recommendations, part of the two standard 

measurement procedures for RA content. Therein lies the 

rub: the averaging procedures described do not withstand 

a critical examination (sample orientations do not have 

equal weight, which is disregarded; only a small fraction 

of orientation space is used), and the error estimation is 

incorrect.

How is orientation averaging performed correctly? This 

has been answered already, albeit for a different context 

– the determination of the grain orientation density 

function (ODF) [2]. The most efficient way to determine

the ODF is to measure intensities at specimen orientations 

that form an equidistant net on the pole sphere (where 

the specimen orientation in spherical polar coordinates 

1University of Maryland, College Park MD 20742

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

3Metallurgy Division, National Institute of Standards and Technology, Gaithersburg MD 20899-8553

FIGURE 1: Regular hexagonal grid and the reverse equal-area 

projection of the centers of the hexagons onto a sphere. The locations 

on the sphere are the spherical coordinates of sample tilt y and 

sample rotation j.
NCNR 2010 Accomplishments and Opportunities 23

(j,y) meets the unit sphere). However, it is not possible to 

divide the surface of a sphere into equal, regular polygons. 

On the other hand, coverage through equal hexagons 

is straightforward for a plane. One can achieve a nearequidistant mesh on the pole sphere through the following 

procedure: project the sphere on a plane in equal-area 

projection, then sample the projected sphere with a regular 

hexagonal grid of chosen resolution, and “back-project” the 

grid into true spherical space. 

Added up, the same mesh of specimen orientations also 

forms a complete orientation average which requires 

neither any corrections nor the ODF itself because 

ultimately only the sum peak is needed for a RA content 

measurement [1]. Note that the complete orientation 

average is most easily achieved with neutron diffraction. 

Due to the high penetration there are no inaccessible 

orientations and the only corrections necessary is the 

subtraction of background. X-ray diffraction is surface

limited, (exception: high energy synchrotron diffraction) 

thus limiting the possible tilt range and the accessible 

region of orientation space (called partial averaging in the 

following). The method of complete orientation averaging 

with neutron diffraction addresses these problems and it 

establishes simple conditions for the minimum of necessary 

measurements to determine the austenite content. 

The method of complete orientation averaging provides 

only a partial answer to the problem of measuring a phase 

fraction in a textured material. The remaining questions 

concern which and how many reflections to measure,

and what number of orientations to choose for the mesh 

shown in Fig. 1. The selection of reflections follows in a

straightforward manner from basic statistical principles. In 

order to get any measure on the accuracy of the orientation 

average for one reflection it needs to be compared with

a suitable quantity. As there are no standard reference 

materials available this quantity can only be a different 

reflection measured on the same material with the same

orientation averaging. Both reflections are divided by their

respective theoretical intensities after which they become 

comparable – and the difference between the two values 

gives a direct measure of the deviation from the mean both 

of the averaging procedure and indirectly, the number of 

orientations used. The analysis of the latter is revealing 

because it sheds some light on the relationship between 

precision of the RA content measurement and number of 

orientations in the average (Fig. 2). The measurements 

were performed with sufficient counting time such that

uncertainties stemming from the counting statistics became 

negligible.

The most significant result to be taken from Fig. 2 is that,

depending on the averaging scheme the relative standard 

deviation of the measured RA fraction fg reaches a stable 

value (srel ≈ 10 %) spanning a range from fg = 1.6 % up

to fg = 14.1 %. However, precision is not to be confused

with accuracy. Whereas srel for partial averaging appears 

to reach the same stable value as the complete averaging 

scheme at y ≈ 30° - a value easily possible for most x-ray

equipment – the absolute values for fg draw a different 

picture. The complete averaging method fares well with 

stable values reached at >100 orientations (Fig. 3) but 

partial averaging needs tilt angles > 60° to reach the same 

value, thus becoming essentially a complete average itself.

In summary, we can state that for the more than 40 

different samples investigated here the most efficient

way of measuring the retained austenite content - while 

providing both accuracy and precision - consists of using 

at least four reflections (two for ferrite/martensite, two

for austenite), each with at least 100 orientations in the 

complete averaging scheme described here. The most 

severe preferred orientation will require more orientations 

to be included in the averaging. This is best judged by 

the standard deviation where srel ≈ 10 % appeared as the

achievable limit.

FIGURE 2: Relative standard deviations of fg for the complete 

averaging scheme (bottom axis) and for partial averaging in limited 

y-tilt (top axis). Low values on the top axis mean fewer orientations 

just as on the bottom axis.

FIGURE 3: Comparison of the retained austenite content fg as 

obtained from complete and partial averaging schemes for 

undeformed TRIP700. The partial averaging is typically used in surface 

limited x-ray diffraction. For the standard deviations, see Fig. 2. Note 

that at psi- angle of 90° partial average becomes complete.

References

[1] T. Gnäupel-Herold, A. Creuziger, submitted to Mat. Sci Eng. A.

[2] S. Matthies, H.-R. Wenk, Phys. Stat. Sol. A 133, 253 (1992).
24Engineering

24

Probing artificial muscles with neutrons

J. K. Park1, R. B. Moore1, P. J. Jones2, C. Sahagun2, S. E. Morgan2, K. A. Page3, D. S. Hussey4, 

D. L. Jacobson4, M. Arif4

I

onic polymer metal composites (IPMCs) are a class 

of materials with similarities to biological muscles 

that exhibit actuation due to electrical stimulation, 

and are often referred to as artificial muscles [1].

Although IPMCs have been studied for more than 

ten years, the exact actuation mechanism is still 

not well understood. IPMCs are based on a solid 

polymer electrolyte, which is plated on both surfaces 

by dense layers of metal nanoparticles (e.g., platinum 

or gold) to serve as conductive electrodes. 

FIGURE 1: IPMC actuation under applied electrical voltage. 

Each image was captured at the position of X on the excitation 

square wave.

This structure resembles the membrane electrode 

assemblies (MEAs) used in fuel cells. Under 

the stimulus of a relatively low electric field

(2 V to 3 V), IPMCs are capable of undergoing 

significant mechanical bending motion; an

example of this is shown in Fig. 1. Conversely an 

external mechanical force applied to the surface 

of an IPMC can stimulate a detectable electrical 

response [2]. 

The vast majority of work on IPMCs has 

utilized the perfluorosulfonate ionomer (PFSI)

Nafion, a copolymer of tetrafluroethylene with

perfluorovinylether units terminated with

sulfonic acid functionalities. This material has 

received considerable attention due to the unique 

nanophase-separated morphology observed upon 

aggregation of the polar, ionic moeities within the 

hydrophobic polytetrafluoroethylene (PTFE) matrix.

There have been numerous small angle x-ray and 

neutron scattering studies performed to elucidate 

the morphology of Nafion and to propose detailed

models for this technologically important material as an 

ionic conductor. From this body of work, it is generally 

accepted that there are continuous pathways that allow 

transport of ions and water [3,4] and recent studies have 

suggested that these pathaways may be elongated, locally 

parallel water channels [4,5].

One proposed mechanism for IPMC actuation that 

has commonly been discussed in the literature is an 

electrophoresis-like counterion and water redistribution 

within the nanostructured ionomer membrane [6-8]. Since 

the ionic polymer is negatively 

charged with protons or alkalimetal cations as the counterions, 

these mobile cations in the hydrated 

membrane readily redistribute in 

response to an applied electric field

to create cation-rich and cationpoor boundary layers near the 

electrode/membrane interfacial regions as is shown if Fig. 

2. As cations migrate toward the cathode, they drag along 

1Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 

2The University of Southern Mississippi, Hattiesburg, MS 39406

3Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD 20899

4Physics Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899

FIGURE 2: (a) Illustration of the equilibrium state between sulfonate 

groups and protons in the PFSI membrane with no applied bias, 

(b) illustration of proton and water migration to the negatively 

charged substrate and formation of isolated sulfonate-rich domains 

and dehydration on the top surface of the PFSI membrane, and (c) 

illustration of proton and water migration away from the positivelycharged substrate forming a cationic film on the top surface of the PFSI 

membrane and neutralization of the positively charged substrate by 

non-mobile sulfonate ions.
NCNR 2010 Accomplishments and Opportunities 25

water molecules. This hydraulic action results 

in swelling near the cathode and contraction 

near the anode due to dehydration, leading 

to the bending force that curves the IPMC 

towards the anode. Other models of the 

bending are electrostatic in nature, due to 

local cation redistribution which leads to 

polymer chain relaxation or dipole-dipole 

interactions [9,10]. 

Experimental studies to validate/invalidate 

actuation models have utilized magnetic

resonance imaging (MRI) [11] and nuclear 

magnetic resonance (NMR) [12] methods, 

which showed greater proton density (PD) and 

higher water diffusion coefficients near the

cathode, respectively. In this study high resolution neutron 

radiography was used to directly measure the the water/

counterion redistribution under electrical stimulation 

predicted by the hydraulic model [1]. Recent improvements 

in neutron detectors allowed spatial resolution of 25 μm 

to be achieved. In addition to neutron imaging, this work 

also performed in situ atomic force microscopy studies of 

the IPMC surface to monitor changes in the morphological 

and surface characteristics that result from electrical 

stimulation. 

The results of the neutron imaging are shown in Fig. 3. 

Here the IPMC was oriented to allow neutrons to travel 

parallel to the anode and cathode surfaces. The resulting 

neutron transmission allows the mapping of water 

distributed through the plane of the IPMC from anode to 

cathode. In the figure, the image of the unstimulated state

is compared to the state after an electrical stimulus of 3 

V was applied for 30 s. The resulting change in neutron 

attenuation showed a rapid redistribution of water/

conterions in the IPMC when the electrical stimulus was 

applied. When the polarization of the applied electric

field is reversed the corresponding water/counterion

distribution is also rapidly reversed, in direct support of 

the hydraulic model for the deformation of the IPMC due 

to the applied electric potential. Additional measurements 

were made using D2O swollen IPMCs neutralized to

contain sodium and tetramethylammonium counterions 

were also studied to separate the cation motion from the 

hydraulic motion. These results showed that both the 

cations and water migrate under electrical stimulation. 

In further support of the bulk redistribution of water/

counterions obtained from neutron radiography, high 

resolution AFM studies were performed. These studies 

showed the hydration of the anode and dehydration of the 

cathode with the appearance of liquid pore like structures 

on the surface of negative polarity (cathode) of the IPMC 

and absence of liquid pores for the surface of positive 

polarity (anode).

The true mechanism of actuation for IPMCs remains under 

debate. However, the two methods used here, neutron 

radiography and atomic force microscopy, provide direct 

evidence that the actuation response involves a strong 

hydraulic contribution. After the application of an electrical 

field between the IPMC electrode layers, the mobile

cations and the hydraulic sheath rapidly move toward 

the negatively charged cathode. This gradient in water 

and counterion concentration across the ionic polymer 

membrane creates swelling on the cathode side and 

contraction on the anode side that results in a bending force 

that curves the IPMC toward the anode. When the polarity

is switched, both water and ions move rapidly across the 

ionic polymer film reversing the gradient and reversing the

curvature of the IPMC.

References

[1] J.K. Park, P.J. Jones, C. Sahagun, K.A. Page, D.S. Hussey, D.L. 

Jacobson, S.E. Morgan and R.B. Moore. Soft Matter, 6, 1444 (2010). 

DOI: 10.1039/b922828d.

[2] M. Shahinpoor, Electrochim. Acta, 48, 2343 (2003).

[3] K. A. Mauritz and R. B. Moore, Chem. Rev., 104, 4535 (2004).

[4] K. Schmidt-Rohr and Q. Chen, Nat. Mater., 7, 75 (2008).

[5] M.-H. Kim, C. J. Glinka, S. A. Grot and W. G. Grot,

Macromolecules, 39, 4775 (2006).

[6] M. Shahinpoor, Y. Bar-Cohen, J. O. Simpson and J. Smith, 

Smart Mater. Struct., 7, R15 (1998).

[7] P. G. De Gennes, K. Okumura, M. Shahinpoor and K. J. Kim, 

Europhys. Lett., 50, 513 (2000).

[8] M. Shahinpoor, Smart Mater. Struct., 3, 367 (1994).

[9] L. M. Weiland and D. J. Leo, Smart Mater. Struct., 13, 323 

(2004).

[10] S. Nemat-Nasser and J. Y. Li, J. Appl. Phys., 87, 3321 (2000).

[11] L. Naji, J. A. Chudek and R. T. Baker, Soft Matter, 4, 1879 

(2008).

[12] L. Naji, J. A. Chudek and R. T. Baker, J. Phys. Chem. B, 112, 

9761 (2008).

FIGURE 3: (a) Colorized images showing water/counterion -depleted zones represented 

by red pixels and water/counterion -rich areas represented by blue pixels. IPMC was 

subjected to 3 V DC. (b) Relative neutron optical density due to water/counterion 

gradient profile across the IPMC thickness.
Chemical Physics

Biology

26

‘Molecular headphones’, SANS and MD modeling 

of protein denaturing

P. E. Mason1, C. E. Dempsey2, G. W. Neilson3, S. R. Kline4, J. W. Brady1

Proteins are chains of amino acids that in aqueous 

media typically fold up into shapes with specific

and very efficient biological functions. For decades

now we have had a broad brush understanding of 

the forces that cause such folding: the interaction of 

the charged groups, hydrophilic and hydrophobic 

groups of the protein with both itself and with water, 

but a detailed understanding of these mechanisms 

has proved elusive. Our current research aims to gain 

a greater insight into the forces that cause proteins to 

fold up in solution by studying model systems that 

are easier to understand and quantify [1]. 

Broadly speaking, there are two types of hydrophobic 

groups in proteins, those that have a relatively high 

degree of curvature relative to the size of water

(‘knobbly’ hydrophobic groups such as valine) 

and those with a relatively flat surface such as the

indole group of tryptophan. In order to gain better 

insight into how these types of hydrophobic groups 

interact with each other, and how this interaction 

could be disrupted by denaturants (agents that 

cause a protein to lose its 3-D solution structure), 

we chose to examine some soluble analogues of 

these archetypal motifs. This solubility poses a 

bit of a problem as the hydrophobic systems we 

would ideally wish to study, just like oil and water are 

immiscible and if you attempt to mix them, they tend 

to simply phase separate into two layers. This led to the 

compromise of choosing molecules which were somewhat 

hydrophobic, but not hydrophobic enough to actually 

phase separate. The systems of isopropyl alcohol (rubbing 

alcohol) and pyridine in water were chosen as models for 

the ‘knobbly’ and ‘flat’ hydrophobic groups respectively,

and guanidinium chloride was chosen as the denaturant 

(Fig. 1). A multidisciplinary approach was taken with all 

of the systems being studied by both molecular dynamics 

(MD) and small angle neutron scattering (SANS), a method 

capable of gaining information about association of solutes 

in solutions.

In the molecular dynamics simulations of these systems 

it can be seen that the molecules preferentially associate 

with each other, showing that they are hydrophobic, 

although not hydrophobic enough to phase separate. 

Further examination of the pyridine system reveals that 

the main mechanism by which these flat aromatic groups

interact with each other is by a T-type interaction, but when 

1Cornell University, Ithaca, NY 14853

2University of Bristol, Department of Biochemistry, Bristol BS8 1TD, Avon England

3University of Bristol, HH Wills Physics Lab, Bristol BS8 1TL, Avon England 

4NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA

FIGURE 1: The size and shape of the molecules in this study, 

from left to right: isopropyl alcohol (knobbly) , pyridine (flat), 

guanidinium (as a denaturant), and water.

FIGURE 2: highlighted are the T-type interactions of the pyridine (red) 

and the stacking interaction of guanidinium (yellow) and pyridine 

(red). Guanidinium also interacts with itself in a stacking fashion 

(both yellow).
NCNR 2010 Accomplishments and Opportunities 27

the denaturant is added, it 

competes with this interaction, 

somewhat dispersing the 

aggregation of the hydrophobic 

groups. Interestingly, the 

denaturant, which is also a 

flat molecule, interacts with

pyridine in a similar stacking 

type interaction to that found 

between two guanidinium ions 

(Fig. 2).

This stacking interaction can 

be further quantified by the

examination of ‘density maps’, 

which are an average spatial 

representation of atoms around 

a central molecule. Here the 

earlier finding is re-enforced, with the exception that the

hydrogen bond interaction between the denaturant and the 

polar nitrogen of pyridine can be seen, giving the density 

map of guanidinium around pyridine the appearance of 

‘molecular headphones’ (Fig. 3).

It was found in the simulations that the knobbly 

hydrophobic group of isopropyl alcohol did not interact 

with itself as strongly as the flat hydrophobic group of

pyridine, nor was this interaction particularly disrupted by 

the addition of the flat denaturant guanidinium.

The average coordination number of the hydrophobic 

solute gives a measure of the aggregation of these species. 

Again the MD simulations showed that pyridine displayed 

a greater aggregation than isopropyl alcohol, and also that 

the clustering of pyridine was significantly dispersed by

the flat denaturant guanidinium, while the clustering of

isopropyl alcohol was relatively unaffected by its presence.

SANS at the NIST Center for Neutron Research allows the 

possibility to test the predictions of this model directly. 

SANS is sensitive to both the size and density of the

clustering, in this case of the hydrogen rich hydrophobic 

molecules, and hence offers direct structural insight into 

these solutions.

A correlation length model was fitted to the data of Fig. 4

(black lines), yielding a small correlation length (1.4 ± 0.1) 

Å for the isopropanol aggregates, and a larger length (4.5 ±

0.02) Å for the pyridine aggregates. This directly confirms

the MD prediction that the flat, aromatic groups associate

much more strongly than the knobbly ones. Also, as 

predicted by the simulations, the SANS data confirms that

the addition of denaturant has essentially no effect on the 

association of the knobbly hydrophobics, but significantly

disrupts the aggregation of flat hydrophobic groups,

reducing the correlation length to (2.7 ± 0.05) Å.

This combination of simulations and experiment confirms

the geometry-dependent interactions of hydrophobic 

molecules with both each other and with a protein 

denaturant, yielding a valuable insight into the details of 

the driving forces that cause proteins to fold as they do.

Reference

[1] P. E. Mason, C. E. Dempsey, G. W. Neilson, S. R. Kline, J. W.

Brady, J. Am. Chem. Soc. 131 , 16689 (2009).

FIGURE 3: Left, the density maps of pyridine around pyridine (white 

is hydrogen on pyridine, red, carbon on pyridine) showing the T-type 

interaction (the white cloud closer to the pyridine than the red cloud), 

and right, the ‘molecular headphones’ of the density of guanidinium 

around pyridine (white is H on guanidinium, purple, nitrogen on 

guanidinium) showing the stacking type interaction (the white cloud 

within the purple cloud).

FIGURE 4: Blue data points are the small angle neutron scattering data for 3 mol/kg (molal) isopropyl 

alcohol/water (left) and 3 mol/kg pyridine/water (right) solutions, while the red data points are the same 

solutions after the addition of the denaturant guanidinium chloride, at an equal concentration of 3 mol/

kg guanidinium chloride /water. It is clear that the addition of denaturant has no effect on the clustering 

of the knobbly hydrophobic group (isopropyl alcohol), while the clustering of the flat, hydrophobic 

group (pyridine) is significantly reduced.
Chemical Physics

Biology

28

Coordinatively-unsaturated metal-organic 

frameworks for hydrogen storage

W.L. Queen1,2, C.M. Brown1, K. Sumida3, J.R. Long3

One of the greatest obstacles in the pursuit of a hydrogen-based economy is how to store 

enough gas on board a vehicle to achieve driving 

ranges similar to those observed with gasoline 

powered automobiles. Although a gram of hydrogen 

gas has three times the energy content of a gram 

gasoline, a liter of hydrogen gas at one atmosphere 

has only a third the energy content of a liter of 

gasoline. One solution to this problem has been 

the development of new materials that physisorb 

H2 molecules. Metal-organic frameworks (MOFs) 

are currently under intense investigation for gas 

storage and separation applications, due to their 

high internal surface areas, convenient modular 

synthesis, and chemical tunability. These materials 

typically exhibit low binding energies ranging from 

−5 kJ/mol to −7 kJ/mol due to weak dispersivetype interactions between the adsorbed H2 and 

framework. As a result, at room temperature they 

provide little to no improvement over the current 

storage densities achieved through the simple 

compression of hydrogen into holding tanks. 

An effective strategy to improve binding energy 

(optimal projected values are −15 kJ/mol to −25 kJ/

mol for storage at room temperature) and enhance 

surface packing density of adsorbates is through the 

generation of new MOFs that, upon solvent removal, 

contain high concentrations of coordinatively 

unsaturated metal centers (UMC) on the framework 

surface [1,2]. In this report, we show that crucial gas 

adsorption properties, such as binding energy and 

selectivity can be further improved through chemical 

substitution of the UMC [3]. It is thought that the 

addition of UMC’s with higher charge densities can 

induce larger dipoles in the adsorbed gas creating an 

overall increase in the binding strength.

Fe3[(Fe4Cl)3(BTT)8(MeOH)4]2 (Fe-BTT) a sodalitetype MOF having exposed Fe2+ sites and a Brunauer, 

Emmett and Teller (BET) surface area of 2010 m2/g, 

has proven to be efficient at storage of H2. Although 

Cu2+ and Mn2+ derivatives have previously been 

studied by us [4,5], the iron analog has shown a 

significant improvement in the binding enthalpy of

H2, −12 kJ/mol compared to −10.1 kJ/mol and −9.5 kJ/

mol for Mn2+ and Cu2+ cations, respectively. In fact, at 

room temperature, this new material has H2 binding that 

is among the strongest reported to date, a property that is 

directly reflected in the observed room temperature uptake

equal to 1.1 % mass fraction and 8.4 g/L at 100 bar.

In order to understand more about the framework/

gas interactions in Fe-BTT, we have performed neutron 

diffraction experiments, using the high resolution 

neutron diffractometer (BT-1). Data for the bare sample 

reveals nuclear scattering density near the open Fe2+ site 

corresponding to 30 % occupancy of methanol due to 

incomplete solvent removal. This number indicates that 

Fe-BTT has a similar concentration of UMCs compared to 

its Mn counterpart. Low temperature neutron diffraction 

data were collected again after the sample was sequentially 

dosed with (4, 8, 20, 33, 65, and 98) D2 per formula unit. 

The strongest adsorption site, I, found in close proximity 

to the unsaturated Fe2+ is the first site occupied at low

gas loadings, Fig.1. There is a remarkably short Fe2+-D2

distance of 2.17(5) Å, the shortest metal–D2 distance yet 

observed in a MOF. This observation is consistent with 

significantly stronger binding energy compared to MnBTT and Cu-BTT, which exhibited metal–D2 distances of 

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

2University of Maryland, College Park, MD, 20742 

3University of California, Berkeley, CA, 94720

FIGURE 1: Atomic structure of Fe-BTT consists of chlorine centered 

[Fe4Cl]7+ units linked by BTT3- ligands. Orange, green, gray, and 

blue spheres represent Fe, Cl, C, and N atoms, respectively. Solvent 

molecules, H atoms, and charge-balancing cations are omitted for 

clarity. A close up view of the portion of the framework highlighted 

in orange is shown on the right. The D2 binding sites (yellow) within 

Fe-BTT were determined from Rietveld analysis of the powder 

neutron diffraction data. At higher D2 loadings there were 6 additional 

occupied sites (not shown). While these additional sites were all 

localized, their binding strengths are typical for weak dispersive 

interactions, as reflected in a framework–D2 distances which are all 

greater than 3.6 Å. 
NCNR 2010 Accomplishments and Opportunities 29

2.27 Å and 2.47 Å, respectively [4,5]. The close approach of

the adsorbed gas to the framework surface is essential for 

achieving a high storage density at cryogenic temperatures.

At higher D2 loadings, additional adsorption sites become 

evident. The next strongest binding position, II in Fig. 1, 

is situated approximately 3.44 Å above the chloride ion

of the [Fe4Cl]7+ unit with four tetrazolate rings within

3.60 Å of the site, forming a bowl-like adsorption pocket

with a negative surface charge. Up to a loading of 8 

D2 molecules per formula unit, only sites I and II are 

occupied, suggesting that they have much higher binding 

enthalpies than the subsequently occupied sites. At higher 

loadings, site III D2 molecules are found in the openings 

of the sodalite-type cages, with a 3.45 Å distance from

the N2 atoms of four tetrazolate ligands, while site IV

is located in the channels of the structure, with the D2

centroid 3.16 Å from the plane of two tetrazolate rings.

Although it is not further discussed here, comparison of the 

D2 adsorption sites of Fe-BTT and its Mn and Cu analogs 

reveals several differences related to the binding strengths 

of sites III and IV, presumably due to slight differences in 

unit cell dimensions and the distinct position of the extraframework metal cations. 

To complement our neutron diffraction studies, we 

collected inelastic neutron scattering data to probe the 

rotational spectra of Fe-BTT as a function of H2 loading, 

Fig. 2. The peaks represent neutron energy loss due to 

transitions in the H2 rotational levels. For free hydrogen, a 

single peak corresponding to the first rotational transition

from J = 0→1 is expected at 14.7 meV; however, when H2

strongly interacts with the surface of an adsorbent there is 

a hindrance to rotation causing changes in the position and 

splitting of the J = 1 level. At the lowest loading, there is a

lack of a distinct peak at or below 14.7 meV, which could 

indicate a extremely strong interaction of H2 with the Fe2+

ion, pushing the transition out of the available spectral 

window, Fig. 2(a), with phonon-rotation combination peaks 

at higher energies. At loadings up to 0.5 % mass fraction we 

observe two additional rotational lines at approximately 

13.2 and 19.7 meV corresponding to a 1-dimensional 

rotational barrier of ≈ 15 meV, indicative of a moderate

barrier for H2 on site II. As sites III and IV become more 

populated in the 1.25 % and 2.0 % mass fraction data, there 

are rotational lines that appear close to free H2, indicating 

an even lower rotational barrier. The highest loadings, 

4.0 % and 6.0 % mass fraction, exhibit very broad indistinct 

features at higher energy (> 20 meV), characteristic of 

molecular recoil from weakly bound hydrogen. Also, at 6 % 

mass fraction, there is the appearance of a shoulder on the 

most intense peak, which is at a frequency characteristic of 

bulk hydrogen. 

The two spectra of Fe-BTT loaded with 0.1 % mass 

fraction normal-H2 (n-H2) and para-H2 (p-H2), where only 

site I is occupied, are superimposible indicating a full 

interconversion of n-H2 (25 % para-H2, and 75 % ortho-H2

at room temperature) to p-H2, a process catalyzed by the

paramagnetic high-spin Fe2+ centers. At the 4 % mass 

fraction loading, the scaling factor of p-H2/n-H2 is 1.2, Fig 

2(b), indicative of an incomplete conversion. It is thought 

that there is an initial conversion occurring as the gas is 

loaded at 50 K because H2 can gain access to Fe2+, but as the 

sample is cooled to collect data, the gas becomes localized

in sites that are distant from the metal, reducing H2-Fe2+

interactions and freezing the para–ortho ratio.

This study features a sodalite-type MOF whose properties, 

such as binding energy, can be systematically tuned 

through chemical substitution. The Fe-BTT framework 

has a high initial isosteric heat of adsorption, −12 kJ/mol,

and enhanced storage capacity at 298 K, both of which 

are directly related to the coordinatively unsaturated 

Fe2+ cation as determined by neutron diffraction and 

inelastic neutron scattering. Gas adsorption measurements 

combined with neutron diffraction data and inelastic 

neutron scattering spectroscopy have provided us a clearer 

understanding of the adsorption process that will be useful 

for the future optimization of storage/separation materials.

References

[1] S. K. Bhatia, A. L. Myers, Langmuir, 22, 1688 (2006).

[2] Y. Liu, H. Kabbour, C. M. Brown, D. A. Neumann, C. C. Ahn, 

Langmuir, 24, 4772 (2008).

[3] K. Sumida, S. Horike, S.S. Kaye, Z.R. Herm,W.L. Queen, C.M.

Brown, F. Grandjean, G.J. Long, A. Dailly, J.R. Long, Chem. Sci, In 

press (2010).

[4] M. Dincă, A. Dailly, Y. Liu, C. M. Brown, D. A. Neumann, J. R.

Long, J. Am. Chem. Soc., 128, 16876 (2006).

[5] M. Dincă, W. S. Han, Y. Liu, A. Dailly, C. M. Brown and J. R.

Long, Angew. Chem., Int. Ed., 46, 1419 (2007).

FIGURE 2: Inelastic neutron spectra at several hydrogen loadings 

following subtraction of the spectrum of evacuated Fe-BTT. (a): lowest 

n-H2 data up to 2.0 % mass fraction. (b) higher n-H2 loadings up to 6 

% mass fraction, and p-H2 at 4 % mass fraction. In both panels, the 

dashed line represents the expected energy transfer of 14.7 meV 

corresponding to the first rotational transition (J = 0→1) for free 

hydrogen. 
Chemical Physics

Biology

30

Graphite oxide framework (GOF) materials 

for hydrogen storage

J. W. Burress1, S. Gadipelli1,2, J. Ford1,2, J. M. Simmons1, W. Zhou1,3, T. Yildirim1

Vehicles and other systems powered by hydrogen fuel cells emit only water as a waste product. 

Thus, adoption of this technology would reduce 

greenhouse gas emissions by reducing dependency 

on fossil fuels. An important challenge, however, 

is storing enough hydrogen on board to provide a 

range comparable to that of a vehicle powered by 

fossil fuels. Unfortunately, current materials still lack 

the ability to store necessary amounts of hydrogen 

under technologically useful conditions. Hence, there 

is urgent need for new ideas and materials to solve 

the hydrogen storage problem.

In this study [1], we show that graphene oxide (GO), 

a substance known for more than a century, can be 

easily turned into a potentially useful gas storage 

material. GO is a sheet of carbon atoms with many 

hydroxyl, epoxide and carboxyl surface groups. In 

principle, hydrogen can be stored between layers of 

this lightweight material. However, the challenge 

is to separate the layers without filling the space

between them. Here we show that by using the 

well-known chemistry between boronic acids and 

hydroxyl groups, GO layers can be linked together 

to form a new layered structure (see Figs. 1 and 2). 

Such GOF structures can have tunable pore widths, 

volumes, and binding sites depending on the linkers 

chosen, and could exhibit interesting gas sorption 

properties.

To evaluate the potential of GOF materials for H2 storage, 

we performed theoretical Grand Canonical Monte Carlo 

(GCMC) simulations. A series of idealized, model systems

with various diboronic acid linker concentrations were 

examined. Structural optimization yielded ≈ 1.1 nm

interlayer separations for these ideal structures. The 

simulated absolute hydrogen adsorption isotherms at 77 

K for several representative GOF structures are shown 

in Fig. 2. When the linker concentration is too high, the

GOF structure is too dense and contains no accessible 

pores. Consequently, there is no H2 uptake. As the linker 

concentration decreases, the GOF specific pore volume

increases and eventually reaches the limit of no linker 

present. Naturally, a GOF structure with lower linker 

concentration would possess higher H2 adsorption 

capacity. However, low linker concentration will lead to 

low structural stability and reduced graphene interlayer 

separation. Therefore, these factors must be balanced to 

optimize the linker concentration. The GOF-32 structure

with one linker per 32 graphene-carbons (Fig. 2) appears 

to be one reasonable choice, as it is structurally stable 

(according to density functional theory lattice dynamics 

calculation), while possessing an H2 adsorption capacity 

(≈ 6.1 % mass fraction H2 uptake at 77 K and 1 bar) that 

is predicted to be higher than any other porous material 

known. Overall, our simulation results were quite 

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

2University of Pennsylvania, Philadelphia PA 19104

3University of Maryland,, College Park, MD 20742

FIGURE 1: A schematic view of boronic-ester (top) and GOF 

formation (bottom). Idealized graphene-oxide framework 

(GOF) materials proposed in this study are formed of layers 

of graphene oxide connected by benzene-diboronic acid 

(B14DBA) pillars.

FIGURE 2: The GCMC simulations for ideal GOF-n structures with 

n-graphene carbons per linker.
NCNR 2010 Accomplishments and Opportunities 31

encouraging and strongly motivated us to experimentally 

pursue these materials.

We synthesized samples containing varying amounts

of linker and characterized them with powder x-ray

diffraction. As shown in Fig. 3, we observed a controllable, 

monotonic increase in the interlayer spacing in the GOF 

samples, from 0.75 nm to 1.05 nm. This, combined with 

neutron prompt gamma activation analysis (PGAA) shown 

in Fig. 4(b), indicates that the boronic acid is intercalated 

in the GO and that the sample prepared with a 1:1 ratio of 

GO:linker roughly corresponds to GOF-33. 

As shown in Fig. 4(a) the inelastic neutron scattering (INS) 

spectra of GOF differs significantly from the INS spectra

of GO and resembles the calculated INS spectra of GOF32, further supporting that the synthesized materials are

structurally similar to our ideal GOF systems shown in 

Figs. 1 and 2. The x-ray photoelectron spectroscopy (XPS)

normalized to the graphitic carbon peak at 285 eV is shown

in Fig. 4(c). It indicates that the O/C ratio of 0.43 in GO is 

reduced down to ≈ 0.33 in the GOF materials. The peak

near 287 eV corresponds to carbon with singly-bonded 

C-O chemistries and its intensity increases with linker 

concentration as expected for boron-ester cross-linked 

graphene layers. Thermogravimetric analysis revealed 

a 100 °C increase in the exfoliation temperature with the 

GOFs, again supporting interlinking of GO planes. 

The porosity and gas storage capacity of GOF samples were 

measured with nitrogen and hydrogen and CO2 sorption 

isotherms. The nitrogen Brunauer, Emmett and Teller (BET) 

surface area reaches a maximum for the 1:1 GO:linker GOF 

at 470 m2/g as compared to ≈ 20 m2/g for the GO-control. 

Despite this low surface area, GOF exhibits a H2 uptake 

of 1 % mass fraction at 1 bar at 77 K compared to 0.2 % 

mass fraction for the GO-control. The initial isosteric 

heat of hydrogen adsorption was determined to be 

Qst ≈ 9 kJ/mol, twice as large as for a graphene sheet and

typical metal-organic framework (MOF) materials such as 

MOF-5 and comparable to MOFs with open metal centers. 

The INS spectra of H2-loaded GOF shows a peak around 

10 meV, suggesting very strong hindered rotation due to 

a strong binding potential which confirms the large Qst. 

Compared to the simulation results, the experimental 

H2 uptake achieved so far in our GOF material is less 

than expected for an ideal GOF structure and only 30 % 

greater than that typical for activated carbons. This is most 

probably due to presence of unreacted functional groups 

in our initial GOF materials. This is supported by the large 

O/C ratio that we obtained from XPS data shown in Fig.

4(c). The O/C ratio for our ideal GOF-32 is 4/32 ≈ 0.13,

significantly smaller than the current experimental ratio of

0.35. Clearly, there is significant room for optimization.

In conclusion, we have successfully shown that graphene 

oxide layers can be used as building blocks for new 

nanoporous materials by interlinking them with diboronic 

acid. Considering the rich boron chemistry and large 

number of different types of boronic acids, it is quite 

possible that there are other linkers that will perform better 

than the B14DBA used in this study. We hope that our

theoretical predictions and the first experimental results

reported here will start a new research direction based on 

cheap and environmentally friendly GO as a building block 

for new nanoporous materials with better gas adsorption 

properties.

References

 [1] J. W. Burress, S. Gadipelli, J. Ford, J. M. Simmons, W. Zhou, T.

Yildirim, Angew. Chem. Int. Ed. 49, 1 (2010). FIGURE 3: X-ray diffraction and the corresponding interlayer 

d-spacing versus linker concentration. The dashed-line indicates the 

optimized d-spacing of 11 Å that was calculated for GOF-32 shown in 

Fig. 2.

FIGURE 4: (a) INS spectra of GO and GOF 1:1 sample and a model 

calculation based on GOF-32 structure. (b) The major boron 

peaks normalized to carbon peak in PGAA spectra, indicating the 

approximate relations between GO:Linker samples and the ideal 

GOF-n structures. (c) XPS O 1s and C 1s core level spectra for GO and 

three different GOFs.
Chemical Physics

Biology

32

New insight into the crystal structure of highly 

piezoelectric PZT: a single crystal diffraction study

D. Phelan1, P. M. Gehring1, X. Long2, Y. Xie2, Z. -G. Ye2, A. M. Glazer3, H. Yokota4, P. A. Thomas5

PbZr1-xTixO3 (PZT) exhibits exceptionalpiezoelectricity (the production of a voltage

when a material is squeezed) even though the parent

piezoelectric compounds PbZrO3 and PbTiO3 do 

not. For this reason, PZT ceramics have long been

the material of choice for use in device applications 

that require the conversion between mechanical and 

electrical energy, common examples being medical 

ultrasound imaging, sonar, and microphonics. Any 

fundamental understanding of this phenomenon 

requires a detailed knowledge of how the PZT crystal

structure changes when the two parent compounds 

are mixed. In particular, scientists wish to understand 

why the piezoelectricity in PZT is optimal for Ti

contents close to x = 0.5. Yet for decades such efforts

have been stymied because researchers have had 

to rely on x-ray and neutron powder diffraction 

methods, and subtle differences between certain 

crystal structures cannot be resolved through powder 

diffraction alone. As a result no consensus exists 

on the detailed phase diagram of PZT over a very

wide range of Ti concentration. Recently, chemists 

at Simon Fraser University (SFU) achieved a major 

breakthrough by growing the first high quality

single crystal specimens of PZT. Here we highlight

our neutron diffraction measurements on them, the 

first ever on single crystal PZT, which provide new

insights into the crystal structures in the region of 

interest.

The structural phase diagram of PZT, along with

some of its unresolved features, is depicted in Fig. 

1(a). The nearly vertical line near x = 0.5 is the wellknown morphotropic phase boundary (MPB) that 

separates Ti-rich (tetragonal) from Ti-poor regions; it 

is also the compositional range that displays the best 

piezoelectric properties. Knowing how the crystal

structure evolves across this phase boundary is 

widely regarded as being of the utmost importance 

in order to understand the piezoelectric mechanism.

In particular, one of the unresolved issues is 

whether the room temperature structures for Ti-poor 

compounds are rhombohedral or monoclinic. This is 

important because the direction of the electric polarization

is directly related to the crystal symmetry. If the symmetry 

is rhombohedral, then the polarization is restrained

uniaxially; but if the symmetry is monoclinic, then the Pbatom is free to move within a mirror plane, which allows 

the polarization to rotate within that plane. This seemingly

minor detail becomes significant when the crystal is

perturbed by an electric field or external stress, and it has

important implications for the piezoelectricity.

One of the problems with Rietveld refinement of highly

pseudosymmetric materials like PZT is that many models

refine to very similar agreement factors, which makes it

difficult to choose between them. A different approach

is based on the search for superlattice peaks that appear 

when the primitive unit cell is doubled, for instance in the 

presence of oxygen octahedra rotations; observations of 

such peaks (or the lack thereof) place severe constraints on 

the allowed symmetries. An important model of the PZT

structure proposes a monoclinic ground-state structure 

(space group Cc [1]) that should generate a very weak 

superlattice reflection at the reciprocal lattice position 1⁄2 1⁄2

1⁄2. (Indexing throughout is given with respect to a primitive

cubic unit cell.) However, it has proven impossible to prove 

1NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA

2Simon Fraser University, Burnaby, BC, V5A 1S6, Canada

3University of Oxford, Parks Road, Oxford OX1 3PU, UK

4University of Tokyo, Tokyo 113-8656, Japan

5University of Warwick, Coventry CV4 7AL, UK

FIGURE 1: (a) The PZT phase diagram and its ambiguities as currently 

understood. Data are taken from Ref. 3 (black circles), Ref. 4 (blue 

squares), and Ref. 1 (red triangles). RHT, MHT and RLT, MLT represent 

possible rhombohedral and monoclinic high- and low-temperature 

phases, respectively. The possibility of an I4cm superlattice phase is 

suggested in Ref 5. (b) The difference diffraction pattern (20 K to 

400 K) for a 20 g PZT x = 0.3 powder sample measured on BT-9. 
NCNR 2010 Accomplishments and Opportunities 33

or rule out this model using powder diffraction, even 

though no such peak was observed by powder neutron 

diffraction (see Fig. 1b) due to the fact that the model 

predicts a very weak structure factor.

Neutron diffraction measurements were performed on 

two PZT crystals with compositions far from (x = 0.325)

and close to (x = 0.460) the MPB using thermal (BT-9)

and cold (SPINS) triple-axis spectrometers located at the 

NCNR. We attempted to determine the phase symmetry

by searching for weak superlattice peaks. Fig. 2 shows data 

taken at variety of reciprocal lattice positions, and only 

peaks corresponding to a rhombohedral symmetry (space 

group R3c) due to octahedral tilting were observed. No 

Bragg peak was seen at 1⁄2 1⁄2 1⁄2; instead, we can say with

99 % confidence that any 1⁄2 1⁄2 1⁄2 peak intensity is less than

0.002 % of the fundamental 100 Bragg peak. This extremely 

restrictive upper bound effectively proves that the ground 

state crystal symmetry for PZT cannot be monoclinic Cc.

FIGURE 2: All panels are for x = 0.325 except (d) which includes 

x = 0.460: (a-c) Radial scans through the M and X points reveal 

no superlattice reflections at 35 K. (d) Scans performed using two 

different wavelengths through an R1 point. The dependence of the 

peak on wavelength is indicative of a multiple-scattering effect. 

(e) Scans through one R2 point at various temperatures are consistent 

with a rhombohedral distortion. (f) Order parameters of the 

superlattice phases at two concentrations.

A second monoclinic phase (Cm) that generates no 

superlattice reflections has also been proposed for PZT [2].

In order to search for the presence of the Cm phase, the 

radial linewidth of the 200 Bragg reflection was measured

as a function of temperature because it should remain a 

resolution-limited singlet under rhombohedral symmetry 

but should split if there is a monoclinic distortion. To 

observe very subtle changes in the linewidth, the best 

FIGURE 3: Radial scans through the 200 Bragg reflection at selected 

temperatures. Data from Ref. [6] on single crystal SrTiO3 are 

represented by green triangles.

possible wave-vector resolution was needed. The 220 

reflection from a perfect Ge single crystal was employed as

an analyzer because the near perfect matching of the 200

and 220 d-spacings from PZT and Ge provides an almost

optimal resolution condition. Fig. 3 shows the results of 

radial scans through 200 as a function of temperature. 

Although small, a significant change in the linewidth

was observed at the lowest temperature along with a 

slight peak asymmetry, which is consistent with a very 

small monoclinic distortion. Thus, as we have observed 

a broadening of 200, but at the same time superlattice 

reflections consistent with R3c, the most likely ground-state 

is a two-phase mixture of R3c and Cm.

We have performed the first single-crystal neutron

diffraction measurements on PZT. Our measurements

effectively eliminate one of the two major models, 

which proposes a monoclinic Cc ground-state, and 

instead suggests that the ground state structure of PZT

consists of coexisting R3c and Cm phases, and that such 

phase coexistence may play an important role in the 

piezoelectricity. The availability of single crystals will also

allow us to study other aspects of PZT; in particular, we

have already begun to investigate the lattice dynamics 

(phonons) and diffuse scattering of these crystals at the 

NCNR. 

References

[1] D. Pandey, A. K. Singh and S. Baik, Acta Crystallogr. A64, 192 

(2008).

[2] H. Yokota and N. Zhang and A. E. Taylor and P. A. Thomas

and A. M. Glazer, Phys. Rev. B 80, 104109 (2009).

[3] B. Jaffe, W. R. Cook, and H. Jaffe Piezoelectric Ceramics 

(Academic Press, London and New York, 1971).

[4] B. Noheda et al. Phys. Rev. B 63, 014103 (2000).

[5] I. A. Kornev, L. Bellaiche, P.E. Janolin, B. Dkhil, and E. Suard, 

Phys. Rev. Lett. 97, 157601 (2006).

[6] G. Xu, P. M. Gehring, V. J. Ghosh, and G. Shirane, Acta Cryst.

A60, 598 (2004).
Chemical Physics

Biology

34

Multiple filling of voids improves thermoelectric 

efficiency of skutterudites

J.R.D. Copley1, J.B. Leão1, J.J. Rush1,2, X. Shi3,4, Jihui Yang3, H. Wang5, M. Chi5, J.R. Salvador3, 

Jiong Yang6, S. Bai6, W. Zhang6, and L. Chen6

I

n a thermoelectric device, a temperature difference 

is induced by the flow of electric current across

the material. It follows that those materials favoring 

the flow of electricity while offering resistance to

the flow of heat are preferred for such devices. This

idea is incorporated in the concept of a PhononGlass-Electron-Crystal (PGEC) [1]. The types of 

materials that possess PGEC properties are usually 

open structure compounds, such as skutterudites 

and clathrates, containing large crystallographic 

voids. The idea is that the crystal-like electrical 

properties (favoring electrical flow) are provided by

the framework atoms, whereas the very low lattice 

thermal conductivity (kL) (or resistance to heat flow)

is realized by introducing guest atoms (or “fillers”)

into the nanometer-size voids. Indirect evidence of

phonon-glass behavior in cage-structured materials 

has come from observations such as strongly 

temperature-dependent atomic displacement 

parameters of the fillers, low values of kL, and sharp 

filler atom peaks in the phonon density of states.

The inelastic neutron scattering study of single- and 

multiple-filled skutterudites highlighted in this

article was undertaken to look for direct evidence in 

support of the phonon-glass concept.

The atomic structures of our samples were 

first examined using high resolution Scanning

Transmission Electron Microscopy (STEM). Figure 1 

shows high angle annular dark-field (HAADF) STEM

images in the [001] direction for the multiple-filled

skutterudite Ba0.08La0.05Yb0.04Co4Sb12, using a beam 

size of ≈ 0.6 Å. The population of guest atoms is

directly probed along the [001] direction, since filleronly atomic columns can be identified. The obvious

intensity variation among the filler columns suggests

that the guest atoms are randomly distributed within 

the voids of the host material.

The validity of the mechanism of multiple 

independent fillers scattering a broad range of host

lattice phonons, leading to significant reductions

in kL, hinges upon the phase incoherence of the filler

vibrations, and inelastic neutron scattering is a unique 

tool to study such incoherence. It measures the scattering 

function S(Q,E), where Q and E are the wave vector transfer 

and energy transfer respectively. If the filler vibrations are

phase incoherent, the difference function DS(Q,E0), which is 

the difference between the scattering functions for the filled

and unfilled materials evaluated at E0, the energy of one of 

the localized filler modes, is expected to vary as Q2.

Room temperature inelastic neutron scattering spectra 

were obtained using the Disk Chopper Spectrometer 

(DCS). Most of the measurements were performed using 

2.35 Å incident neutrons with an energy resolution of

≈ 0.7 meV at 5 meV energy loss. The complicated spectrum

for the unfilled structure (Fig. 2), particularly between

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

2University of Maryland, College Park, MD 20742

3Materials and Processes Laboratory, General Motors R&D Center, Warren, MI 48090

4Optimal Inc., Plymouth, MI 48170

5Oak Ridge National Laboratory, Oak Ridge, TN 37831

6Chinese Academy of Sciences, Shanghai 200050, China

FIGURE 1: A typical HAADF-STEM image of a Ba, La, and Yb-filled 

skutterudite sample along the [001] direction. The intensity profile 

shows fluctuations in filler concentration among the atomic columns. 

The left inset shows the filler in the void concept.

FIGURE 2: A comparison of 4.8 Å neutron energy gain data for the 

normalized unfilled CoSb3, and for Ba0.09La0.07Yb0.08Co4Sb12. 
NCNR 2010 Accomplishments and Opportunities 35

6 meV and 16 meV, precludes unambiguous identification

of resonant modes in this range of energies. On the other 

hand the Yb mode is clearly identifiable in the triple-filled

sample spectrum at about 5 meV. The La and Ba modes 

overlap significantly with the measured optical modes of

the skutterudite framework. In order to better reveal the 

filler modes, Fig. 3 shows ∆S(Q,E) differences between the 

partially filled skutterudites La0.2Co4Sb12, Yb0.2Co4Sb12, 

and Ba0.09La0.07Yb0.08Co4Sb12, and the host material 

CoSb3. Localized La and Yb modes are clearly identified

near 6 meV and 5 meV in La0.2Co4Sb12 and Yb0.2Co4Sb12, 

respectively, whereas for Ba0.09La0.07Yb0.08Co4Sb12 only the 

Yb mode is clearly visible. The La mode is much weaker 

because of its much smaller scattering cross section, and 

due to partial overlap with the Yb mode and with the 

host optical modes. The different types of filler atoms in

the triple-filled skutterudites also have different resonant

frequencies, further adding to the phase incoherence.

FIGURE 3: Difference functions ∆S(Q,E), relative to unfilled CoSb3, 

for Yb0.2Co4Sb12 (top), Ba0.09La0.07Yb0.08Co4Sb12 (middle), and 

La0.2Co4Sb12 (bottom).

The difference function DS(Q,E) for the partially filled

skutterudites varies as Q2 [2], indicating that cage fillers

in skutterudites with filling fractions up to ≈ 24 % are 

vibrationally phase incoherent, and that these materials 

are indeed akin to phonon glasses. Our neutron scattering 

measurements for partially filled skutterudites suggest that

there is a characteristic length L such that the vibrations 

of the guest atoms are largely phase-incoherent when the 

average nearest inter-filler distance is greater than L, and 

largely phase-coherent when that distance is less than L. In 

partially filled skutterudites, the filler-filler interaction is a

screened Coulomb interaction with an effective screening 

length of ≈ 12.6 Å, which corresponds to 29 % occupancy.

For smaller occupancies (inter-filler distances > 12.6 Å)

relatively weak interactions exist between fillers.

The multiple filler modes, discussed above, scatter a broad

range of acoustic phonons, resulting in very low values 

of kL. The lattice thermal conductivity kL may be written 

as k-ke, where k is the total thermal conductivity and ke is 

the electronic thermal conductivity; the latter quantity is 

obtained using ke = L0sT, where L0 is the Lorenz number

(approximately 2.0×10-8 V2/K2 in filled skutterudites),

s is the electrical conductivity, and T is the absolute 

temperature. Low temperature lattice conductivities are 

shown in Fig. 4. Partial filling of the voids, especially filling

with multiple types of atoms, transforms the thermal 

conductivity from crystal-like toward glass-like behavior. 

For multiple-filled skutterudites a broad peak is observed

above 30 K, which is totally unlike typical crystal behavior. 

The value of kL in multiple-filled skutterudites is roughly

2 W/m-K at room temperature, much less than that of the

unfilled skutterudite CoSb3. Above 700 K, kL is reduced 

to about 0.20 W/m-K, 7 times lower than for the Yb-filled

system and nearly 20 times lower than for CoSb3. As the 

temperature approaches 700 K kL becomes comparable with 

the theoretical minimum kmin.

Due to the combined effects of sufficiently random filler

distribution, phase-incoherent localized vibrations, and the

broad spectrum of guest resonant frequencies that leads to 

kL being ≈ kmin, we conclude that phonon-glass behavior is 

realized in multiple-filled skutterudites. Although singleand double-filled skutterudites exhibit similar random filler

distributions and incoherent filler rattling, their kL values 

are still higher than kmin at elevated temperatures.

The efficiency of thermoelectric materials is described by

the dimensionless figure of merit ZT = a2s T/k, where a is 

the thermopower. A very high ZT value of 1.7 at 850 K has 

been achieved due to the realization of kmin. This represents 

a more than 100 % improvement over current state-of-thepractice thermoelectric bulk materials. Such improvements

make these phonon-glass materials very attractive for 

power generation applications. 

References

[1] G. A. Slack, in CRC Handbook of Thermoelectrics, edited by D. M. 

Rowe (CRC, Boca Raton, FL, 1995), pp. 407.

[2] X. Shi, et al., submitted.

FIGURE 4: Low temperature lattice thermal conductivity for CoSb3-

based skutterudites.
36Soft Matter

36

Observation of thickness fluctuations in 

surfactant membranes

M. Nagao

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

Indiana University, Bloomington, IN 47408

Surfactant membranes are 

flexible objects with thermally

activated dynamics around room 

temperature. As shown schematically 

in Fig. 1, membrane dynamics 

has been investigated in terms of 

single surfactant molecular motion 

such as rotation, lateral diffusion, 

or vibration, and in terms of 

collective movements of surfactant 

molecules like bending, thickness, 

and protrusion fluctuations. The

bending motion, which is known 

to be observed at length scales 

larger than the membrane thickness, 

has been well described by the 

Helfrich bending energy [1], and 

many experimental investigations 

have been focused on understanding this motion. 

Helfrich proposed that the mechanical free energy 

functional of a membrane is increased by its 

resistance to bending, dH = κδC2/2, where k is the 

bending modulus and dC is a change in curvature. At 

length scales smaller than the membrane thickness, 

thickness fluctuations and protrusion motions

are expected to be relevant [2,3]. However, these 

dynamics are difficult to investigate experimentally

since the membrane thickness is too small to be 

accessed using visible light. It is known that when a 

film is very thin (less than 100 nm), the shapes of the

fluctuations in the two surfaces become correlated

and thickness fluctuations become important [4] and

hence are a relevant topic for the investigation of 

film dynamics [5]. In solutions, however, while there

has been related work, no detailed investigations 

of thickness fluctuations have been reported. Here

we highlight our recent work providing evidence 

of thickness fluctuations in a surfactant solution as

observed by neutron spin echo (NSE) [6]. NSE can 

probe membrane dynamics at length scales from 

below 1 nm to tens of nanometers and time scales 

ranging from a few ps to hundreds of ns.

A swollen lamellar structure composed of surfactant 

pentaethylene glycol dodecyl ether (C12E5), 

deuterated water (D2O), and an oil, deuterated 

octane (C8D18), was used as a model system. The volume 

fractions of C12E5, D2O, and C8D18 were fs = 0.041, fw =

0.9385, and fo = 0.0205, respectively. This sample contained

a small amount of oil, so that the C12E5 bilayers were 

slightly swollen by it and dispersed in D2O. Here, we call 

“membrane” the two C12E5 surfactant monolayers with the 

oil layer in between. The membrane thickness in this case 

can be calculated from the composition of the sample as dm

= 2(1+fo/fs)ds = 4.65 nm, where ds = 1.55 nm is the length

of the surfactant molecule. The temperature was kept at 

30 °C for small-angle neutron scattering (SANS) and 

29 °C for NSE with a temperature accuracy of ± 0.1 °C. At 

both temperatures the system is in the lamellar phase as 

confirmed by a SANS measurement.

FIGURE 1: Schematic model of dynamics of surfactant membranes. Depending on the 

length scale of the measurement, various motions may be observed: single molecular 

motions such as rotation, lateral diffusion and vertical vibration; collective motions such 

as, protrusion, stretching, and compression; and in thin films correlated motions of the 

top and bottom layer such as thickness and bending fluctuations.

FIGURE 2: SANS profile dS/dW(q) observed from the swollen lamellar 

sample at T = 30  ̊C together with the decay rate G observed by the 

NSE measurement at T = 29  ̊C. The inset gives a schematic idea of the 

structure of the system. The solid red line shows the result of the fit 

to a model scattering function of a lamellar structure, the solid blue 

line guides the eyes to show the G ~ q3 relation, and the dashed black 

line shows the peak position in G, which almost coincides with the dip 

position in the SANS profile.
NCNR 2010 Accomplishments and Opportunities 37

Shown in Fig. 2 is the SANS profile at T = 30

 ̊C. A correlation peak due to the stacking of

the lamellae is observed at q ≈ 0.09 nm-1 and 

the internal structure of the swollen lamellar 

membranes gives rise to another peak around q 

= 1.5 nm-1. The scattering profile is reproduced

using a model scattering function [7] as shown 

by the solid red line. The membrane thickness 

was estimated from the fit as dm = (4.7 ± 1.5) nm,

which is excellent agreement with the calculation 

from the sample composition. The inset in Fig. 2 

indicates the structure of the present system with 

the parameters estimated by SANS.

Figure 3 presents the intermediate scattering function, 

I(q,t)/I(q,0), showing the membrane dynamics measured 

by NSE spectroscopy. Solid lines in the figure indicate

fit results according to the single membrane fluctuation

model, a stretched exponential decay function given by 

I(q,t)/I(q,0) = exp[-(Gt)2/3], where G is the decay rate [8]. 

In this model, the decay rate Gb is expressed as [8], 

 , where g is a pre-factor 

originating from averaging the 

q vector, kBT the thermal energy, and h the solvent viscosity. 

Therefore, if the system shows only single membrane 

fluctuations, Gb should follow a q3 relation. However, as 

shown in Fig. 2, the q-dependence of G deviates from the 

q3 relation around the dip position in the SANS profile. In

addition to the bending mode, the present result shows 

that an excess motion appears near the length scale of 

the membrane thickness. Enhancement of the decay rate 

at length scales similar to the membrane thickness was 

first reported and related to the thickness fluctuations by

Farago and co-workers [9]. However, their work did not 

show a relationship between the bending and the thickness 

fluctuations.

So far, we do not have a good theory to analyze the NSE

data quantitatively. Thus we employ a phenomenological 

approach. Figure 3(b) shows the q variation of G/q3, which 

should be a constant for the case of pure bending motion. 

A clear peak-like behavior centered at q ≈ 1.2 nm-1 indicates 

that beyond bending there are also thickness fluctuations.

The data are well reproduced by the following relation: 

, where the first term corresponds

to the bending motion and 

the second term to the thickness fluctuations. The

q-dependence of the thickness fluctuations is expressed by

the Lorentz function in order to include a finite distribution

of the fluctuation lengths. The fitting parameters relate

to the physical characteristics of the motion as follows; A 

relates to the damping frequency of the motion, q0 is the 

momentum transfer value corresponding to the membrane 

thickness, and x gives an indication of the amplitude of 

the fluctuations. The best fit parameters are Gb/q3 = (19.7

± 0.8) x 10-21 m3/s, A = (89.0 ± 1.5) x 10-21 m3/s, q0 = (1.186

± 0.002) nm-1, and x = (5.13 ± 0.16) nm. The term Aq0

3

corresponds to the decay rate of the thickness fluctuations.

From the fits, Aq0

3 = (1.48 ± 0.03) x 108 s-1, which decreases 

with temperature (data not shown) and is close to the 

decay rate of the shape fluctuations in pentaethylene glycol

decyl ether, water, and octane droplet microemulsion [10]. 

This result suggests that the thickness fluctuations in the

swollen lamellar phase yield the shape fluctuations in

the droplet phase, which exists in the lower-temperature 

region. The estimated bending modulus k = (2.6 ± 0.1) kBT

is about twice that of C12E5 monolayers, indicating that the 

present membrane behaves like a C12E5 bilayer.

Figure 3(b) shows a clear deviation of the experimental 

data from the fit result at high q. Although the Lorentz

function employed here is rather phenomenological, the 

deviation shows a possibility of another intra-membrane 

dynamics, such as protrusion motion.

In summary, the membrane dynamics of a swollen 

lamellar phase was investigated using NSE. The surfactant 

bilayers are swollen by a small amount of oil, and 

thickness fluctuations are observed. The q dependence 

of the relaxation rate of the thickness fluctuations is

reproduced using a Lorentz function, and the relations

between fit and dynamical mode parameters are proposed.

At the length scale around the membrane thickness, the 

bending, thickness, and perhaps protrusion fluctuations

are observable by the NSE technique. It would be also 

possible to observe these modes in lipid vesicles containing 

membrane proteins and/or cholesterol. Such investigations 

will improve the understandings of membrane dynamics.

References

[1] W. Helfrich, Z. Naturforsch. C 28, 693 (1973).

[2] J. N. Israelachvili, H. Wennerström, Langmuir 6, 873 (1990).

[3] G. Brannigan, F. L. H. Brown, Biophys. J. 90, 1501 (2006).

[4] A. Vrij, J. Th. G. Overbeek, J. Am. Chem. Soc. 90, 3074 (1968).

[5] See the following review E. D. Manev, A. V. Nguyen, Adv. Coll. 

Int. Sci. 114-115, 133 (2005) and references therein.

[6] M. Nagao, Phys. Rev. E 80, 031606 (2009).

[7] J. Lemmich, K. Mortensen, J. H. Ipsen, T. Hønger, R. Bauer, O. 

G. Mouritsen, Phys. Rev. E 53, 5169 (1996).

[8] A. G. Zilman, R. Granek, Phys. Rev. Lett. 77, 4788 (1996).

[9] B. Farago, M. Monkenbusch, K. D. Goecking, D. Richter, J. S. 

Huang, Physica B 213&214, 712 (1995).

[10] T. Hellweg, D. Langevin, Phys. Rev. E 57, 6825 (1998).

FIGURE 3: Intermediate scattering function I(q,t)/I(q,0) observed by NSE and 

q-dependence of G/q3. 

 kBT 

1⁄2 

kBT Gb = 0.025g(––––)(––––)q3

 

k h

 A G/q3 = Gb/q3 + ––––––––––

 

1+(q–q0)2z2
38Soft Matter

38

Neutron transmission measurements of concentration 

profiles in non-homogeneous shear flows

M. E. Helgeson1, N. J. Wagner2, L. Porcar3

Many complex fluids exhibit non-homogeneousflows under certain conditions, in which the

flow field separates into regions of different local

deformation rate. For example, wormlike micelles 

(WLMs), comprised of long thread-like surfactant

aggregates, are a well-studied class of materials that 

exhibit this “shear banding” [1, 2]. These flows can be

accurately modeled using non-monotonic rheological 

constitutive relations between the local shear stress 

and shear rate [1-3], which are unstable between 

two critical shear rates g1c and g2c (Fig. 1, dotted 

line). Because these models qualitatively resemble 

thermodynamic phase separation, this has spurred 

debate as to whether or not inhomogeneous flow is

accompanied by macroscopic concentration gradients 

within the fluid. However, validation of this “flowconcentration coupling” has proven difficult because

no methods currently exist to make local composition 

measurements within the shear banded flow field.

Thus the direction, and even existence of, shearinduced concentration gradients remains a hotly 

contested theoretical problem.

We have recently devised a method to directly

measure the local concentration of fluids under shear

using neutron transmission profiling [4]. Because the

neutron attenuation is an absolute quantity, it can be 

generally applied to any fluid with sufficient neutron

contrast. To review, the neutron transmission, 

T, of a two-component fluid is given by

T = exp{–t[Dss12f + S’

a]} where t is the sample 

thickness, Dss12 is the difference in coherent crosssection between components 1 and 2, f is the volume 

fraction of component 2, and S’

a is the total incoherent 

cross-section. Thus, spatially-resolved transmission 

measurements enable direct determination of the 

concentration profile of material within the flow field.

In order to carry out these measurements, we use 

a recently developed Taylor Couette shear cell for 

small angle scattering measurements in the flowgradient shear plane (Fig. 2a). The cell is equipped 

with a translating slit aperture to allow for translation 

of the incident neutron beam across the Couette gap, 

yielding position-dependent scattering and transmission 

measurements [6]. Because the measured transmission 

can often be convoluted by forward scattering in ordinary 

SANS measurements, we have modified the experiments

to be compatible with ultra-small angle neutron scattering 

(USANS). The resulting technique, scanning narrow 

aperture flow-USANS (SNAFUSANS), yields accurate

transmission measurements with precise spatial resolution.

To test the existence of flow-concentration coupling,

we have made SNAFUSANS measurements on a 

model shear banding WLM fluid comprised of CTAB, a

cationic surfactant, in D2O near an equilibrium isotropicnematic phase boundary [3, 5]. Our previous flow-SANS

measurements have shown that shear banding in this 

system is due to a shear-induced, first-order phase

1Massachusetts Institute of Technology, Cambridge, MA 02139

2University of Delaware, Newark, DE 19716

3Institute Laue-Langevin, Grenoble, France

. .

FIGURE 1: Steady state rheology of shear banding CTAB wormlike 

micelles [3, 5]. Open circles: data, curves: model. Inset: velocity 

profiles vs. relative position (r/H) for region (II), g1c < g0 < g2c, are 

characteristic of shear banding. The data point colors and shapes 

correspond to points in the outer graph. Closed and open symbols 

represent points in the low-shear band (I) and high-shear band (III), 

respectively.

. . .
NCNR 2010 Accomplishments and Opportunities 39

FIGURE 2: (a) Schematic of the SNAFUSANS shear cell, indicating the 

incident beam direction relative to the beam slit (black). (b) Absolute 

neutron transmission (T) profiles for shear banding CTAB wormlike 

micelles confirm the existence of flow-concentration coupling. Insets 

show 2D SANS profiles for positions in the high-shear (paranematic) 

and low-shear (isotropic) bands.

transition to a highly-aligned paranematic state in the highshear band which coexists with a poorly-aligned isotropic 

state in the low-shear band [3, 5].

The measured transmission profiles for applied shear rates,

g0, spanning g1c and g2c and beyond confirm the existence

of flow-concentration coupling during shear banding

(Fig. 2b). For g0 < g1c the transmission profile, and thus the

surfactant concentration, is uniform with gap position, 

r/H, as expected for a homogeneously flowing fluid.

However, for g1c < g0 < g2c where shear banding occurs, 

the transmission exhibits a significant gradient, with T 

decreasing for points in the high-shear band and increasing 

for points in the low-shear band. Finally, a uniform 

transmission profile returns for g0 > g2c, where the fluid is

entirely paranematic in structure.

These results provide the first conclusive evidence for

flow-concentration coupling in a shear banding fluid.

Specifically, we find that the surfactant volume fraction

increases in the high-shear band at the expense of the 

low-shear band (Fig. 3), and at significantly high g0 reaches 

that required for the formation of a single nematic phase 

at rest, further confirming the mechanism previously

proposed for shear banding in the CTAB/D2O system [5]. 

Combination of this local composition information with 

local microstructure and flow kinematic data has allowed

for the construction of non-equilibrium phase diagrams, 

which serve as a quantitative “fingerprint” for the process

of shear banding as it relates to the thermodynamics of the 

fluid [4].

In conclusion, the SNAFUSANS technique demonstrates 

unparalleled ability to interrogate both the structure 

and composition of complex fluids under shear. This

initial study has, for the first time, confirmed flowconcentration coupling in a shear banding fluid, and

provides a complete data set with which to test emerging 

theories. More generally, the method should be readily 

applicable to the growing number of materials that exhibit 

non-homogeneous flow, enabling significant advances

in understanding the intricate relationships between 

composition, microstructure, and flow in complex fluids.

FIGURE 3: Measured CTAB volume fractions for the gap positions, 

r/H, indicated, indicating flow-concentration coupling during 

shear banding (shaded region). Solid and dashed lines give the 

concentration of the fluid at rest and that of an equilibrium nematic 

phase, respectively. Symbol colors correspond to the applied shear 

rates in previous figures.

References

[1] P. D. Olmsted, Rheologica Acta 47, 283 (2008).

[2] J. K. G. Dhont and W. J. Briels, Rheologica Acta 47, 257 (2008).

[3] M. E. Helgeson et al., Journal of Rheology 53, 727 (2009).

[4] M.E. Helgeson, L. Porcar, C. Lopez-Barron, and N.J. Wagner,

Phys. Rev. Lett. 105, 084501 (2010).

[5] M. E. Helgeson et al., Soft Matter 5, 3858 (2009).

[6] M. W. Liberatore et al., Physical Review E 73 (2006).

. . .

. .

..

. .

.
40Soft Matter

40

Mechanism of molecular exchange in 

copolymer dispersions

S-H Choi,1 T. P. Lodge1,2 and F. S. Bates1

Self-assembly of block copolymers provides considerable advantages over that of low 

molecular weight surfactants, including mechanical 

robustness, versatility in targeting media, and 

multiple functionality. The static structure and 

properties of block copolymer dispersions in aqueous 

and organic media has been extensively investigated 

[1]. However, much less attention has been paid to 

the kinetics of block copolymer dispersions, and 

particularly the mechanism governing molecular 

exchange between aggregates or micelles. The 

common difficulty in attaining equilibrium stems

from the strong incompatibility between the coreforming blocks and the solvent, coupled with the 

relatively large length of the core blocks. Potentially, 

molecular exchange kinetics, studied with suitably 

designed block copolymer solutions, can provide 

fundamental understanding on the time required 

for attainment of thermodynamically equilibrated 

structures.

In this highlight, we report the mechanism of single 

molecule exchange in block copolymer spherical 

micelles dispersed in oil, using the time-resolved 

small-angle neutron scattering (TR-SANS). In this 

model system, two pairs of structurally matched 

diblock copolymers of poly(styrene) (PS) and 

poly(ethylene-alt-propylene) (PEP) were prepared 

and designated PS-PEP-1 (<NPS> = 255 and <NPEP> 

= 978) and PS-PEP-2 (<NPS> = 412 and <NPEP> =

952), where the numbers denote the average number 

of repeat units. Each pair includes perdeuterated 

PS (dPS-PEP) and protonated PS (hPS-PEP). All 

four PS-PEP diblock copolymers form well-defined

spherical micelles with a PS core and a PEP corona 

when dispersed in squalane at lower concentration. 

The characteristics of the diblock copolymers 

and corresponding dispersions have been well 

documented elsewhere [2,3]. 

TR-SANS measurements were performed with 

the NG-7 30 m instrument at NIST, with a neutron 

wavelength of 7 Å. Specimens were prepared

by dispersing the copolymers in a mixture of 

perdeuterated and protonated squalane to contrast match a 

statistical 50:50 mixture of dPS and hPS in the micelle cores. 

Dispersions of pure hPS-PEP and dPS-PEP in the isotopic 

squalane mixture were blended to produce “postmixed” 

specimens, and stored at room temperature where the 

molecular exchange is completely suppressed due to the 

glassy PS core. Subsequently, the postmixed specimens 

were heated to a target temperature and monitored by 

SANS every 5 min (the experimental scheme is illustrated 

in Fig. 1). The SANS intensity is a proportional to the 

square of the core contrast (I(t)~[ρcore (t)–ρsolvent]1⁄2, where 

ρx is the scattering length density of x). The scattering 

length density of the cores in turn is directly related to the 

fraction of hPS (or dPS) chains in the cores, and is thus time 

dependent. Accordingly, the SANS intensity decreases 

with time as chains are exchanged, as shown in Fig. 2. The 

instantaneous state of exchange can be represented by the 

normalized relaxation function,

R(t) = {[I(t) – I(∞)]/[I(0) – I(∞)]}1⁄2, in which I(0) and I(∞) are

the scattering intensities at t = 0 and t → ∞. Consequently,

the values of R(t) are plotted versus a logarithmic time scale 

in Fig. 3. Consistent with results reported by Lund et al., 

R(t) is nearly linear on a logarithmic time scale, indicating a 

very broad distribution of characteristic times [4]. 

Since the results include two parameters (temperature 

and the core degree of polymerization Ncore), we applied 

the time-temperature superposition principle to account 

Department of Chemical Engineering and Materials Science1, and Department of Chemistry2, University of Minnesota, 

Minneapolis, MN 55455

FIGURE 1: Experimental scheme of time-resolved small-angle neutron 

scattering.
NCNR 2010 Accomplishments and Opportunities 41

FIGURE 2: Time dependence of SANS patterns obtained from a 1 % 

volume fraction dPS-PEP-2/hPS-PEP-2 50/50 mixture at 135 oC. Initial 

measurements were made at 30 oC (black filled circles) and followed 

by the acquisition of SANS data every 5 min (shown in the legend). 

for the effect of temperature based on the shift factors aT. 

Figure 4 illustrates that each set of data can be shifted onto 

individual master curves with a reference temperature Tref

of 125 oC. It is noteworthy that R(t) is strongly sensitive to 

Ncore, which is one crucial piece of evidence to resolve the 

exchange mechanism. 

We set up a kinetic model to explain experimental data

and details of the model has been documented elsewhere 

[2]; a brief summary follows. Merging and splitting 

of dispersions (also known as fusion/fission), one of

two primary mechanism in exchange kinetics, was not 

considered due to the concentration independence of 

R(t) observed at multiple concentrations. Single molecule 

exchange, the other primary mechanism, includes 

extraction of a core block, transportation through medium, 

and insertion into another micelle. Here, the extraction 

of the core block is assumed to be rate-limiting. When a

single molecule pulls out, the PS core block is governed 

by Rouse dynamics and must overcome the unfavorable 

interaction at the interface. Subsequently, the polydisperse 

FIGURE 3: Decay of reduced SANS intensity (normalized relaxation 

function) as a function of time for (a) dPS-PEP-1/hPS-PEP-1 at 100 oC 

(red circle), 110 oC (blue square), and 115 oC (cyan triangle) and (b) 

dPS-PEP-2/hPS-PEP-2 at 135 oC (green circle), 140 oC (gray square), 

and 145 oC (purple triangle). These results are nearly linear over the 

measurement range on a logarithmic time scale.

nature of the core blocks is considered. We observed

reasonable agreement between the experimental data 

and estimated R(t) by our model as illustrated in Fig. 4. 

Therefore, we propose that the exchange kinetics of block 

copolymer dispersions is governed by hypersensitivity 

to Ncore, therefore polydispersity, associated with the 

incompatibility between core forming blocks and media. 

FIGURE 4: Time-temperature superposed TR-SANS results with Tref

= 125 °C. Shift factors aT are shown in the inset. Master curves for 

chain exchange kinetics for PS-PEP-1 (unfilled, originally measured 

at 100 oC (blue), 110 oC (green), and 115 oC (red)) and PS-PEP-2 (filled, 

originally measured at 135 oC (blue), 140 oC (green), and 145 oC (red). 

Solid curves are best fit to our model. 

In conclusion, we have addressed the fundamental 

understanding of single molecular exchange kinetics in 

block copolymer dispersions using TR-SANS measurement. 

Good agreement between experimental data and our model 

provides key parameters controlling the single molecular 

exchange. This work also highlights the power of contrast 

matching technique in small-angle neutron scattering to 

investigate equilibrium kinetics without any additional 

chemical attachment but deuterium. 

References

[1] G. Riess, Prog. Polym. Sci. 28, 1107 (2003).

[2] S. Choi, F. S. Bates, T. P. Lodge, J. Phys. Chem. B 113, 13840 

(2009).

[3] S. Choi, T. P. Lodge, F. S. Bates, Phys. Rev. Lett. 104, 047802 

(2010).

[4] R. Lund, L. Willner, J. Stellbrink, P. Lindner, D. Richter, Phys.

Rev. Lett. 96, 068302 (2006).
42Soft Matter

42

How does ionic liquid distribute between microphaseseparated domains of a block copolymer?

J. M. Virgili, A. J. Nedoma, R. A. Segalman, and N. P. Balsara

Electrolytes based on mixtures of block copolymers and ionic liquids show promise 

in decoupling mechanical and ion-conducting 

properties critical for applications such as battery 

electrolytes and fuel cells. Block copolymers are 

made up of different kinds of polymers connected 

together (blocks). By carefully selecting the polymer 

blocks, copolymer materials can be engineered 

combining the properties of the individual blocks. 

The block copolymers in this work contain a polar 

block that is miscible, and a non-polar block that is 

immiscible, with the ionic liquid. The blocks have 

been chosen such that the miscible block favors 

ion transport while the immiscible block promotes 

mechanical stability. Knowledge of the distribution 

of ionic liquids in block copolymer microphases is 

crucial for application development because high 

concentrations of the ionic liquid in the non-polar 

microphases may decrease the efficiency of ion

transport and plasticize the microphases that are

intended to provide mechanical stability. 

The phase behavior of mixtures of an AB 

block copolymer with an ionic liquid has 

been studied previously in the dilute [1] and 

concentrated [2, 3] copolymer limits. These 

studies have revealed a selective solvent-like 

behavior of the ionic liquid, in which the 

higher solubility of the A block in ionic liquid 

compared to that of the B block results in the 

formation of micelles in the dilute copolymer 

limit and preferential swelling of the A 

microphases in the concentrated copolymer 

limit. While these studies have improved our

understanding of the phase behavior of AB 

block copolymer mixtures in an ionic liquid, 

quantitative characterization of the distribution

of ionic liquid between A and B copolymer 

microphases has yet to be established. Here 

we highlight our recent work using contrastmatching neutron scattering techniques to 

obtain a quantitative measure of ionic liquid 

distribution in these microphases [4].

We conducted small-angle neutron scattering

(SANS) experiments on the NG-7 instrument 

at the NCNR to characterize the distribution of ionic

liquid between copolymer domains. The block copolymer 

used was poly(styrene-block-2-vinylpyridine) (S2VP) and 

the ionic liquid was imidazolium bis(trifluoromethane)

sulfonimide ([Im][TFSI]). Both [hIm][TFSI] (h-liquid) and 

[dIm][TFSI] (d-liquid), where the prefix h or d indicates 

a protonated or deuterated imidazolium cation, were

utilized. We could also vary the deuterated fraction of

S2VP by using blends of S2VP in which the PS component 

was either deuterated (dPS) or protonated (hPS). fd is the 

deuterated fraction of such a copolymer blend before 

adding any ionic liquid. In the experiment h-liquid was 

mixed with a certain volume fraction of copolymer, 

φPOLYMER, and SANS measurements were made for various 

values of fd. 

An example is shown in Fig. 1a for φPOLYMER = 0.86 at

30 oC. The Bragg peaks correspond to a lamellar structure 

of liquid-rich polar P2VP microphase regions separated 

from liquid-poor non-polar PS microphase regions. Near 

University of California, Berkeley, Berkeley, CA 94720

FIGURE 1: (a) SANS intensity profiles (offset for clarity) for various 

values of deuterated copolymer volume fraction fd as a function of q for 

polymer volume fraction φPOLYMER = 0.86 mixtures in h-liquid at 30 oC. (b) 

Experimentally measured and modeled normalized peak intensities of the 

data in Fig. 1a as a function of fd. Inset shows detail near the contrast match 

composition. (c) Ionic liquid partition coefficient, γIL, for partitioning into PS 

blocks for varying copolymer to h-liquid and d-liquid mixture compositions as 

a function of copolymer volume fraction φPOLYMER.
NCNR 2010 Accomplishments and Opportunities 43

fd = 0.2 one can see that the major peak visible in all the

other curves disappears, rendering the lamellae invisible 

at the contrast-matching condition. In this way one can get 

a measure of the h-liquid concentration in the deuteriumcontaining PS microphase, because the scattering length 

density there now matches that in the liquid-swollen P2VP 

microphase regions. 

In order to extract the ionic liquid concentration in the PS 

microphase, the intensity of the major Bragg peak at q*, 

I(q*), must be modeled, making assumptions about the 

mixtures in the microphases. In effect, the models contain 

γIL, the ionic liquid microphase partition coefficient, as a

parameter. This parameter measures the fraction of ionic 

liquid in the PS microphase divided by the fraction of 

ionic liquid in the P2VP microphase. Fig. 1b plots the I(q*) 

normalized to the fd = 0 (undeuterated) value versus fd

for the case shown in Fig. 1a. The data are compared to 

the results of two model profiles, p1 and p2, which are 

described in detail in Ref. 4. Profile p1 assumes complete 

partitioning of ionic liquid into P2VP blocks with moderate 

mixing of PS and P2VP phases, while profile p2 results from 

the same degree of PS and P2VP mixing as p1, but some 

of the liquid is allowed to pervade the PS phase. Clearly, 

p1 gives the better fit, both to the value of fd and the peak 

intensity, as shown in detail in the inset to Fig. 1b. 

We repeated the experiment and analysis described above

for various φPOLYMER values, and also performed a similar 

experiment using d-liquid. The results are summarized

in Fig. 1c where we plot γIL versus φPOLYMER for both 

copolymer/h-liquid and copolymer/d-liquid mixtures. 

The analysis indicates that γIL for d-liquid ranges from 0 to 

0.67 while that of h-liquid is in the vicinity of 0 to 0.10. In 

spite of the large error bars, it is evident that γIL increases 

with increasing ionic liquid concentration in the case of 

d-liquid. The difference in partitioning of the deuterated 

and protonated ionic liquid in the PS- and P2VP-rich 

phases seen in Fig. 1c is unexpected. The error bars in Fig. 

1c mainly reflect our inability to ascertain the extent of

inter-mixing of the PS and P2VP chains under these 

scattering contrast conditions and the fact that the 

calculations are thus constrained to the h-liquid based 

values of 0 ≤ φPS, P2VP ≤ 0.15 and 0 ≤ φP2VP, PS ≤0.15, where

φPS, P2VP is the fraction of P2VP in the PS microphase and 

φP2VP, PS is the fraction of PS in the P2VP microphase.

The unexpected result for the difference in partitioning of 

the deuterated and protonated ionic liquid in the PS- and 

P2VP-rich phases seen in Fig. 1c prompted us to look for 

corroborating evidence. Glass transition temperatures 

of the PS-rich microphase (Tg,PS) were determined using 

differential scanning calorimetry (DSC) and are plotted 

in Fig. 2 as a function of the ionic liquid partitioning 

coefficient in the PS-rich microphase determined by SANS.

The error bars in Fig. 2 correspond to the range of γIL values 

shown in Fig. 1c. For the h-copolymer/h-liquid mixtures, 

Tg,PS is in the vicinity 100 oC, due to the near-complete 

partitioning of ionic liquid in the P2VP-rich microphase. 

In contrast, mixtures containing d-liquid exhibit a lower 

Tg,PS. This finding is consistent with the SANS data that

reveal a significant concentration of d-liquid in the PS-rich 

microphase. Based on measurements of the Flory-Huggins 

polymer-solvent interaction parameter, χ, of protonated 

versus deuterated polymers we anticipate variations of 

order 0.001 for χPS/P2VP caused by deuterium labeling. It is 

thus not surprising that deuteration of the copolymers has 

little effect on the glass transition temperature. Much less is 

known about the effect of deuteration on ionic interactions 

and hydrogen bonding, and hence what effect using 

deuterated ionic liquid has on thermodynamic properties. 

We have examined the distribution of an ionic liquid

within microphase-separated S2VP copolymer domains 

in concentrated mixtures of the two components. Using 

SANS contrast matching and DSC we established that the 

ionic liquid selectively partitions into P2VP domains for 

mixtures in the composition range 0.51 ≤ φPOLYMER ≤ 0.86.

The strong partitioning seen for h-liquid demonstrates the 

potential for block copolymer/ionic liquid electrolytes to 

allow the variation of mechanical properties necessary for 

real-world applications while maintaining the necessary 

ion-conducting properties.

References

[1] Y. Y. He, Z. B. Li, P. Simone, T. P. Lodge, J. Am. Chem. Soc. 128

(8), 2745 (2006).

[2] P. M. Simone, T. P. Lodge, Macromolecules 41 (5), 1753 (2008).

[3] J. M. Virgili, A. Hexemer, J. A. Pople, N. P. Balsara, R. A. 

Segalman, Macromolecules 42 (13), 4604 (2009).

[4] J. M. Virgili, A. J. Nedoma, R. A. Segalman, N. P. Balsara, 

Macromolecules 43 (8), 3750 (2010).

FIGURE 2: Glass transition temperature, Tg,PS, versus ionic liquid 

partition coefficient, γIL, for various copolymer/liquid mixture 

compositions and deuterium labeling. Error bars for γIL correspond 

to Fig. 1c.
Neutron Physics

Biology

44

Decoherence-free neutron interferometry

D. A. Pushin1, M. G. Huber2, M. Arif2, D. G. Cory1,3,4

Matter wave optics provides deep insights into 

quantum mechanics, and in particular matter 

wave interferometers have served as important 

examples of macroscopic quantum coherence. In 

general, matter wave interferometers are extremely 

sensitive to environmental noise such as mechanical 

vibrations, and as a result are not widely used. 

Just as the neutron interferometer assisted in the 

development of our current understanding of 

foundational issues in quantum mechanics, it is 

well suited to leading the practical implementation 

of improved coherent control using quantum 

information theory. Here we demonstrate how 

quantum error correcting codes may be used to 

improve experimental designs of quantum devices 

in order to achieve noise suppression. In particular, 

neutron interferometry is used as a testbed to show 

the potential for adding quantum error correction to 

quantum measurements.

A two-level quantum system is considered to be 

coherent if precise knowledge of the relative phase 

between the two basis states is obtainable. For 

measurements that involve averaging over multiple 

instances of the system, the phase for each element of 

the ensemble must be the same in order to maintain 

coherence. Dephasing occurs when a physical 

process causes the development of a random relative 

phase between the two basis states for each member 

of the ensemble.

In the case of a neutron interferometer, we are 

obtaining an expectation value measurement by 

averaging over many experiments consisting of 

interactions of individual neutrons with the device. 

The physical process leading to the development 

of the random relative phase for each neutron is 

mechanical vibrations. The two-level system is 

defined by the two possible paths a neutron can

take from the first blade of the interferometer to the

detectors (see Fig. 1b). Neutrons interact with the 

blades of the interferometer via Bragg scattering to 

produce two coherent beams of neutrons. The results 

of Bragg scattering may be modeled as a single 

neutron undergoing no interaction with the blade 

(transmission), or scattering (reflection), resulting

in a single component of the neutron’s momentum 

being inverted [1]. For a standard Mach- Zehnder (MZ)

interferometer (Fig. 1b) the middle blade serves as a mirror 

that redirects the two paths to a third blade where they 

recombine and interfere. For the 4-blade DecoherenceFree (DF) configuration (Fig. 1b), the situation is nearly

identical, except that the two paths are redirected twice 

with no mixing of states in the center of the interferometer. 

Mechanical vibrations may be considered as sinusoidal 

oscillations around the center of mass of the single crystal, 

which we write as ζ(t) = ζ0 sin(ωt + φ), where φ is a random 

phase that corresponds to a variation of neutron arriving 

times on the first blade. This variable can take any value

between 0 and 2π. For ζ we can specify any coordinates 

x, y, z, or any angles (such as θ - rotation around z axis). In

order to motivate the discussion we adopt a simple model 

for the neutron/blade interaction that includes all of the 

necessary physics [1]. Vibrations modify the velocity and 

path length of reflected neutrons relative to transmitted

1Massachusetts Institute of Technology, Cambridge, MA 02139

2Physics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899

3Perimeter Institute for Theoretical Physics, Waterloo, Ontario, Canada N2L 2Y5

4University of Waterloo, Ontario, Canada N2L 3G1

FIGURE 1: (a) A diagram of the 5-blade neutron interferometer. 

By moving cadmium shields up or down we can in situ select the 

three (MZ) or four (DF) blade interferometer configuration. (b) A 

schematic top-view representation of the five blade beam paths. The 

upper diagram represents the MZ setup. When we block the outer 

paths only we have the four blade (DF) setup, as shown in the lower 

diagram. (c) A schematic diagram of the neutron interferometer 

facilities at the NIST. This facility has several vibration isolation 

stages to remove vibrations above 1 Hz. To test the robustness of the 

interferometers to mechanical vibrations we introduced vibrations by 

a motor with an off-center mass attached to the table. We controlled 

the frequency of this noise through the speed of the motor. Vibrations 

were monitored by a seismometer [2].
NCNR 2010 Accomplishments and Opportunities 45

neutrons, introducing a relative phase difference between 

the two paths. For low frequency noise we may consider 

the interferometer as moving with a constant velocity for 

the time a neutron is in the device. For different arrival 

times of neutrons at the first blade, this velocity will be

different. Thus, the phase difference between the two 

paths will be randomly distributed based on the time of 

arrival. When averaging over multiple measurements,

we must average over the random phase, which leads 

to decoherence and a loss of contrast. The advantage of 

the DF interferometer is that these phases will be much 

smaller, with significantly less variance than for the MZ

interferometer.

The interferometer contrast is a measure of interferometer 

quality and is ≤ 1. Figure 2 represents numerical

simulations of changes in the interferometer contrast 

due to vibrations along x and y axes and rotational 

vibrations about z [1]. From these numerical simulations 

we can see that 4-blade (DF) design is far less sensitive 

to low frequency vibrations. Thus a solution to robust 

interferometry could be based on a four-blade single-crystal 

geometry that reduces errors introduced by vibrations.

In order to test our idea and compare MZ and DF

designs we built a five blade neutron interferometer that

incorporates both a standard Mach-Zender configuration

and a decoherence-free configuration based on a

decoherence-free subspace (DFS) [2]. The switch between 

designs occurs in situ by moving cadmium (Cd) beam 

blocks. In Fig. 3a we show a drawing of the five blade

interferometer used in this study. It was cut out of a single 

crystal Si ingot at the University of Missouri machine shop. 

The incoming neutron beam coherently splits at the blades 

by Bragg scattering. In order to preserve crystallographic 

registration of the blades each blade remains attached to 

the common base. 

As shown in Fig. 1, the neutron beam enters the single 

crystal interferometer from the left and is split coherently 

by the first blade over two paths. Blades 2, 3, and 4 direct

the beams through four different paths and recombine 

them at the last (fifth) blade. Interference of these paths is

observed by 3He detectors placed in the O- and H-beams. 

As shown in Fig. 1b, by placing Cd blocks we can choose 

either the MZ (3-blade, upper schematic diagram) or DF

(4-blade, lower diagram) setups.

Figure 1c outlines the experimental setup of the Neutron 

Interferometer and Optic Facilities at the National 

Institute of Standards and Technology, Gaithersburg, 

MD. The interferometer is placed inside an enclosure 

with a temperature stability of a few mK to maintain its 

phase stability [3]. The enclosure is isolated from external 

vibrations by a high position stability (< 1μm) vibration 

isolation system. We add controlled vibrations to the

system through a motor with an off-center shaft. Vibrations 

were monitored by a short-period seismometer.

To measure the contrast we introduce a phase difference 

between the two interferometer paths and measure the 

phase dependence on the output intensity at both the Oand H- beams. In neutron interferometry it is convenient 

to introduce this phase difference through a fused silica 

phase flag placed between the first and the second blades

(see Fig. 1a). Figure 3a shows the intensity dependence for 

the 3-blade (MZ) configuration with and without added

noise. The vibrations were artificially introduced with a

fundamental frequency of 8 Hz. Without vibrations the

interferometer has a 12 % contrast while with vibrations 

there is no detectable contrast.

Figure 3b shows the contrast for the four blade (DF) 

interferometer under the same conditions used for the 

three blade MZ setup [2]. Here there is no measurable

loss of contrast with added noise. As expected, the DF 

configuration is substantially more robust to the applied

noise than is the MZ configuration [1].

Experiments verify that the decoherence-free 

interferometer is protected against low frequency 

mechanical vibrations that significantly degrade the

performance of the standard design. We anticipate that

these improvements will increase the range of applications 

for matter wave interferometry, such as in soft condensed 

matter and spintronics. 

References

[1] D. A. Pushin, M. Arif, and D. G. Cory, Phys. Rev. A 79, 053635 

(2009).

[2] D. A. Pushin, M. G. Huber, M. Arif, and D. G. Cory, 

(submitted) 

[3] D. A. Pushin, M. Arif, M. G. Huber, and D. G. Cory, Phys. Rev. 

Lett. 100, 250404 (2008).

FIGURE 2: Calculation of contrast change due to applied vibrations for 

3-blade (MZ) and 4-blade (DF) interferometers show on Fig. 1b. From 

the left: vibrations along the y-axis, the x-axis, and due to rotational 

vibrations around z-axis and the center of mass. Note that the scale 

of the frequency for rotational vibrations is a factor of 10 lower than 

those shown for vibrations along the y- and x-axes [1].

FIGURE 3: (a) Interferograms from the three blade (MZ) 

interferometer without vibrations (open circles) and with 8 Hz 

vibrations (closed circles). We observe a complete loss of contrast 

with 8 Hz vibrations. (b) Interferograms from the four blade (DF) 

setup at the same conditions as in 3a. Within experimental errors 

there is no loss of contrast from the added vibrations.
Advances in Measurement

46

Software for biological soft condensed matter science

J. E. Curtis and S. Krueger

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

Proteins, nucleic acids, and lipids are the key 

components that carry out the structural and 

catalytic roles enabling complex biological systems to 

function. Atomic level structural knowledge of such 

systems has relied upon x-ray diffraction and nuclear 

magnetic resonance (NMR) spectroscopy. Increasingly, 

the biological research community acknowledges that 

understanding the structure of homogeneous and 

heterogeneous protein, protein-nucleic acid complexes 

in solution and on lipid membranes is an important 

problem that is not generally accessible using x-ray 

diffraction or NMR. Many of these systems have 

unstructured or disordered regions that have important 

functional roles that complicate the interpretation of 

experimental data.

We are developing software for the NCNR user

community to aid the design and interpretation of 

neutron scattering data for biological soft condensed 

matter systems. The software aims to lower the barrier 

experienced by non-experts to handle the technical 

details (coordinates, force-fields) of manipulating

atomic information and to accurately calculate neutron 

observables that can be compared to experimental 

data. The platform-independent open-source software 

is designed such that the atomic coordinates are 

accessible by other state of the art molecular dynamics 

and molecular modeling software suites. We have

condensed the modeling, structure generation, and 

analysis algorithms into a software suite called SASSIE. 

The development of the software has been guided 

by a variety of collaborative research projects with 

NCNR users. We have used the software to design

and interpret various small-angle neutron (SANS) and 

neutron reflectivity (NR) experiments of homogeneous

and heterogeneous biological systems [1, 2].

As an example, in collaboration with scientists from 

the Center for Advanced Research in Biotechnology 

(CARB), we have used SASSIE to model the structure 

of the Methanobacterium thermoautotrophicum (mtMCM) 

minichromosome maintenance protein complex in 

solution. The mechanism of DNA unwinding during 

the replication process is not completely understood. 

However, it is thought that the flexible domains

present in the mtMCM play an important role. While

some partial x-ray crystal structures are available and 

cryo-EM has provided several different structures 

of the full protein, no solution structures have been 

reported. Figure 1 shows the SANS data obtained for 

the N-terminal portion of mtMCM in solution. A family of 

structures that best fit the SANS data was found by using

SASSIE to explore the range of possible conformations of 

the flexible regions of the protein and then comparing the

resultant structures to the SANS data. These structures will be 

compared to those obtained from mtMCM with DNA bound 

in order to ascertain if there are inherent structural differences 

between mtMCM with and without DNA. If so, then these 

differences could be important in ascertaining the mechanism 

of DNA unwinding during DNA replication.

In summary, we have developed open-source software to aid 

in the design and analysis of neutron scattering experiments 

of complex biological systems. The software is available to the 

scientific community at (www.smallangles.net).

FIGURE 1: Determination of the structure of MCM helicase. SANS 

data for mtMCM in solution are shown along with the model SANS 

curve for one of these structures (solid red line). The family of best-fit 

structures, depicted as a density plot of configuration space, is shown 

in the inset. The yellow area maps out the space that is occupied by 

one of the flexible regions in the protein while the magenta area 

represents the space occupied by the other flexible region. The 

blue and green areas, barely seen in the figure, represent the static 

regions of the protein.

References

[1] S. A. K. Datta, et al., J. Mol. Bio. 365, 812 (2007), D. Lee, et al., 

Mol. Cell, 22, 423 (2006), J. VanOudenhove et al., J. Mol. Bio. 387, 

910 (2009).

[2] H. Nanda et al., Biophys. J (in press), M. S. Kent et al. Biophys. 

J (in press), J. E. Curtis and S. Krueger, Chem. Phys. Comm. 

(submitted), H. Nanda et al. J. Mol. Bio. (submitted).
NCNR 2010 Accomplishments and Opportunities 47

Following lithium through battery components 

and functioning prototypes

H. Wang1 and R. G. Downing2

1State University of New York, Binghamton, NY 13902 

2Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899

Energy storage systems such as batteries play an increasingly significant role in our daily routine as they

power personal electronics, tools, and a variety of vehicles. 

Longer lasting and more powerful batteries are in ever greater 

demand in today’s mobile society. Companies, universities 

and federal laboratories are using NIST facilities to develop 

powerful and longer lasting lithium ion batteries. Neutron 

Depth Profiling (NDP) is a nondestructive analytical technique

used to determine the quantity and the depth distribution of 

lithium, as well as several additional elements in solid films

(Fig. 1). It is among the effective neutron techniques that 

give researchers a faster and clearer perception of lithium’s 

behavior in existing and new battery designs. 

FIGURE 1: In NDP, as the nuclear decay particles course through the 

sample they lose energy by collisions, giving a measure of the depth 

below the surface from which they originated.

Lithium ion batteries permanently lose a significant portion

of the electrical storage capacity upon first use and sustain

incremental losses in each subsequent charge-discharge cycle. 

So where is the unavailable lithium and why does it stop 

contributing to the available energy? An NDP analysis locates 

the total lithium inventory and its distribution across the entire 

battery thickness. Furthermore, since the NDP technique is 

nondestructive; analyses are conducted on a fully functioning 

battery. Neutrons are electrically neutral particles that flow

through the sample and react with a small number of lithium 

atoms to produce energetic alpha and triton particles. As 

those particles emerge from all depths of the cell the number 

of particles of a given energy define both the Li atom density

and the depth of origin across the cell. The battery remains 

undisturbed in the instrument over multiple charge-discharge 

cycles while cold neutrons flow through the cell generating the

NDP signal. Researchers observe the migration of the lithium 

as devices age through repeated charge and discharge cycle. 

The “frozen” lithium is eventually spotted.

Migration of lithium is shown through a time series of 

NDP measurements in Fig. 2. The top group shows 5 NDP 

individual spectra taken during the charge cycle of a thin 

film lithium ion battery. Lithium ions are shown migrating

from the LiCoO2 cathode (decreasing in Li content at the high 

energy plateau) to the Li metal anode (increasing in lithium 

content at the low energy peaks) through a LiPON electrolyte 

(relatively invariant at the intermediate energy). As expected, 

when the battery is discharged, the anode gives up Li ions 

that migrate back to the cathode (lower group of spectra). The 

NDP spectra capture the systematic drop in Li atom density 

from the anode and the gain of Li at the cathode. This process 

has been repeated under different conditions and for extended 

charge-discharge cycles. In summary, NDP that allows chargedischarge cycles to be followed systematically and the lithium 

quantified without destroying the cells or exposing the airsensitive lithium to the atmosphere is a powerful tool in the 

quest for long-lived lithium batteries.

FIGURE 2: NDP spectra of the lithium distribution in a thin film 

battery. (The discharge spectra are displaced 500 units.) The large 

arrows depict the time sequence of Li depth profiles captured as 

the battery is charged and discharged. The inset diagrams illustrate 

the lithium ion and electron flow and battery composition and 

construction. Below, the colored strip shows the approximate 

positions of the battery components.
Advances in Measurement

48

Peering inside: imaging an object’s interior 

while clarifying its elemental makeup

R. Bindel1, E. Korobkina2, T. Mahale3

1Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899

2North Carolina State University, Raleigh, NC 27606

3Telos Medtech LLC, Raleigh, NC 27606

Somewhere between prompt gamma activation 

analysis (PGAA) and neutron imaging, a hybrid 

tool dubbed “scanning PGAA” produces images of 

a sample’s interior structure while elucidating its 

elemental composition. This technology is uniquely 

positioned to evaluate new materials, particularly 

those for which non-destructive analyses are needed. 

Recently, 3D fabrication techniques capable of complex 

freeform geometries have been of increasing interest 

to the medical community as a way of producing 

customized bone replacement implants out of titanium

alloys. However, there is uncertainty in the homogeneity 

of the alloy within samples produced by such processes, 

and this is unacceptable for medical purposes. Scanning 

PGAA was used to look at an interior cross section of a 

non-stochastic foam made of a Ti-6Al-4V. The feasibility 

of examining the spatial homogeneity of the alloy was 

assessed.

The instrument configuration for scanning PGAA is

similar to the typical PGAA setup. PGAA is a tool for 

measuring the presence and amount of many different 

elements, but it has no inherent imaging ability. In the 

usual arrangement at the NG-7 beam guide, a sample 

is placed in a uniform, collimated neutron beam. A 

shielded gamma-ray spectrometer views the sample 

through a long lead collimator perpendicular to the 

neutron beam. In the scanning PGAA configuration, the

neutron beam is focused using a polycapillary neutron 

optic [1], and the field of view of the spectrometer is

reduced to a few millimeters before and after the focal 

spot. A system of precision stages is used to move the 

sample in a raster pattern through the neutron beam to 

produce a multidimensional image. 

The sample was manufactured using an Electron Beam 

Melting (EBM) process in which 2D layers of powdered 

Ti-6Al-4V are sequentially melted to produce a 3D part. 

This layered approach is capable of producing complex 

geometries; however, the powdered starting material is 

recycled between layers, possibly exacerbating the buildup of 

contaminants or fractionated evaporation and deposition of 

the constituent elements.

Figure 1 presents photographs of the sample with the location 

of the cross-sectional slice superimposed. Figure 2 shows a 

map representing the intensity of the titanium signal at 1381 

keV, where a PGAA spectrum was acquired for 10 s at each 

pixel. Figure 3 shows a PGAA spectrum obtained over a 90 

minute period at just one position. In this spectrum, the weak 

aluminum and vanadium peaks can be quantified. Using

multiple long acquisitions at different spots, homogeneity of 

the titanium alloy sample can be assessed. The combination of 

imaging along with the multi-element analytical properties of 

PGAA make scanning PGAA a good candidate for examining 

the homogeneity of Ti-6Al-4V forms produced with additive 

manufacturing techniques.

Reference

H. H. Chen-Mayer, D. F. R. Mildner, V. A. Sharov, Q. F. Xiao, Y. T.

Cheng, R. M. Lindstrom, R. L. Paul, Rev. Sci. Instrum. 658 (10), 

3744 (1997).

FIGURE 1: The sample from two perspectives. The position of 

the slice imaged by scanning PGAA is superimposed in blue.

FIGURE 2: An interior cross-sectional image produced by mapping 

the intensity of the titanium peak at 1381 keV.

FIGURE 3: 

A long 

PGAA count 

at a single 

location 

featuring 

titanium, 

aluminum, 

and 

vanadium 

peaks.
NCNR 2010 Accomplishments and Opportunities 49

Time-resolved SANS with sub-millisecond resolution 

(t-SANS)

C.J. Glinka1,2, J.G. Barker1, J. Moyer1, N. Maliszewskyj1, P. Tsai1, X. Wang3, A. Wiedenmann4

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

2University of Delaware, Newark, DE 19716

3Brown University, Providence, RI 02912

4Institut Laue-Langevin, 38042 Grenoble Cedex 9, France

Changes in nanoscale structure that occur on time scales 

in the micro- to millisecond regime in response to some 

stimulus are critical to the function and performance of materials 

as varied as muscle tissue, membranes, superconductors, 

‘smart’ gels, electrorheological fluids, domains in ferroelectrics

and ferromagnets, and photosensitive macromolecules. Using 

neutrons to probe this time regime has been difficult for intensity

reasons but has recently become more viable due to the successful 

demonstration [1] of a novel technique proposed a decade ago 

by Gähler [2]. Now the first permanent installation of equipment

enabling the technique has been completed at the NG-7 30 m 

SANS instrument. The capability provided to follow changes in 

nanostructure and macromolecular conformations on relevant 

time scales is expected to have a major impact on materials and 

biological research at the NCNR.

The main modification to the NG-7 SANS instrument to

implement Gähler’s technique has been the incorporation of a 

high speed disk chopper within the initial collimation section of 

the instrument, some 15 m from the sample position. The 10 μs 

to 20 μs neutron pulses from the chopper have a broad band of 

wavelengths (10 % < ∆l/l < 30 % depending on the setting of the 

instrument’s upstream velocity selector) and thus spread in time 

with several pulses overlapping when they reach the sample. This 

so-called frame overlap is normally to be avoided in time-of-flight

measurements, but here is essential to the intensity gain inherent 

in Gähler’s technique. With the proper choice of neutron pulsing

frequency, depending on the given sample stimulus frequency 

and sample-to-detector distance, neutrons from multiple pulses 

that scattered at equivalent times, relative to the sample stimulus 

period, arrive at the detector at the same time. With this technique,

which we refer to as t-SANS, the effective duty cycle of the 

measurements is typically ≈10 % rather than 1 % to 2 %, which is

what it would be if the pulses had to be spread far enough apart to 

avoid any frame overlap. A time-distance diagram illustrating the 

principle of the technique is shown in Fig. 1. 

To demonstrate the technique, t-SANS measurements have 

been made on a rapidly-solidified amorphous Fe (with 4 % Si)

sample as a function of the frequency of an applied sinusoidal 

magnetic field. The scattering is isotropic in zero field and

increases perpendicular to an applied field, presumably due to

the alignment of magnetic precipitates along the field direction.

The orientational response of the precipitates is what is directly 

probed with t-SANS. Shown in Fig. 2 is the ratio of the scattering 

perpendicular and parallel to a sinusoidal field of with amplitude

0.011 T and a frequency of 1560 Hz. For the conditions of this

measurement the calculated time resolution is 60 μs full width at 

half maximum which is more than adequate to confirm that the

precipitates align along the field with little or no phase lag at this

frequency.

With the apparatus installed on the NG-7 SANS changes in

nanostructure that occur in as little as 30 μs in response to a 

periodic stimulus can be detected and characterized. This

capability is expected to greatly expand the scope of SANS 

studies on a wide range of materials.

References

[1] A. Wiedenmann, U. Keiderling, K. Habicht, M. Russina,

R. Gähler, Phys. Rev. Lett. 97, 057202 (2006).

[2] D. Kipping, R. Gähler, K. Habicht, Physics Letters A 372, 1541 

(2008). Gähler’s acronym for the technique described herein is 

TISANE.

FIGURE 1: A time-distance diagram showing the trajectories of 

neutrons from successive chopper openings (C) resulting in frame 

overlap at the sample (S). Neutrons from different chopper pulses 

which probe the same oscillation state are observed at the same time 

equivalent channel at the detector (D), if the equations in the diagram 

are satisfied. 

FIGURE 2: The integrated SANS (0.008 Å-1 < Q < 0.033 Å-1) parallel 

and perpendicular to a time varying magnetic field (solid line). These 

data show that the magnetic moments in the sample are able to 

follow the field reversals at this frequency. 
Advances in Measurement

50

Elemental analysis of a single-wall carbon nanotube

candidate reference material

R. Zeisler1, R. L. Paul1, R. O. Spatz1, L. L. Yu1, J. L. Mann1, W.R. Kelly1, S. D. Leigh2, and J. Fagan3

1Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899

2Statistical Engineering Division , National Institute for Standards and Technology, Gaithersburg, MD 20899

3Polymers Division, National Institute for Standards and Technology, Gaithersburg, MD 20899

Carbon nanotubes (CNTs) are one of the first

major nanoscale manufactured products to enter 

the market. Reliable and reproducible quantitative 

measurement and characterization of CNT samples is

important not only for progress in the understanding 

and development of new applications incorporating 

these materials, but also for the development 

of an information base for CNT toxicology. The 

characterization of CNTs containing residual

catalyst and impurity metals represents a broad 

analytical challenge. The metals may be present 

as major constituents or at trace and ultra-trace 

levels, and may be loosely adducted to the matrix, 

firmly incorporated, or chemically bound. Common

analytical techniques such as inductively coupled 

plasma optical emission or mass spectrometry (ICPOES or ICP-MS) may be hampered by problems if 

nanoparticle-containing solutions are introduced 

directly into the plasma or if sample digestion 

is incomplete. Additionally, the need for sample 

dilution becomes an issue with only small amounts 

of CNT material available for analysis. Similar 

limitations exist for x-ray fluorescence spectrometry

(XRF), which may not have the sensitivity to analyze

small CNT amounts in dispersions or in bulk 

samples. 

In response to the need for reliable measurement 

of CNTs, NIST has developed a single-wall CNT 

(SWCNT) reference material,

Standard Reference Material (SRM) 

2483 Carbon Nanotube Soot. This 

SRM, which contains SWCNTs

together with other carbon species, 

catalyst residues, and trace element 

contaminants, has been characterized

by a combination of neutron 

activation analysis (NAA) and 

inductively coupled plasma mass 

spectrometry (ICP-MS). Instrumental 

neutron activation analysis (INAA) 

was carried out on 25 mg to 40 mg 

samples of the SRM. Prompt gammaray activation analysis (PGAA ) was 

performed on approximately 100 mg 

samples using both the NIST thermal 

and 

cold neutron PGAA spectrometers. Both methods are 

fully instrumental and require no sample dissolution. All 

measurements were carried out using pure elements or 

compounds as standards and appropriate control materials. 

ICP-MS measurements were performed on 25 mg to 160 mg 

samples of the SRM following Carius Tube digestion in 

hydrochloric and nitric acids. Calibration was performed 

using NIST single element spectrometric solutions.

PGAA, INAA, and ICP-MS procedures complemented 

each other in elemental coverage and provided 

independent results for the catalyst elements and some 

trace contaminants. These results were combined to assign 

mass fraction values for the Certificate of Analysis (COA).

Table 1 lists the measurement results together with the 

proposed certified values and their statistically evaluated

uncertainties for the COA. 

NAA procedures were found to be well-suited for the 

characterization of the SWCNT materials because of their

extensive dynamic range. Percent level elements were 

determined in the same test portions as the trace elements. 

PGAA provided results for CNT matrix elements such as 

hydrogen and carbon, the catalyst residue elements and 

some trace elements. ICP-MS provided results chiefly

for the rare earth elements allowing for the first time the

assignment of certified values for this group. This work

demonstrated that analysts may find in the characterization

of CNT materials a new domain for NAA applications.

Table 1. Measurement and certified values reported for SRM 2483.

Element /

Nuclide

INAA PGAA ICP-MS Certificate 

Value

Average (SD)

n = 44

Average (SD) 

n = 10

Average (SD) 

n=9

Value (U)

k=2

Ba mg/kg 120.2 (9.6) 116.6 (2.5) 118.4 (3.6)

Ce mg/kg 189 (17) 196.3 (2.3) 192.6 (5.4)

Cl mg/kg 2080 (74) 2170 (40) 2125 (54)

Co % 0.954 (0.028) 0.971 (0.012) 0.963 (0.011)

Dy mg/kg 8.44 (0.31) 8.27 (0.07) 8.36 (0.13)

Eu mg/kg 2.34 (0.18) 2.207 (0.020) 2.274 (0.084)

Gd mg/kg 10.05 (0.11) 11.05 (0.09) 10.58 (0.56)

La mg/kg 102.2 (3.0) 106.2 (1.2) 104.2 (2.7)

Mo % 3.39 (0.11) 3.42 (0.05) 3.406 (0.029)

Sm mg/kg 12.36 (0.39) 13.86 (0.15) 13.00 (1.5) 13.09 (0.90)
NCNR 2010 Accomplishments and Opportunities 51

Neutron Source Operations

The NIST reactor (NBSR) operated for 267 full power (20 

MW) days or a 99 % availability during FY10. A typical

operational year consists of seven cycles of approximately 

38 days followed by 11 days of shutdown maintenance and 

refueling activities. The shutdown periods are carefully 

scheduled and choreographed by the Reactor Operations 

and Engineering (ROE) Group to assure the maximum 

preventative and corrective maintenance is efficiently

performed during this limited time. The ROE routine 

maintenance program is a significant contributor to the

outstanding record of safe and reliable NBSR operation. 

FIGURE 1: Senior Reactor Operators Paul Bobik and Jim Moody add 

new fuel to the NBSR during a routine maintenance shutdown.

Beyond routine and corrective maintenance activities, 

much of the ROE staff efforts this past year involved 

a coordinated NBSR Age Management program that 

focused on the replacement or upgrade of systems nearing 

the end of their useful lifetime. Planning for these large 

projects began several years ago and the opportunity of 

an extended facility shutdown in 2011 will allow several 

essential NBSR systems to be upgraded or replaced. 

The NBSR power level is controlled by four neutron 

absorbing shim arms that must be replaced approximately 

every four years. Over this reporting year, the ROE Group 

contracted for the design and manufacture of a replacement 

set of shim arms. Following the receipt of a first set to

qualify the shim arm manufacturing process, the NCNR 

will purchase sufficient spares to last well past the current

license expiration date of July 2029. New technology was 

utilized to manufacture the new shim arms and a prototype

was received in August for inspection by the ROE Group.

Sean O’Kelly has now become the Chief of the ROE Group 

following the retirement of Wade Richards and a Quality

Engineer, Bill Schuster, was hired to provide configuration

management oversight. Finally, two new senior reactor 

operator licenses were received by Andrew Blazek and Jeff

Burmeister. 

FIGURE 2: Senior Reactor Operators Bill Mueller and Jeff Burmeister 

remove prototype NBSR shim arm for examination.
52Expansion Initiative

Expansion Initiative

The NCNR is now midway through an Expansion Initiative to increase its cold neutron 

measurement capability by more than 25 percent 

by installing a new cold source and new beamlines, 

and set the foundation for a new generation of 

world-class instruments directly supporting the 

needs of science and industry. The Initiative is a 

complex multi-year project that includes the coordination of civil 

construction works for 

new buildings to house 

the expanded instrument 

suite in addition to 

refurbishment projects 

for facility improvements 

to the neutron source. 

The Initiative is 

proceeding on a schedule 

that will require a 101⁄2

month shutdown of 

the reactor beginning 

in April 2011. During 

this outage period new 

cold neutron guides will be run from the reactor 

confinement building in readiness to serve new and

relocated instrumentation in the expanded guide 

hall. And over the past year the Facility’s engineering 

and technical staff have been working hard to reach a series 

of major milestones required for the outage and this first

phase of installation work.

Civil Construction

Construction work on the guide hall addition and new 

technical services and administrative building (TSB) is now 

complete (Fig. 1). The guide hall extension provides an 

additional 16,000 sq ft to the 20,000 sq ft area of the current 

building for the new guides, shielding and instrumentation 

envisaged through the Initiative. The two-story TSB will 

house the Facility User Office and includes shop space and

a conference facility along with some 

40 new offices. Staff began moving into

this new accommodation during the 

summer of 2010. The availability of 

new office space is a key component in

the ongoing program to improve and 

renovate the NCNR laboratories used 

by both visitors and staff, enabling a 

number of the rooms vacated to be 

refurbished and returned to laboratory 

space as originally purposed. A 

second 18 month construction phase is 

scheduled for the autumn of 2010 and 

will deliver new buildings to house 

support infrastructure for the neutron 

source and, during the outage period, 

core bore holes from the confinement

building through to the guide hall, 

FIGURE 1: Panoramic view showing the completed TSB (foreground, left side,) with a new walkway 

connecting to the guide hall in the back. The guide hall extension (slightly different wall pattern) can be 

seen on the right-hand side.

FIGURE 2: – Inside the recently completed guide hall extension. As part of the second 

construction phase, the dividing wall (shown on the left) between the existing guide 

hall and the extension will be removed.
NCNR 2010 Accomplishments and Opportunities 53

marking the start of the guide installation 

program. 

Outage activities: Guide and shielding 

installation

The central tenet of the Expansion Initiative is 

the installation of five new supermirror guides

(outlined below) to service new and re-located 

cold-neutron instruments in the guide hall 

extension. The MACS spectrometer will be 

relocated to a new cold source at BT-9, thereby 

opening a viewport on the current facility 

cold source to accommodate the new guides. 

During the reactor outage period the first stage

of a carefully choreographed and multi-phase 

installation sequence begins with the installation 

of new guide sections running from the reactor 

confinement building and through the D-wing

(Fig. 2). All guide components for this first phase

have been delivered and are undergoing characterization

and pre-alignment. Staff members have also been working 

to complete the huge inventory of engineered ancillary 

components required to install the guides including 

main shutters, shielding, and vacuum jackets. Close to 

the reactor face the guides are housed in large monolith 

assemblies and detailed installation sequences have been 

established to guarantee that there is clearance to maneuver 

the assemblies in place and also to ensure appropriate 

access to re-check guide alignment. 

Guide Specifications

The new guides utilize the latest in supermirror coating

technology, yet must conform to existing installations and 

have only a restricted viewing angle of the cold source. 

Extracting five new beams presented an engineering and

neutronics design challenge solved through judicious use 

of curved sections close to the source followed by straight 

sections:

NG-A – is a 41 m long guide earmarked for the Neutron 

Spin Echo instrument. To restrict beam divergence lower 

critical angle, high reflectivity coatings are used on the

straight portions and inner radii of the guides.

NG-B – is also a low divergence guide for use by small 

angle neutron scattering (SANS) instruments. At a 

distance of just under a meter from the cold source, the 

guide divides into discrete upper (48 m long) and lower 

(52 m long) sections designed for 30 m and 10 m SANS 

instruments, respectively.

NG-C – is also a high-flux high reflectivity

guide and will service a “reflectometer

village” comprising the current vertical 

polarized beam reflectometer plus the

new instruments MAGIk and CANDoR. 

The end station of NG-D will be the new 

location for the chemistry Prompt Gamma 

Activation Analysis and Neutron Depth 

Profiling stations.

Second cold source installation

The displacement of MACS has 

necessitated the design and building of 

a second cold source dedicated to the 

instrument. The new ‘PeeWee’ source

has disk geometry, optimized for MACS

subject to the geometric constraints 

imposed at BT-9 (Fig. 5), and will provide 

a factor two gain in brightness for the 

spectrometer. PeeWee follows the same

FIGURE 3: Design drawing showing the current layout of the confinement building 

and D-wing (on the left). The MACS at NG-0 (kidney-shaped analyzer) and the Double 

Focusing Triple Axis spectrometer at BT-7 to MACS’ right can be seen in the center of the 

figure. To the right of BT-7 is the residual stress facility at BT-8, and beyond that (circular 

gray object) is BT-9, to which MACS will be moved.

FIGURE 4: Design drawing showing the planned layout of the confinement 

building and D-wing post-outage in early 2012 with the new guides installed. 

MACS (analyzer not shown) is in place at BT-9.
54Expansion Initiative

design philosophy applied to the existing cold 

source and utilizes a thermosiphon as the

simplest means to supply liquid hydrogen to 

the source. The new source operates with half 

a liter of liquid hydrogen, as compared to five

liters in the existing cold source, and so the 

additional heat load is readily handled by the 

current refrigerator unit. 

Source facility developments 

Reactor operations and engineering personnel 

will take the opportunity of the outage 

period to schedule a number of projects 

serving to enhance reactor reliability. As part 

of the Initiative, the reactor control room is 

the subject of a program to replace obsolete 

components and a new liner for the fuel 

storage pool is to be fitted. Funding through

the American Recovery and Reinvestment 

Act (ARRA) will improve further source 

operations through replacement of the thermal 

shield system. The thermal shield reduces 

radiation heating in the reactor pressure vessel 

and biological shield by means of water flow

through a series of pipes and ring headers 

located between the vessel and biological 

shield and its replacement is the third and 

final major evolution of work undertaken in

the confinement building during the outage

period.

Post-outage period

Reactor operations are scheduled 

to re-start early in 2012 at which 

time the Facility instrumentation 

will be configured as shown in

Fig. 6. During the first half of 2012,

the remaining sections of the new 

supermirror guides will be installed 

into the new guide hall addition. 

New experimental capabilities 

will be achieved at the end of the 

expansion project in late 2012 (Fig. 

7), after which time the NCNR will 

continue its program of instrument 

development, based around the new 

guide infrastructure.

FIGURE 5: Design drawing showing the location of major components of the BT-9 cold 

source. The H2 condenser is seen above the beam port; warm H2 gas lines run through 

a support structure for MACS to a ballast tank seen on the left. The in-pile assembly is 

shown inset.

FIGURE 6: Expected facility configuration post outage, early 2012.

FIGURE 7: Expected Facility configuration at the end of the Expansion 

Initiative, late 2012.
NCNR 2010 Accomplishments and Opportunities 55

Facility Development

Running in parallel with Expansion Initiative activities 

(ref. to pages containing the Expansion article) and 

construction of new instruments, is a continuous process 

of development and evolution of existing instrumentation, 

software, and sample environment equipment. 

Instrument Development

The past year saw the Multi-Axis Crystal Spectrometer 

(MACS) enter the Facility’s user program and staff have 

engaged in a number of activities designed to both 

enhance the performance and improve the reliability of 

this newly commissioned spectrometer. Installation of a 

new substrate for the air pad floor has reaped benefits of

improved reproducibility and faster repositioning of the 

analyzer. Outfitting the twenty double-crystal analyzers

with new drive trains and absolute multi-turn encoders has 

also resulted in increased precision of movement. And a 

new computer controlled pre-sample optics package now 

permits remote adjustment of beam size and attenuation.

First experiments using the TISANE time-resolved small 

angle scattering technique and equipment installed at the 

NG-7 SANS instrument have been performed this year 

(reference to tSANS article). The TISANE project, funded 

through the Center for High Resolution Neutron Scattering 

(CHRNS), permits dynamic studies of phenomena 

occurring on time scales of 50 μs to 150 μs by time-resolved 

stroboscopic SANS. In-house designed and built dedicated 

timing electronics and histogramming software have been 

used to initiate this program and comparisons of this 

system with the Wiedemann implementation (phase locked

loop synchronized function generators) demonstrate the

performance to be indistinguishable whilst offering a faster 

experiment setup is faster that it is less sensitive to drifts in 

chopper frequency. 

A program to develop and commission new detector 

systems has been established to address the needs of the 

new instrument in the Expansion Initiative. The design 

of the Very Small Angle Neutron Scattering (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. 

A contract for the full complement of the latter has been 

awarded to GE Reuter Stokes, who will manufacture 

8 panels of tube detectors based on a variant of the SNS 

EQ-SANS 8-pack design and electronics conforming to the

SNS data acquisition standard. Testing and commissioning 

of the first of these panels is underway.

Motivated in equal parts by the 3He shortage and spatial 

constraints, a detector system based on scintillator 

technologies is in design for the CANDoR white-beam 

reflectometer. A sliver of 6LiF/ZnS(Ag) impregnated

plastic will produce visible light when struck by neutrons. 

This light is then conducted via wavelength-shifting 

fibers to silicon photomultiplier devices (SiPMs), rather

than conventional photomultiplier tubes. The SiPMs are 

compact, rugged, and inexpensive and have the useful 

characteristic that charge produced by a captured photon 

mimics the charge produced in neutron capture events in 

gas-filled detectors. Detectors so constructed can be very

thin (≈ 1mm), permitting many more channels of crystalanalyzed neutron detection than a similar arrangement

using conventional gas-filled pencil detectors. A prototype

detector has been constructed and preliminary results are 

promising. 

Instrument Control, Data Acquisition, and Software 

Development

The Instrument Control Environment (ICE) software 

system is now fully deployed on the SANS instruments 

in addition to the BT-7 and MACS spectrometers. 

Python scripting capability has now been introduced 

to increase the flexibility of ICE and enable scientists to

FIGURE 1: Prototype scintillator detector showing arrays of 

wavelength-shifting fibers set at various separations for test 

purposes. 
56Facility Development

customize the code particularly in cases of novel

and developmental instrument setup and control 

scenarios. A code freeze will be implemented prior

to the upcoming major facility outage to permit 

refactoring of ICE in preparation for its roll out on 

new instruments within the expansion initiative, and, 

ultimately, to new classes of instruments.

The NCNR raw data archive system has been 

revamped and expanded to include all instruments 

in the scattering suite. In addition to a highly 

available file server, the system has a searchable

metadata catalogue which matches the raw data to 

the experiment responsible for its production. To 

promote better access of facility users to raw data, 

the archived data are mirrored to an externally facing 

web server (http://www.ncnr.nist.gov/ncnrdata). 

Users wishing to keep their experiment data private 

for the 18 month fair use period may opt out of the 

mirror process.

The user experience at the NCNR has also been 

improved by provision of a web application 

displaying live updates of the data being measured 

on each instrument. New data points are displayed 

automatically along with an estimate of completion 

time of the scan, based on the progress of each 

measurement, so that users can check remotely when 

their runs will be complete. The concept of live data 

on the web has also been extended to a prototype 

reduction suite for our triple axis spectrometers 

(TAS). This later project formed the core of a summer 

research project at NCNR for undergraduate and 

high school students. The reduction pipeline can 

include previous measurements such as background 

estimation scans so that the user can easily verify 

that the measurement is capturing the effects they 

expect. This project demonstrates the feasibility of 

creating rich web applications for data reduction, and 

other triple axis tools include an online UB matrix 

calculator and a resolution calculator.

Data Analysis Software Development

The Data Analysis and Visualization Environment

(DAVE) project provides software solutions for a 

range of inelastic neutron scattering instruments at 

the NCNR and other facilities. It is widely used by 

scientists, particularly non-experts, to reduce, view 

and interpret their data. DAVE has been available 

for close to a decade and is now in its second major 

developmental phase that is based on the IDL iTool 

paradigm. This has resulted in improvements in 

many aspects of the application suite, especially with 

regards to usability and visualization functionality.

Many new capabilities were added during the 

past year. The most notable is data reduction and 

visualization support for MACS. Multiple datasets from

MACS can now be read, corrected and readily viewed 

along constant planes in momentum and energy space as 

shown in the Figure below. Another new function included 

is the partial analysis of multiple triple-axis spectrometer 

datasets to identify and extract crystallographic reflections

for subsequent use in other analysis programs such as 

FullProf. The FANS data reduction module has been 

overhauled using iTools hence incorporating benefits

of the framework such as session management, better 

visualization, undo/redo functionality, indexed online

help and much more. This will now serve as a prototypical 

iTool-based data reduction module in DAVE.

Full support and minor changes to existing functionality 

consume a good fraction of development time, typically in 

response to user feedback. Data reduction modules have 

evolved in tracking instrument upgrades and modifications

and data analysis modules have been updated to include 

many new modeling functions. Work on Mslice focused

on optimizing the algorithm used in manipulating multidimensional data and generating slices along a particular 

plane. The time taken to load and calculate projections of 

the data has been dramatically reduced, by up to a factor of 

x50, which is a significant and important gain particular for

modern instrumentation capable of producing large data 

sets of the order of tens of gigabytes.

FIGURE 2: DAVE visualization of dispersion curves and continuum 

measured from an iron-based multiferroic compound on MACS.

Finally, IDL 8.0 was released recently with many language 

enhancements and upgrades to the iTool framework which 

will be of immediate benefit for DAVE. The intention

is to release DAVE using IDL 8.0 in the near future and 

following an appropriate evaluation process.

The development of reflectometry analysis tools –

REFLPAK - has continued over the past year with the 

emphasis on making techniques such as simultaneous 

fitting and direct inversion accessible to more users.

New constrained optimizers are much more robust,

allowing users to find better fits with to the model with

less interaction with the program and new Markov chain 

Monte Carlo (MCMC) code incorporates a Bayesian 

approach to uncertainty analysis, allowing instrumental 
NCNR 2010 Accomplishments and Opportunities 57

effects to be properly reflected in the uncertainty of the

fitted model. The resulting joint parameter probability

function makes plain any hidden correlations in the 

model parameters. Also under development is general 

off-specular reflectometry modeling software to analyze

data from MAGIk, the dedicated off-specular reflectometer

instrument to be built as part of the Expansion Initiative, 

as well as the Liquids and Magnetic reflectometers at the

SNS. As a first step, modeling of a substrate modified

Born approximation including refraction effects has been 

implemented, and this will be extended to a more complete 

distorted wave Born approximation. This software can 

take advantage of modern graphics processors for fast 

calculation of arbitrary structures.

Sample Environment

NCNR personnel support a diverse range of sample 

environment equipment required for user research 

program. During the past year a number of new pieces of 

equipment have been acquired to support, in particular, 

the operational capacity and reliability of low-temperature 

operations. A non-magnetic dilution refrigerator provides 

sample temperatures down to 30 mK and is suitable for 

use on a number of instruments including DCS, Spin Echo, 

MACS, and all the triple-axis spectrometers. This new 

low-temperature capability complements the 11.5 Tesla 

superconducting magnet/dilution refrigerator, which 

was returned to service this year following repairs and 

refurbishment. Two new bottom-loading 4 K closed-cycle 

refrigerators (CCRs) were also added to the equipment 

roster. These new CCRs are fully compatible with existing 

tailsets and specialty vacuum cans, yet offer more sample 

space and a lower background signature. The NCNR 

received a new 10 Tesla cryogen-free magnet this year. 

Coupled with a cryogen-free 1.5 K insert that is currently 

on order, and optionally the non-magnetic dilution 

refrigerator received this year, this complete system will 

afford the researcher up to 10 Tesla and temperatures 

from 30 mK to 700 K in a completely “dry” system. NISTdeveloped safety venting mechanisms are currently being 

implemented across the top-loading CCRs and ILL orange 

cryostats to prevent the potentially explosive buildup of 

pressure possible below an ice blockage in the sample well. 

A new SANS rheometer affords a much-needed upgrade to 

this popular choice, including new sample thickness and 

sample geometry options. The USANS instrument now 

has a new, dedicated refrigerated/heating circulator that 

operates from -40  ̊C to 200  ̊C and works in conjunction

with a new multiple-position sample changer. 

User demand for 3He neutron spin filters (NSFs) continues

to grow at a rapid rate. The NCNR’s program to provide 

and develop NSFs is run in collaboration with the Physics 

Laboratory at NIST, and in the past year has serviced 30 

user experiments totaling over 100 days of beam time. 

Polarized beam experiments are routinely carried out on

the thermal neutron triple-axis spectrometer BT-7, smallangle neutron scattering instruments, and reflectometers,

along with preliminary commissioning experiments on 

MACS. 

The user program is underpinned by a strong technical 

development program. Polarization of the NSFs is achieved

by SEOP (spin-exchange optical pumping) and following 

a doubling of the laser power and modifications to the

spectral narrowing scheme for each system the 3He gas 

can now be polarized some 50 % faster. This improves

significantly the time-averaged polarized neutronic

performance of the cells and is particularly important for 

polarized beam experiments where the signal is low

There is a continued drive to develop user-friendly 

hardware and software to control 3He NSFs that are readily 

incorporated into the instrument software. Programs to 

predict and monitor the polarized neutronic performance

and flip the 3He polarization during the user’s experiment

on each instrument have now been implemented. This 

represents the first steps toward full automation of flipping

3He polarization, thus neutron polarization flipping,

controlled by the instrument computer. 

The performance of the filters continues to improve

with notable advances in hardware for each instrument 

class. On BT-7, the relaxation time of the polarizer has

been improved by an order of magnitude following 

the development of a new double-layer mu-metal endcompensated ‘magic box’ capable of providing a magnetic 

field of 3.9 mT - more than 3 times higher than the regular

box. The high-field box makes the 3He polarization

decay less sensitive to the external stray field around

the instrument and thus operation of polarized beam

experiments much more reliable. 

Development activity for SANS experiments has focused 

on a low-field magnetostatic cavity. In this case the

aim once more is to provide a homogeneous field for

maintaining the 3He polarization, and one appropriate to

cover the entire Q range of the instruments. This device

has been tested offline and on NG-3 where it extends the

Q range for loss-free neutron spins by at least a factor

of two. The device will be ready for user experiments 

following implementation of the NMR based method for 

3He flipping. Envisaged is the integration of an in-situ

spin-exchange optical pumping scheme into this device, 

improving further the polarized neutronic performance.

Finally, cells for reflectometry measurements now operate

reliably with an initial flipping ratio of 50 % to 70 % and

3He polarization relaxation of about 300 h. Therefore the

time-averaged polarized neutronic performance over a two

day period is comparable to that predicted for in-situ SEOP 

operation.
58Serving

Serving the Science and Technology Community

The 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:

•	 Andrew Allen (NIST Ceramics Division)

•	 Jeffrey Allen (Michigan Technological University)

•	 Collin Broholm (Johns Hopkins University)

•	 Leslie Butler (Louisiana State University)

•	 Kalina Hristova (Johns Hopkins University)

•	 Ramanan Krishnamoorti (University of Houston)

•	 Valery Kiryukhin (Rutgers University)

•	 Raul Lobo (University of Delaware)

•	 Lee Magid (University of Tennessee, Knoxville)

•	 Janna Maranas (The Pennsylvania State University)

•	 Alan Nakatani (Rohm and Haas Company)

•	 Stephan Rosenkranz (Argonne National Laboratory)

•	 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 at the NCNR

The NCNR continued its strong record of serving the U.S. 

research community this year. Over the 2010 fiscal year, 2290

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.) Research participants 

represented 223 external institutions, including 146 U.S. 

universities, 32 national laboratories, and 45 U.S. industries. The 

NCNR is a national facility, with participants from 42 states, DC, 

and Puerto Rico. 

FIGURE 1: Research participants at the NCNR 1986-2010 

2010 NCNR Proposal Program

Two calls in the past year resulted in the submission of 745 

proposals, a record number, of which 392 were approved and 

received beam time. The oversubscription, i.e., the ratio of 

days requested on all proposals to the days available, was 2.5 
NCNR 2010 Accomplishments and Opportunities 59

on the average, but as high as 6 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 eight years. The following table shows the data for several 

instrument classes.

Instrument class Proposals Days requested Days allocated

SANS and USANS 255 947 406

Reflectometers 108 767 364

Spectrometers 334 2327 805

Diffraction 20 99 47

Imaging 28 134 61

Total 745 4269 1683

User Group Holds Third Election

The NCNR Users Group (NUG) provides an independent forum 

for all facility users to raise issues to NCNR management, 

working through its executive officers to carry out this function. 

In December 2009, the NUG conducted its third online election 

of officers, a process scheduled every other year The newly

elected NUG Executive Committee members are Despina Louca 

(University of Virginia), Dale Schaefer (University of Cincinnati), 

John Katsaras (Oak Ridge National Laboratory), and Erik Watkins

(University of California, Davis). Three members remain in 

office for two more years. They are Mark Dadmun (University of

Tennessee, chair), Michel Kenzelmann (Paul Scherrer Institute,

Switzerland), and Lynn Walker (Carnegie-Mellon University). In

late 2010, the NUG will conduct a comprehensive survey of user 

satisfaction and concerns, addressing areas such as support from 

NCNR staff, proposal review, sample environments, instrument 

hardware and software, data analysis, and user laboratories.

Panel of Assessment

The major organizational components of NIST are evaluated

periodically 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 reported on the NIST 

Center of Neutron Research in January 2009. Their findings are

summarized in a document that may be viewed online at http://

www.nap.edu/openbook.php?record_id=12765&page=R1.

The panel members included Tonya Kuhl of the University of 

California, Davis (chair), Frank Bates, University of Minnesota, C. 

W. (Paul) Chu, University of Houston, Donald Engelmann, Yale

University, Christopher Gould, North Carolina State University, 

Alexander Grosberg, New York University, Russell Hemley, 

Carnegie Institution of Washington, Herbert Mook, Oak Ridge

National Laboratory, Sunil Sinha, University of California, San 

Diego, and Barbara Wyslouzil, the Ohio State University.

The Center for High Resolution Neutron 

Scattering (CHRNS)

The 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 spectrometers and diffractometers at the NCNR, enabling 

users from around the nation and the world to observe dynamical 

phenomena involving energies from ≈ 30 neV to ≈ 100 meV, and

to obtain structural information on length scales from 1 nm 

to ≈ 10 μm. A more detailed account of CHRNS activities may be

found on pp 60-62 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 

research at the NG-7 30 m SANS instrument. The consortium uses 

65 % of the beam time on this instrument, with the remaining 

35 % allocated to the general scientific community through

the NCNR’s proposal system. Consortium members conduct 

independent research programs primarily in the area of largescale structure in soft matter. For example, ExxonMobil has used 

this instrument to deepen their understanding of the underlying 

nature of ExxonMobil’s products and processes, especially in the 

fields of polymers, complex fluids, and petroleum mixtures.

NIST / General Motors – Neutron Imaging

An ongoing partnership and collaboration between General 

Motors and NIST has resulted in an exciting use of neutron 

imaging 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. With a newly developed 10 μm

spatial resolution detector, studies of the transport phenomena 

from the anode to the cathode in fuel cells and batteries have 

been conducted. 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.

Interagency Collaborations

The Smithsonian Institution’s Nuclear Laboratory for 

Archeological Research is part of the Anthropology Department at 

the National Museum of Natural History. It has had a productive 

32 year partnership with the NCNR, during which time it has 

chemically analyzed over 41 000 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. Ongoing work includes studies of cryogenic 

homogenization of foods, preparation of an in-house swordfish

reference material, improved detection capabilities for toxic 

and nutritional elements in foods, and rapid screening of food 

products for dangerous levels of cadmium, lead, and mercury in 

beverages and residual bromine in baked goods. Recent studies 

include the investigation of possible procedural losses from foods 

of several elements, including mercury, bromine, and selenium. 
60CHRNS

The Center for High Resolution Neutron Scattering 

(CHRNS)

The Center for High Resolution Neutron Scattering (CHRNS) is a national user facility that is jointly 

funded by the National Science Foundation through 

its Division of Materials Research (grant numbers 

DMR-0454672 and 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

CHRNS supports operation of the 30-meter Small 

Angle Neutron Scattering (SANS) instrument, the 

Ultra-Small Angle Neutron Scattering (USANS) 

instrument, the Spin-Polarized Inelastic Neutron

Scattering (SPINS) spectrometer, the Multi-Angle Crystal 

Spectrometer (MACS), the Disk Chopper Spectrometer 

(DCS), the High Flux Backscattering Spectrometer (HFBS), 

and the Neutron Spin-Echo (NSE) spectrometer. 

The small angle scattering instruments supported by 

CHRNS provide structural information over length scales 

from ≈ 1 nm to ≈ 10 μm. The spectrometers collectively

yield dynamical information over time scales from ≈

3X10-14 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 26), 227 of the 

391 proposals received were for the six CHRNS-operated 

instruments. There were also 14 proposals for MACS. Of 

the 227 proposals, 122 received awarded beam time (as well 

as 7 for MACS). Of the 1262 days requested, the Beam Time 

Allocation Committee approved 537. 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. 65) over the current one-year period are based on 

FIGURE 1: NCNR 2010 Summer School participants
NCNR 2010 Accomplishments and Opportunities 61

research performed using these instruments. In 2009 more 

than 25 Ph.D. theses were completed using results from 

CHRNS-sponsored instruments.

Scientific Support Services

An important ingredient of the CHRNS operation is its 

support of staff whose responsibility is to provide services 

that are essential to the success of neutron scattering 

investigations. One such service is the provision and 

operation of an expanding range of sample environment 

equipment. The sample environment team often takes 

on projects to expand the range of existing equipment, 

enhance its safety, improve its reliability, and even develop 

entirely new capabilities. For example, a new ten Tesla 

magnet and a new dilution refrigerator were added to our 

suite of equipment.

Other services include the maintenance of several wellequipped user laboratories, and the development, 

documentation and maintenance 

of data reduction, visualization,

and analysis software through the 

DAVE project; DAVE is a suite of 

programs that enables users to 

rapidly reduce, examine and display 

their experimental data. It may be 

downloaded free of charge from the 

website http://www.ncnr.nist.gov/

dave/, either as a binary executable 

with an embedded runtime license 

or as the complete source code. 

A major addition to DAVE over the 

past year has been data reduction 

and visualization support for the

new Multi-Axis Crystal Spectrometer 

(MACS). This provides users with a 

useful and easy way of decomposing 

the large and intricate data generated 

by the instrument.

Education and Outreach

One of the missions of the CHRNS 

program is to contribute to the 

development of human resources 

through education and outreach, 

thereby fostering future generations 

of scientists and neutron scatterers.

This was the 16th annual CHRNS sponsored neutron 

scattering summer school. The 2010 school, devoted to 

small angle neutron scattering and neutron reflectometry,

attracted 90 applicants for the 36 available places. The 

CHRNS summer schools are very effective in educating 

potential new users of neutron scattering as more than 70 % 

of the participants return to the NCNR for their own 

research. Course materials have been placed on the Web at

http://www.ncnr.nist.gov/programs/CHRNS/outreach_

ssmaterials.html.

We also offered a series of tutorial demonstrations based on

the experiments and lectures presented at the 2009 Summer 

School on Neutron Spectroscopy. Ten participants, from 

US universities and from six NIST divisions other than the 

NCNR, attended the tutorials. Tutorial course materials

may be found on the Web, at http://www.ncnr.nist.gov/

programs/CHRNS/outreach_tutorialmaterials.html. 

FIGURE 2: The 2010 SURF students, NCNR advisors, and other staff

FIGURE 3: Middle school science teachers and NCNR/CHRNS staff
62CHRNS

CHRNS once again participated in NIST’s Summer 

Undergraduate Research Fellowship (SURF) 

program, hosting seven undergraduate students 

who worked with staff members studying topics 

such as frustrated magnetism, magnetic recording 

materials, superconductors, and data analysis 

software development. The students enthusiastically 

agreed that their summer research experiences were 

productive and worthwhile, and their advisors 

benefited from their efforts, expanding their

understanding of the scientific process.

This year the NCNR participated in 

the new NIST Summer High School 

Internship Program, known as the 

SHIP. Four students from Montgomery 

County Schools participated in the 

program. Alex Yee and Ophir Lifshitz,

advised by William Ratcliff worked

on a project called WRED: Data

fitting and calculation in a web-based

environment. Pavan Bhargava and 

his advisor Joseph Dura worked on 

the production of novel Nafion thin

films for the development of lipid

bilayers. Jonathan Shear, with advisor 

Efrain Rodriguez, worked on Neutron 

Studies of Magnetism and the Crystal 

Structure of Chromium Tellurides and 

their Potential for Magnetic Refrigeration. 

This was the fourth year that 

NIST organized a “Summer

Institute” for middle school 

science teachers. This year we had 

twenty-one teachers from three 

Maryland counties, and from the 

state of Florida. They toured the 

NCNR and attended lectures and 

demonstrations that described 

how neutrons are used to probe 

matter. They were also provided 

the opportunity to interact with 

facility users, SURF students and 

the scientific staff. The neutron

scattering component of the 

Summer Institute gave teachers a 

greater appreciation of what can 

be accomplished using neutron 

scattering. 

Other education and outreach activities included “Bring 

your Kids to Work Day”, and tours for middle school

and high school students. During the “Bring your Kids to 

Work Day”, held every year in the month of April, NIST

opens its doors to more than 250 students ranging from 6th 

through 12th grades. Within this site-wide yearly program,

the NCNR prepares tours of the facility, lectures and 

demonstrations specially designed for middle school age 

children on how neutrons are used to probe matter.

FIGURE 4: Participants and NCNR/CHRNS staff at the HFBS/DCS tutorial

FIGURE 5: left to right: Vikas Bhatia (SURF) and Jonathan Schear (SHIP)
NCNR 2010 Accomplishments and Opportunities 63

Awards 2010

Turkish president Abdullah 

Gül awards Taner Yildirim 

(right) of the NCNR the Special 

Award for 2009 from Tubitak, 

the Scientific and Technological

Research Council of Turkey. The 

award is reserved for Turkish 

scientists working abroad, and is 

among Turkey’s highest awards for scientific achievement. 

Collin Broholm of Johns Hopkins 

University and the NCNR has been 

awarded the NSSA Sustained Research 

Prize by the Neutron Scattering Society 

of America (NSSA) for “outstanding 

neutron scattering studies of correlated 

electron physics in magnets, metals and 

superconductors, and for science-driven 

development ofneutron scattering techniques”. Broholm was also 

selected as a Fellow by the NSSA for “outstanding neutron 

scattering studies of correlated electron physics in magnets, metals 

and superconductors, and for science-driven development of neutron 

scattering techniques.”

Craig Brown of the NCNR has been 

awarded the 2010 Science Prize by the 

Neutron Scattering Society of America for 

“For outstanding neutron scattering studies 

of hydrogen-framework interactions in metalorganic frameworks.”

Jeff Lynn of the NCNR has been selected 

as a Fellow by the Neutron Scattering 

Society of America for “seminal studies of 

the colossal magneto- resistance effect and his 

many contributions to our understanding of the 

interplay of magnetism and superconductivity.”

Chuck Majkrzak of the NCNR has been 

selected as a Fellow by the Neutron 

Scattering Society of America for 

“fundamental contributions to the development 

of neutron reflectivity.”

Dan Neumann of the NCNR has been 

selected as a Fellow by the Neutron 

Scattering Society of America for 

“outstanding research using inelastic and 

quasielastic neutron scattering on carbon 

containing and other diverse materials and 

exceptional leadership in serving and expanding 

the American neutron community.”

Wen-Li Wu of the NIST Polymers Division 

has been selected as a Fellow by the 

Neutron Scattering Society of America for 

“important contributions to a broad range of 

problems in polymer science and in its industrial 

application using neutron scattering.

Tom Gentile of the Ionizing Radiation

Division at the NCNR has been appointed 

Fellow of the American Physical Society “For 

his extensive contributions to diverse precision 

measurements, particularly in the development 

of neutron spin filters using polarized 3He and 

in the application of polarized 3He to precision 

measurements in neutron science.“

NCNR’s William Ratcliff was named a 

Minority Research Trailblazer for his work 

on frustrated magnetic systems and was 

recognized at the 24th annual BEYA Science, 

Technology, Engineering, and Math Global 

Competitiveness Conference.

William Kamitakahara of the NCNR was 

given the NIST 

Colleague’s Choice Award for “creating and 

designing the NCNR proposal system, which 

is the backbone of the scientific operations of 

the NCNR and is broadly hailed by the user 

community as among the best...in the world.”

Muhammad Arif and

David Jacobson the Ionizing

Radiation Division at the 

NCNR were awarded the 

DOC Gold Medal for 

scientific/engineering

achievement in “developing 

the world’s most advanced 

neutron imaging station and for applying cutting-edge neutron 

tomography techniques to study water transport in hydrogen fuel 

cells.”

Qingzhen Huang of the NCNR was 

awarded the DOC Silver Medal for 

scientific/engineering achievement. He is

recognized for “his pioneering use of neutron 

diffraction to reveal key relationships between 

the bulk magnetic and structural properties that 

led directly to the development of an entirely 

new class of magnetocaloric materials which 

exhibit superior performance.”
64Awards

Yiming Qiu of the NCNR is 

the recipient of the 2010 Award 

for Scientific Support by the 

NIST chapter of Sigma Xi. As an 

instrument scientist for the Disk 

Chopper Spectrometer, Dr. Qiu

assists visiting scientists in all aspects 

of their experiments, from proposal 

writing through planning, execution, and interpretation, 

to write-up for publication. Yiming is an internationally 

recognized expert in the application of neutron

scattering techniques to condensed matter physics.

Juscelino Leão of the NCNR was 

awarded the DOC Bronze Medal for

“his development of new pressure cells 

which enable NCNR facility users to 

study samples under hydrostatic pressures 

as high as 1 GPa and at temperatures 

between 1.1 K and 400 K.”

Muhammad Arif, Patrick Hughes, Alan K. Thompson 

of the Ionizing Radiation Division at the NCNR along

with Charles W. Clark and Robert E. Vest of the Physics

Division were awarded the DOC Bronze Medal for 

developing a novel approach for “detecting neutrons 

using Lyman alpha light produced by the hydrogen atoms 

generated in the absorption of neutrons by helium-3.”

Andrew Allen of the MSEL was 

awarded the DOC Bronze Medal for 

his “exceptional leadership in the design, 

assembly, testing, and commissioning 

of a best-in-the-world ultra-small-angle 

x-ray scattering instrument”. Allen has 

also often used small angle neutron 

scattering facilities at the NCNR.

Kathryn Krycka of the NCNR was 

selected by the NIST chapter of 

Sigma Xi for a 2010 outstanding 

poster award for her presentation:

“Core-Shell Magnetic Morphology 

within Fe3O4 Nanoparticles.”

Chris Metting of the University of 

Md and the NCNR took 2nd place in 

the ACNS Poster Competition for 

his poster entitled “Characterization 

and modeling of off-specular neutron 

scattering for analysis of two dimensional 

ordered structures” at the 2010 American 

Conference on Neutron Scattering.

Ping-Yen Hsieh of the University of Md 

and the NCNR took 3rd place in the ACNS 

Poster Competition for his poster entitled 

“The gas adsorption behaviors in chiral holmium 

metal-organic framework materials” at the 

2010 American Conference on Neutron 

Scattering.

Wendy Queen of the NCNR was selected 

for an Outstanding Graduate Researcher 

Award by the Dept. of Chemistry at

Clemson University upon receiving 

her Ph.D.

Herb Mook of Oak Ridge National Laboratory 

and a user at the NCNR has been awarded 

the Clifford G. Shull Prize by the Neutron 

Scattering Society of America for “outstanding 

contributions to the study of magnetism, 

superconductivity, and quantum phenomena in 

matter with neutrons.”

Professor Sang Wook Cheong of 

Rutgers University was awarded the 

American Physical Society’s James C. 

McGroddy Prize for New Materials 

by “For groundbreaking contributions in 

theory and experiment that have advanced 

the understanding and utility of multiferroic 

oxides.” Cheong’s group has collaborated 

with NCNR workers on measurements of BiFeO3 at the BT-9 

and BT-7 spectrometers.

Caltech Professor Brent Fultz was given 

the Minerals, Metals and Materials Society’s 

Electronic, Magnetic & Photonic Materials 

Division Distinguished Scientist/Engineer 

award “For his outstanding contribution to 

fundamental understanding of thermodynamics 

in materials using inelastic neutron scattering.” 

Fultz’ group has conducted work at

the NCNR.

David J. Lohse of ExxonMobil along with 

Nikos Hadjichristidis of the University 

of Athens, Greece, were selected by the 

Division of Polymer Materials of the 

American Chemical Society for the 2010 

Cooperative Research Award in Polymer 

Science and Engineering sponsored by the 

Eastman Kodak Company. Dr. Lohse’s work 

has included use of the NG-7 SANS instrument at the NCNR.

Stony Brook University graduate student 

Jinsheng Wen has been named a winner of 

the 2009 Chinese Government Award for 

Outstanding Self-Financed Students Studying 

Abroad. Wen has conducted many of his

neutron measurements on superconductors at 

the NCNR.
NCNR 2010 Accomplishments and Opportunities 65

Publications: August 1, 2009 to July 31, 2010

Abdurashitov, J.N., Gavrin, V.N., Gorbachev, V.V., Gurkina, P.P., 

Ibragimova, T.V., Kalikhov, A.V., Khairnasov, N.G., Knodel, 

T.V., Mirmov, I.N., Shikhin, A.A., Veretenkin, E.P., Yants, V.E., 

Zatsepin, G.T., Bowles, T.J., Elliott, S.R., Teasdale, W.A., Nico,

J.S., Cleveland, B.T., Wilkerson, J.F., “Measurement of the

Solar Neutrino Capture Rate with Gallium Metal. III. Results 

for the 2002-2007 Data-taking Period,” Phys. Rev. C 80(1), 

015807-1 (2009).

Adriano, C., Giles, C., Bittar, E.M., Coelho, L.N., de Bergevin, F., 

Mazzoli, C., Paolasini, L., Ratcliff, W., Bindel, R., Lynn, J.W.,

Fisk, Z., Pagliuso, P.G., “Cd Doping Effects in the HeavyFermion Compounds Ce2MIn8 (M=Rh and Ir),” Phys. Rev. B

81(24), 245115-1 (2010).

Ainalem, M.-L., Kristen, N., Edler, K.J., Höök, F., Sparr, E., 

Nylander, T., “DNA Binding to Zwitterionic Model

Membranes,” Langmuir 26(7), 4965 (2010).

Ainalem, M.-L, Campbell, R.A., Nylander, T., “Interactions 

between DNA and Poly(amido amine) Dendrimers on Silica 

Surfaces,” Langmuir 26(11), 8625 (2010).

Akgun, B., Uğur, G., Brittain, W.J., Majkrzak, C.F., Li, X., Wang, J.,

Li, H., Wu, D.T., Wang, Q., Foster, M.D., “Internal Structure

of Ultrathin Diblock Copolymer Brushes,” Macromol. 42, 

8411 (2009).

Alsmadi, A.M., Alyones, S., Mielke, C.H., McDonald, R.D., Zapf,

V., Altarawneh, M.M., Lacerda, A., Chang, S., Adak, S., 

Kothapalli, K., Nakotte, H., “Complex Conductivity of UTX

Compounds in High Magnetic Fields,” J. Appl. Phys. 105(7), 

07E108-1 (2009).

Alsmadi, A.M., Alyones, S., Mielke, C.H., McDonald, R.D., 

Zapf, V., Altarawneh, M.M., Lacerda, A., Chang, S., Adak, S.,

Kothapalli, K., Nakotte, H., “Radio-Frequency Measurements 

of UNiX Compounds (X = Al, Ga, Ge) in High Magnetic

Fields,” J. Magn. Magn. Mater. 321(22), 3712 (2009).

Altunbas, A., Sharma, N., Lamm, M.S., Yan, C., Nagarkar, 

R.P., Schneider, J.P., Pochan, D.J., “Peptide-Silica Hybrid 

Networks: Biomimetic Control of Network Mechanical 

Behavior,” ACS Nano 4(1), 181 (2010).

Anderson, D.L., “Analysis of Beverages for Hg, As, Pb, and Cd 

with a Field Portable X-Ray Fluorescence Analyzer,”

J. AOAC Int. 93(2), 683 (2010).

Anderson, D.L., “Analytical Capabilities of Anticoincidence INAA 

for Biological Materials,” J. Radioanal. Nucl. Chem. 282, 75 

(2009).

Anderson, D.L., “Screening of Foods and Related Products for 

Toxic Elements with a Portable X-Ray Tube Analyzer,”

J. Radioanal. Nucl. Chem. 282(2), 415 (2009).

Anderson, D.L., “Use of L-Cysteine for Minimization of Inorganic

Hg Loss during Thermal Neutron Irradiation,” J. Radioanal. 

Nucl. Chem. 282(1), 11 (2009).

Anovitz, L.M., Lynn, G.W., Cole, D.R., Rother, G., Allard, L.F.,

Hamilton, W.A., Porcar, L., Kim, M.-H., “A New Approach

to Quantification of Metamorphism using Ultra-Small and

Small Angle Neutron Scattering,” Geochim. Cosmochim. 

Acta. 73, 7303 (2009). [CHRNS]

Argyriou, D.N., Hiess, A., Akbari, A., Eremin, I., Korshunov, 

M.M., Hu, J., Qian, B., Mao, Z., Qiu, Y., Broholm, C., Bao, W.,

“Incommensurate Itinerant Antiferromagnetic Excitations 

and Spin Resonance in the FeTe0.6Se0.4 Superconductor,” 

Phys. Rev. B 81(22), 220503-1 (2010).

Ashkar, R., Stonaha, P., Washington, A.L., Shah, V.R.,

Fitzsimmons, M.R., Maranville, B., Majkrzak, C.F., Lee, W.T.,

Schaich, W.L., Pynn, R., “Dynamical Theory Calculations

of Spin-Echo Resolved Grazing-Incidence Scattering from a

Diffraction Grating,” J. Appl. Crystallogr. 43, 455 (2010).

Azuah, R.T., Kneller, L.R., Qiu, Y., Tregenna-Piggott, P.L.W.,

Brown, C.M., Copley, J.R.D., Dimeo, R.M., “DAVE: 

A Comprehensive Software Suite for the Reduction, 

Visualization, and Analysis of Low Energy Neutron

Spectroscopic Data,” J. Res. Natl. Inst. Stand. Technol. 114(6), 

341 (2009). [CHRNS]

Babcock, E., Boag, S., Becker, M., Chen, W.C., Chupp, T.E., Gentile,

T.R., Jones, G.L., Petukhov, A.K., Soldner, T., Walker, T.G.,

“Effects of High-Flux Neutron Beams on 3He Cells Polarized

in situ with Spin-Exchange Optical Pumping,” Phys. Rev. A 

80(3), 033414-1 (2009).

Babcock, E., Boag, S., Andersen, K.H., Becker, M., Beecham, 

C., Bordenave, F., Chastagnier, J., Chen, W.C., Chung, R.,

Chupp, T.E., Elmore, S., Fouilloux, P., Gentile, T.R., Jullien, 

D., Lelievre-Berna, E., Mouveau, P., Petoukhov, A., Revert, 

M., Soldner, T., “In-Situ SEOP Polarizer and Initial Tests on a

High Flux Neutron Beam,” Physica B 404, 2655 (2009).

Barbour, A.M., Telling, M.T.F., Larese, J.Z., “Investigation of the

Behavior of Ethylene Molecular Films Using High Resolution 

Adsorption Isotherms and Neutron Scattering,” Langmuir 

26(11), 8113 (2010). [CHRNS]

Bass, C.D., Bass, T.D., Heckel, B.R., Huffer, C.R., Luo, D., Markoff, 

D.M., Micherdzinksa, A.M., Snow, W.M., Swanson, H.E.,

Walbridge, S.C., “A Liquid Helium Target System for a

Measurement of Parity Violation in Neutron Spin Rotation,” 

Nucl. Instrum. Meth. A 612, 69 (2009).

Bay, D.C., Budiman, R.A., Nieh, M.-P., Turner, R.J., “Multimeric 

Forms of the Small Multidrug Resistance Protein EmrE in 

Anionic Detergent,” Biochim. Biophys. Acta. 1798, 526 (2010).
66Publications

Beekman, M., Stefanoski, S., Wong-Ng, W., Kaduk, J.A.,

Huang, Q., Reeg, C., Bowers, C.R., Nolas, G.S.,

“Structure and Thermal Conductivity of Na1-xGe3+z,” 

J. Solid State Chem. 183, 1272 (2010).

Ben, T., Ren, H., Ma, S., Cao, D., Lan, J., Jing, X., Wang, W.,

Xu, J., Deng, F., Simmons, J.M., Qiu, S., Zhu, G.,

“Targeted Synthesis of a Porous Aromatic Framework 

with High Stability and Exceptionally High Surface 

Area,” Angew. Chem. Int. Edit. 48, 9457 (2009).

Bhattacharya, S., Dai, Z., Li, J., Baxter, S., Callaway, D.J.E.,

Cowburn, D., Bu, Z., “A Conformational Switch in the

Scaffolding Protein NHERF1 Controls Autoinhibition 

and Complex Formation,” J. Biol. Chem. 285(13), 9981 

(2010).

Boag, S., Babcock, E., Andersen, K.H., Becker, M., 

Charlton, T.R., Chen, W.C., Dalgliesh, R.M.,

Elmore, S.D., Frost, C.D., Gentile, T.R., Lopez Anton,

R., Parnell, S.R., Petoukhov, A.K., Skoda, M.W.A.,

Soldner, T., “In Situ SEOP Polarised 3He Neutron Spin 

Filter for Incident Beam Polarisation and Polarisation 

Analysis on Neutron Scattering Instruments,” Physica 

B 404, 2659 (2009).

Bode, P., Greenberg, R.R., De Nadai F., Elisabete A., 

“Neutron Activation Analysis: A Primary (Ratio) 

Method to Determine Si-Traceable Values of Element 

Content in Complex Samples,” CHIMA 63(10), 678 

(2009).

Boggara, M.B., Krishnamoorti, R., “Small-Angle Neutron 

Scattering Studies of Phospholipid-NSAID Adducts,” 

Langmuir 26(8), 5734 (2010).

Boggara, M.B., Faraone, A., Krishnamoorti, R., “Effect of 

pH and Ibuprofen on Phospholipid Bilayer Bending 

Modulus,” J. Phys. Chem. B 114, 8061 (2010). [CHRNS]

Boland, E.K., Liu, J., Maranas, J.K., “A Molecular Picture 

of Motion in Polyolefins,” J. Chem. Phys. 132(14), 

144901-1 (2010). [CHRNS]

Borgmeyer, B., Wilson, C., Winholtz, R.A., Ma, H.B.,

Jacobson, D., Hussey, D., “Heat Transport Capability 

and Fluid Flow Neutron Radiography of ThreeDimensional Oscillating Heat Pipes,” J. Heat Transfer 

132, 061502-1 (2010).

Bridges, C.A., Krishnamurthy, V.V., Poulton, S., 

Paranthaman, M.P., Sales, B.C., Myers, C., Bobev, S., 

“Magnetic Order in CaMn2Sb2 Studied via Powder 

Neutron Diffraction,” J. Magn. Magn. Mater. 321(22), 

3653 (2009).

Brown, C.M., Sumida, K., Long, J.R., “Understanding 

Physisorbed Hydrogen Systems Using Neutrons,” 

in “ACS Division Proceedings, Division of Fuel 

Chemistry,” edited by unknown, (ACS, Fall National 

Meeting & Exposition 2009 Conf. Proc., August 2009, 

Washington, D.C.) 54(2), (2009).

Caba, B.L., Zhang, Q., Carroll, M.R.J., Woodward, R.C., St. Pierre,

T.G., Gilbert, E.P., Riffle, J.S., Davis, R.M., “Nanostructure

of PEO-polyurethane-PEO Triblock Copolymer Micelles in 

Water,” J. Colloid Interface Sci. 344, 81 (2010).

Cabassi, R., Bolzoni, F., Gilioli, E., Bissoli, F., Prodi, A., Gauzzi, A.,

“Jahn-Teller-Induced Crossover of the Paramagnetic 

Response in the Singly Valent eg System LaMn7O12,” 

Phys. Rev. B 81(21), 214412-1 (2010).

Cabrera, I., Kenzelmann, M., Lawes, G., Chen, Y., Chen, W.C.,

Erwin, R., Gentile, T.R., Leao, J.B., Lynn, J.W., Rogado, N.,

Cava, R.J., Broholm, C., “Coupled Magnetic and Ferroelectric 

Domains in Multiferroic Ni3V2O8,” Phys. Rev. Lett. 103(8), 

087201-1 (2009).

Cao, L.R., Hattrick-Simpers, J.R., Bindel, R., Tomlin, B.E., Zeisler,

R., Paul, R., Bendersky, L.A., Downing, R.G., “Combinatorial 

Study of Thin Film Metal Hydride by Prompt Gamma 

Activation Analysis,” J. Radioanal. Nucl. Chem. 283, 63 

(2010).

Cappelletti, R.L., editor, “2009 NIST Center for Neutron Research 

Accomplishments and Opportunities,” NIST SP 1105 (2009).

Chambrier, M.-H., Ibberson, R.M., Goutenoire, F., “Structure 

Determination of α-La6W2O15,” J. Solid State Chem. 183, 1297 

(2010).

Chang, L.J., Huang, D.J., Li, W.-H., Cheong, S.-W., Ratcliff, W.,

Lynn, J.W., “Crossover from Incommensurate to

Commensurate Magnetic orderings in CoCr2O4,” J. Phys.: 

Condens. Matter 21, 456008 (2009).

Chang, L.J., Prager, M., PerBon, J., Walter, J., Jansen, E., Chen, Y.Y.,

Gardner, J.S., “Magnetic Order in the Double Pyrochlore 

Tb2Ru2O7,” J. Phys: Condens. Matter 22, 076003 (2010).

Chatjaroenporn, K., Baker, R.W., Fitzgerald, P.A., Warr, G.G.,

“Polymerizable Cationic Micelles Form Cylinders at

Intermediate Conversions,” Langmuir 26(14), 11715 (2010).

Chen, S.H., Mallamace, F., Chu, X.Q., Kim, C., Lagi, M., Faraone,

A., Fratini, E., Baglioni, P., “Neutron Scattering Studies of 

Dynamic Crossover Phenomena in a Coupled System of 

Biopolymer and its Hydration Water,” J. Phys.: Conf. Ser.

177(1), 021006 (2009). [CHRNS]

Chen, S.-H., Lagi, M., Chu, X.-Q., Zhang, Y., Kim, C., Faraone, A.,

Fratini, E., Baglioni, P., “Dynamics of a Globular Protein and 

its Hydration Water Studied by Neutron Scattering and MD

Simulations,” Spectroscopy 24(1-2), 1 (2010). [CHRNS]

Chen, S.H., Zhang, Y., Lagi, M., Chong, S.H., Baglioni, P.,

Mallamace, F., “Evidence of Dynamic Crossover Phenomena 

in Water and Other Glass-Forming Liquids: Experiments,

MD Simulations and Theory,” 

J. Phys.: Condens. Matter 21, 504102 (2009). [CHRNS]

Chen, S.-H., Zhang, Y., Lagi, M., Chu, X., Liu, L., Faraone, A.,

Fratini, E., Baglioni, P., “The Dynamic Response Function 

XT(Q,t) of Confined Supercooled Water and its Relation

to the Dynamic Crossover Phenomenon,” Z. Phys. Chem.

224(1-2), 109 (2010). [CHRNS]
NCNR 2010 Accomplishments and Opportunities 67

Chen, W.C., Erwin, R., McIver III, J.W., Watson, S., Fu, C.B.,

Gentile, T.R., Borchers, J.A., Lynn, J.W., Jones, G.L.,

“Applications of 3He Neutron Spin Filters at the NCNR,” 

Physica B 404(17), 2663 (2009). [CHRNS]

Chen, Y.-S., Peng, H., “Studying the Water Transport in a Proton

Exchange Membrane Fuel Cell by Neutron Radiography 

and Relative Humidity Sensors,” J. Fuel Cell Sci. Technol. 6, 

031016-1 (2009).

Choi, S.-H., Lodge, T.P., Bates, F.S., “Mechanism of Molecular 

Exchange in Diblock Copolymer Micelles: Hypersensitivity 

to Core Chain Length,” Phys. Rev. Lett. 104(4), 047802-1 

(2010).

Chu, X.-Q., Lagi, M., Mamontov, E., Fratini, E., Baglioni, P., Chen,

S.-H., “Experimental Evidence of Logarithmic Relaxation in 

Single-Particle Dynamics of Hydrated Protein Molecules,” 

Soft Matter 6, 2623 (2010). [CHRNS]

Chung, J.-H., Ohgushi, K., Ueda, Y., “Magnetic Phase Diagrams 

of the Multicritical Olivine Mn2SiS4 and Mn2GeS4,” J. Magn. 

Magn. Mater. 322, 832 (2010).

Ciezak, J.A., Jenkins, T.A., Hemley, R.J., “Optical and Raman

Microspectroscopy of Nitrogen and Hydrogen Mixtures 

at High Pressures,” in “Shock Compression of Condensed 

Matter 2009: Proceedings of the American Physical Society 

Topical Group on Shock Compression of Condensed Matter,” 

edited by Elert, M., Furnish, M. D., Anderson, W.W., Proud,

W.G., and Butler, W.T., (AIP Conf. Proc., June 2009, Knoxville,

TN) 1195, 1291 (2009). 

Ciezak, J.A., Trevino, S.F., “Analysis of the Vibrational Spectrum

of Dihydrazinium 5,5’-Azotetrazolate Dihydrate by

Electronic Structure Calculations,” J. Mol. Struct. 975, 23 

(2010).

Cizas, P., Budvytyte, R., Morkuniene, R., Moldovan, R., Broccio,

M., Lösche, M., Niaura, G., Valincius, G., Borutaite, V., 

“Size-Dependent Neurotoxicity of β-Amyloid Oligomers,” 

Arch. Biochem. Biophys. 496(2), 84 (2010).

Clover, B., Hammouda, B., “SANS from P85/Water-d Under

Pressure,” Langmuir 26(9), 6625 (2010). [CHRNS]

Coffey, D., DeMarco, M., Ho, P.C., Maple, M.B., Sayles, T., 

Lynn, J.W., Huang, Q., Toorongian, S., Haka, M., “Absence of

the Hyperfine Magnetic Field at the Ru Site in Ferromagnetic

Rare-Earth Intermetallics,” Phys. Rev. B 81(18), 184404-1 

(2010).

Cooper, R.L., Bass, C.D., Beise, E.J., Breuer, H., Byrne, J., Chupp, 

T.E., Coakley, K.J., Dewey, M.S., Fisher, B.M., Fu, C., Gentile, 

T.R., McGonagle, M., Mumm, H.P., Nico, J.S., Thompson, 

A.K., Wietfeldt, F.E., “An Experiment for the Precision

Measurement of the Radiative Decay Mode of the Neutron,” 

Nucl. Instrum. Meth. A 611, 219 (2009).

Cooper, R.L., Chupp, T.E., Dewey, M.S., Gentile, T.R., 

Mumm, H.P., Nico, J.S., Thompson, A.K., Fisher, B.M., 

Kremsky, I., Wietfeldt, F.E., Beise, E.J., Kiriluk, K.G.,

Byrne, J., Coakley, K.J., Fu, C., “Radiative β Decay of the 

Free Neutron,” Phys. Rev. C 81(3), 035503-1 (2010).

Crompton, K.E., Forsythe, J.S., Horne, M.K., Finkelstein, 

D.I., Knott, R.B., “Molecular Level and Microstructural 

Characterisation of Thermally Sensitive Chitosan 

Hydrogels,” Soft Matter 5(23), 4704 (2009).

Cross, J.O., Newville, M., Maranville, B.B., Bordel, C., Hellman, 

F., Harris, V.G., “Evidence for Nanoscale Two-Dimensional 

Co Clusters in CoPt3 Films with Perpendicular Magnetic 

Anisotropy,” J. Phys.: Condens. Matter 22, 146002 (2010).

Das, N.C., Upreti, S., Sokol, P.E., “Small Angle Neutron Scattering 

and Photoluminescence Property of Wet Chemistry Process

Synthesised ZnO Nanoparticles,” J. Exp. Nanosci. 5(2), 180 

(2010).

Das, N.C., Sokol, P.E., “Hybrid Photovoltaic Devices from 

Regioregular Polythiophene and ZnO Nanoparticles

Compsites,” Renewable Energy , in press.

Das, P., O’Brien, T., Laver, M., Dewhurst, C.D., Ni, N., Bud’ko, 

S.L., Canfield, P.C., Eskildsen, M.R., “Small- Angle

Neutron Scattering Study of Vortices in Superconducting 

Ba(Fe0.93Co0.07)2As2,” Supercond. Sci. Technol. 23, 054007 

(2010). [CHRNS]

Davey, J.R., Mukundan, R., Spendelow, J.S., Mukherjee, P.P., 

Hussey, D.S., Jacobson, D.L., Arif, M., Borup, R., “Wetting

and Drying Responses of Gas Diffusion Layers and Proton 

Exchange Membrane to Current Transients,” ECS Trans. 

25(1), 971 (2009).

de la Cruz, C., Hu, W.Z., Li, S., Huang, Q., Lynn, J.W., Green,

M.A., Chen, G.F., Wang, N.L., Mook, H.A., Si, Q., Dai, P.,

“Lattice Distortion and Magnetic Quantum Phase Transition

in CeFeAs1-xPxO,” Phys. Rev. Lett. 104(1), 017204-1 (2010).

Decker, J.E., Walker, A.R.H., Bosnick, K., Clifford, C.A., Dai, L.,

Fagan, J., Hooker, S., Jakubek, Z.J., Kingston, C., Maker, J.,

Mansfield, E., Postek, M.T., Simard, B., Sturgeon, R., Wise,

S., Vladar, A.E., Yang, L., Zeisler, R., “Sample Preparation

Protocols for Realization of Reproducible Characterization of

Single-Wall Carbon Nanotubes,” Metrologia 46, 682 (2009).

Dennis, C.L., Jackson, A.J., Borchers, J.A., Hoopes, P.J., 

Strawbridge, R., Foreman, A.R., van Lierop, J., Grüttner, 

C., Ivkov, R., “Nearly Complete Regression of Tumors 

via Collective Behavior of Magnetic Nanoparticles in 

Hyperthermia,” Nanotechnology 20, 395103 (2009). [CHRNS]

Dewey, M.S., Gilliam, D.M., Nico, J.S., Greene, G.L., Laptev, A., 

Yue, A., “Measuring 6Li(n,t) and 10B(n,α) Cross Sections 

Using the NIST Alpha-Gamma Device,” in “Reactor 

Dosimetry State of the Art 2008,” edited by Voorbraak, W.,

Debarberis, L., D’hondt, P., and Wagemans, J., (13th ASTEMEWGRD, May 2008, Akersloot, Netherlands), 483 (2009).

Dewey, M., Coakley, K., Gilliam, D., Greene, G., Laptev, A., Nico, 

J., Snow, W., Wietfeldt, F., Yue, A., “Prospects for a New Cold

Neutron Beam Measurement of the Neutron Lifetime,” Nucl. 

Instrum. Meth. A 611, 189 (2009).

Diallo, S.O., Azuah, R.T., Kirichek, O., Taylor, J.W., Glyde, H.R.,

“Limits on Bose-Einstein Condensation in Confined Solid 4He,” Phys. Rev. B 80(6), 060504-1 (2009).
68Publications

Doe, C., Jang, H.-S., Kline, S.R., Choi, S.-M., “SANS 

Investigation of Selectively Distributed Single-Walled

Carbon Nanotubes in a Polymeric Lamellar Phase,” 

Macromol. 43, 5411 (2010).

Doe, C., Jang, H.-S., Kim, T.-H., Kline, S.R., Choi, S.-M., 

“Thermally Switchable One-and Two-Dimensional 

Arrays of Single-Walled Carbon Nanotubes in a

Polymeric System,” J. Am. Chem. Soc. 131, 16568 

(2009).

Domach, M.M., Walker, L.M., “Stabilizing BioMacromol. in

Nontoxic Nano-Structured Materials,” JALA 15(2), 136 

(2010). [CHRNS]

Dowling, M.B., Lee, J.-H., Raghavan, S.R., “pH-Responsive 

Jello: Gelatin Gels Containing Fatty Acid Vesicles,” 

Langmuir 25(15), 8519 (2009).

Eberle, A.P.R., Wagner, N.J., Akgun, B., Satija, S.K.,

“Temperature-Dependent Nanostructure of an 

End-Tethered Octadecane Brush in Tetradecane and 

Nanoparticle Phase Behavior,” Langmuir 26(5), 3003 

(2010). [CHRNS]

Ehlers, G., Greedan, J.E., Stewart, J.R., Rule, K.C., Fouquet, 

P., Cornelius, A.L., Adriano, C., Pagliuso, P.G., Qiu,

Y., Gardner, J.S., “High Resolution Neutron Scattering 

Study of Tb2Mo2O7: A Geometrically Frustrated Spin 

Glass,” Phys. Rev. B 81(22), 224405-1 (2010). [CHRNS]

ElMassalami, M., Moreno, R., Takeya, H., Ouladdiaf, B., 

Lynn, J.W., Freitas, R.S., “Magnetic Structures of

Quaternary Intermetallic Borocarbides RCo2B2C 

(R=Dy, Ho, Er),” J. Phys.: Condens. Matter 21, 436006 

(2009).

Ell, J.R., Mulder, D.E., Faller, R., Patten, T.E., Kuhl, T.L., 

“Structural Determination of High Density, ATRP 

Grown Polystyrene Brushes by Neutron Reflectivity,”

Macromol. 42, 9523 (2009).

Ferguson, P.P., Todd, A.D.W., Dahn, J.R., “Importance

of Nanostructure for High Capacity Negative 

Electrode Materials for Li-ion Batteries,” Electrochem. 

Commun., in press.

Fratini, E., Faraone, A., Todea, A.M., Baglioni, P., 

“Hydrated {Mo72Fe30} Clusters: Low-Frequency 

Hydrogen Modes and Self-Aggregation,” Inorganica 

Chimica Acta., in press. [CHRNS]

Fredin, N.J., Berry, B.C., Yager, K.G., Karim, A., Satija, S.K., 

Pickel, D.L., Jones, R.L., “Application of Thermal 

Gradients to Achieve Orientational Order in Block 

Copolymer Thin Films,” in “238th ACS National 

Meeting & Exposition, Fall 2009, Division of Polymer 

Materials: Science & Engineering,” edited by 

unknown, (ACS, Fall National Meeting & Exposition 

2009 Conf. Proc., August 2009, Washington, D.C.) 101, 

791 (2009).

Fu, R.S., Preston, J.S., Pasaogullari, U., Tabuchi, Y., Shiomi, T., 

Hussey, D.S., Jacobson, D.L., “An Investigation of ThermallyInduced Water Transport in Polymer Electrolyte Fuel Cells

with Neutron Radiography Imaging Technique,” in “Proton 

Exchange Membrane Fuel Cells 9,” edited by Fuller, T., 

Hartnig, C., Ramani, V., Uchida, H., Gasteiger, H., Cleghorn, 

S., Strasser, P., Zawodzinski, T., Jones, D., Shirvanina, P.,

Jarvi, T., Zelenay, P., Lamy, C., and Bele, P., (216th ECS

Meeting, October 2009, Vienna, Austria) 25(1), 543 (2009).

Fullerton-Shirey, S.K., Maranas, J.K., “Structure and Mobility of 

PEO/LiClO4 Solid Polymer Electrolytes Filled with Al2O3

Nanoparticles,” J. Phys. Chem. C. 114, 9196 (2010). [CHRNS]

Garcia Sakai, V., Mamontov, E., Neumann, D.A., “A Background 

Suppression Chopper for the High-Flux Backscattering 

Spectrometer at NIST,” J. Neutron Res. 16(3&4), 65 (2008). 

[CHRNS]

Gardner, J.S., Ehlers, G., “Magnetic Order and Crystal Field 

Excitations in Er2Ru2O7: A Neutron Scattering Study,” 

J. Phys.: Condens. Matter 21, 436004 (2009).

Gardner, J.S., Gingras, M.J.P., Greedan, J.E., “Magnetic Pyrochlore 

Oxides,” Rev. Mod. Phys. 82(1), 53 (2010). [CHRNS]

Gardner, J.S., Stewart, J.R., Ehlers, G., “Phase Separation in 

the Heisenberg Spin System, Gd2Ti2O7,” in “Neutron and 

X-Ray Scattering in Advancing Materials Research” edited

by Mohamed, B., and Aziz, A., (AIP Conf. Proc., June 2009,

Kuala Lumpur, Malaysia) 1202, 3 (2010).

Gardner, J.S., Kam, K.C., Ehlers, G., “New Relaxation Processes in 

Diluted Ho2Ti2O7,” Physica B 405, 774 (2010). [CHRNS]

Geissler, E., Hecht, A.-M., Horkay, F., “Scaling Behavior of 

Hyaluronic Acid in Solution with Mono- and Divalent Ions,” 

Macromol. Symp. 291-292, 362 (2010). [CHRNS]

Gentile, T.R., Brown, S.W., Lykke, K.R., Shaw, P.S., Woodward,

J.T., “Internal Quantum Efficiency Modeling of Silicon

Photodiodes,” Appl. Opt. 49(10), 1859 (2010).

Gericke, M., Page, S., Ramsay, D., Alarcon, R., Balascuta, S., 

Barron, L., Bowman, J.D., Carlini, R.D., Chen, W., Chupp,

T.E., Crawford, C., Covrig, S., Dabaghyan, M., Freedman, 

S.J., Gentile, T.R., Gillis, R.C., Greene, G.L., Hersman, F.W.,

Ino, T., Jones, G.L., Lauss, B., Leuschner, M., Losowki, B., 

Mahurin, R., Masuda, Y., Mei, J., Mitchell, G.S., Muto, S., 

Nann, H., Penttila, S.I., Salas-Bacci, A., Santra, S., Seo, P.-N., 

Sharapov, E., Sharma, M., Smith, T., Snow, W.M., Wilburn,

W.S., Yuan, V., “Parity Violation in Neutron-Proton Capture

- The NPDGamma Experiment,” Nucl. Instrum. Meth. A 611, 

239 (2009).

Gilliam, D.M., Yue, A.T., Dewey, M.S., “Calibration of a 

Manganese Bath Relative to 252CF Nu-Bar,” in “Reactor 

Dosimetry State of the Art 2008,” edited by Voorbraak, W.,

Debarberis, L., D’hondt, P., and Wagemans, J., (13th ASTEMEWGRD, May 2008, Akersloot, Netherlands), 361 (2009).

Gnäupel-Herold, T.H., “Techniques for Neutron Stress 

Determination with High Spatial Resolution,” 

J. Nondestruct. Eval. 28, 149 (2009).
NCNR 2010 Accomplishments and Opportunities 69

Gogotsi, Y., Portet, C., Osswald, S., Simmons, J.M., Yildirim, 

T., Laudisio, G., Fischer, J.E., “Importance of Pore Size in

High-Pressure Hydrogen Storage by Porous Carbons,” Int. J. 

Hydrogen Energy 34(15), 6314 (2009).

Green, M.A., “Surface Attraction,” Nat. Mater. 9, 539 (2010).

Grünwald, A.T.D., Wildes, A.R., Schmidt, W., Tartakovskaya,

E.V., Kwo, J., Majkrzak, C.F., Ward, R.C.C., Schreyer, A.,

“Magnetic Excitations in Dy/Y Superlattices as Seen via 

Inelastic Neutron Scattering,” Phys. Rev. B 82(1), 014426-1 

(2010).

Hadjiantoniou, N.A., Krasia-Christoforou, T., Loizou, E., Porcar,

L., Patrickios, C.S., “Alternating Amphiphilic Multiblock 

Copolymers: Controlled Synthesis via RAFT Polymerization

and Aqueous Solution Characterization,” Macromol. 43, 2713 

(2010). [CHRNS]

Hammouda, B., “The Mystery of Clustering in Macromolecular 

Media,” Polymer 50, 5293 (2009). [CHRNS]

Hammouda, B., “Insight into the Denaturation Transition of 

DNA,” Int. J. Biol. Macromol. 45, 532 (2009). [CHRNS]

Hammouda, B., “A New Guinier-Porod Model,” J. Appl. 

Crystallogr., in press. [CHRNS]

Hammouda, B., “SANS from Polymers - Review of the Recent 

Literature,” Polym. Rev. 50(1), 14 (2010). [CHRNS]

Hao, J., Cheng, H., Butler, P., Zhang, L., Han, C.C., “Origin of

Cononsolvency, Based on the Structure of TetrahydrofuranWater Mixture,” J. Chem. Phys. 132(15), 154902-1 (2010).

Harris, A.B., Yildirim, T., “Charge and Spin Ordering in the 

Mixed-Valence Compound LuFe2O4,” Phys. Rev. B 81(13), 

134417-41 (2010).

Hattrick-Simpers, J.R., Wang, K., Cao, L., Chiu, C., Heilweil, E.,

Downing, R.G., Bendersky, L.A., “Observation of Phase 

Transitions in Hydrogenated Yttrium Films via Normalized

Infrared Emissivity,” J. Alloys Compd. 490, 42 (2010).

He, C., El-Khatib, S., Eisenberg, S., Manno, M., Lynn, J.W.,

Zheng, H., Mitchell, J.F., Leighton, C., “Transport Signatures

of Percolation and Electronic Phase Homogeneity in 

La1-xSrxCoO3 Single Crystals,” Appl. Phys. Lett. 95(22), 

222511-1 (2009).

He, C., El-Khatib, S., Wu, J., Lynn, J.W., Zheng, H., Mitchell,

J.F., Leighton, C., “Doping Fluctuation-Driven MagnetoElectronic Phase Separation in La1-xSrxCoO3 Single Crystals,” 

Europhys. Lett. 87(2), 27006-p1 (2009).

He, L., Fujimoto, C.H., Cornelius, C.J., Perahia, D., “From 

Solutions to Membranes: Structure Studies of Sulfonated 

Polyphenylene Ionomers,” Macromol. 42, 7084 (2009). 

[CHRNS]

Helgeson, M.E., Hodgdon, T.K., Kaler, E.W., Wagner, N.J.,

“A Systematic Study of Equilibrium Structure, 

Thermodynamics, and Rheology of Aqueous CTAB/NaNO3

Wormlike Micelles,” J. Colloid Interface Sci. 349, 1 (2010).

Helgeson, M.E., Porcar, L., Lopez-Barron, C., Wagner, N.J., “Direct

Observation of Flow-Concentration Coupling in a ShearBanding Fluid,” Phys. Rev. Lett., in press. [CHRNS]

Helgeson, M.E., Reichert, M.D., Hu, Y.T., Wagner, N.J., “Relating

Shear Banding, Structure, and Phase Behavior in Wormlike

Micellar Solutions,” Soft Matter 5, 3858 (2009). [CHRNS]

Helton, J.S., Matan, K., Shores, M.P., Nytko, E.A., Bartlett, B.M., 

Qiu, Y., Nocera, D.G., Lee, Y.S., “Dynamic Scaling in the

Susceptibility of Spin-1⁄2 Kagome Lattice Antiferromagnet

Herbertsmithite,” Phys. Rev. Lett. 104(14), 147201-1 (2010). 

[CHRNS]

Her, J.-H., Zhou, W., Stavila, V., Brown, C.M., Udovic, T.J.,

“Crystal Structure of Na2B12H12 and the Role of Cation Size

on the Structural Behavior of the Alkali-Metal DodecahydroCloso-Dodecaborates,” in “ACS Division Proceedings, 

Division of Fuel Chemistry,” edited by unknown, (ACS, Fall 

National Meeting & Exposition 2009 Conf. Proc., August 

2009, Washington, D.C.) 54(2) (2009).

Hernandez, Y., Brown, C.M., “User Facilities: The Education of

New Neutron Users,” in “8th International Conference on 

Methods and Applications of Radioanalytical Chemistry: 

MARC-VIII,” edited by Ünlü, K., Heller-Zeisler, S., and

Zeisler, R. (AIP Conf. Proc, April 2009, Kona, HI,) 1164(1), 

52 (2009).

Herrera, A.P., Barrera, C., Zayas, Y., Rinaldi, C., “Monitoring

Colloidal Stability of Polymer-Coated Magnetic 

Nanoparticles using AC Susceptibility Measurements,” 

J. Colloid Interface Sci. 342, 540 (2010). [CHRNS]

Heuser, B.J., Ju, H., Trinkle, D.R., Udovic, T.J., “Hydrogen 

Trapping at Dislocations in Palladium at Low Temperature: 

Results From Inelastic Neutron Scattering and Advanced 

Computations,” in “Effects of Hydrogen on Materials,” 

edited by Somerday, B., Sofronis, P., and Jones, R., (ASM 

International Hydrogen 2008 Conference, September 2008, 

Grant Teton National Park, WY) 464 (2009).

Hickner, M.A., Hussey, D.S., “Neutron Radioscopy: Industrial 

and Scientific Applications,” in “Encyclopedia of Analytical

Chemistry,” edited by Meyers, R.A., (Wiley, US) Chap. on

Nuclear Methods (2010).

Hickner, M.A., Siegel, N.P., Chen, K.S., Hussey, D.S., Jacobson, 

D.L., “Observations of Transient Flooding in a Proton 

Exchange Membrane Fuel Cell Using Time-Resolved 

Neutron Radiography,” J. Electrochem. Soc. 157(1), B32 

(2010).

Hong, T., Custelcean, R., Sales, B.C., Roessli, B., Singh, D.K., 

Zheludev, A., “Synthesis and Structural Characterization of

2Dioxane•2H2O• CuCl2: Metal-Organic Compound with 

Heisenberg Antiferromagnetic S= 1⁄2 Chains,” Phys. Rev. B

80(13), 132404-1 (2009). [CHRNS]

Horkay, F., Magda, J., Alcoutlabi, M., Atzet, S., Zarembinski, T.,

“Structural, Mechanical and Osmotic Properties of Injectable 

Hyaluronan-Based Composite Hydrogels,” Polymer , in 

press. [CHRNS]
70Publications

Horkay, F., Basser, P.J., Hecht, A.-M., Geissler, E., 

“Counterion and pH-Mediated Structural Changes 

in Charged Biopolymer Gels,” Macromol. Symp. 291-

292, 354 (2010). [CHRNS]

Hould, N.D., Kumar, S., Tsapatsis, M., Nikolakis, V., Lobo, 

R.F., “Structure and Colloidal Stability of Nanosized

Zeolite Beta Precursors,” Langmuir 26(2), 1260 (2010). 

[CHRNS]

Huang, S.X., Chien, C.L., Thampy, V., Broholm, C., “Control

of Tetrahedral Coordination and Superconductivity 

in FeSe0.5Te0.5 Thin Films,” Phys. Rev. Lett. 104(21), 

271002-1 (2010).

Huang, S.-L., Hsu, Y.-C., Wu, C.-M., Lynn, J.W., Hsien,

W.-H., “Thermal Effects on the Activity and Structural

Conformation of Catechol 2,3-Dioxygenase from 

Pseudomonas Putida SH1,” J. Phys. Chem. B 114, 987 

(2010).

Huber, M.G., Wietfeldt, F.E., Gentile, T.R., Chen, W.C.,

Arif, M., Hussey, D.A., Pushin, D.A., Yang, L., Black, 

T., “Precision Measurement of the Neutron-3He 

Spin- Dependent Scattering Length using Neutron 

Interferometry,” Nucl. Instrum. Meth. A 611, 235 

(2009).

Huber, M.G., Arif, M., Black, T.C., Chen, W.C., Gentile,

T.R., Hussey, D.S., Pushin, D.A., Wietfeldt, F.E.,

Yang, L., “Erratum: Precision Measurement of the 

n-3He Incoherent Scattering Length Using Neutron 

Interferometry,” Phys. Rev. Lett. 103(17), 179903-1 

(2009).

Hule, R.A., Nagarkar, R.P., Hammouda, B., Schneider, 

J.P., Pochan, D.J., “Dependence of Self-Assembled 

Peptide Hydrogel Network Structure on Local Fibril 

Nanostructure,” Macromol. 42, 7137 (2009). [CHRNS]

Hussey, D.S., Jacobson, D.L., “In Situ Neutron Imaging of 

Alkaline and Lithium Batteries,” ECS Transactions 

25(35), 75 (2009).

Hussey, D.S., Jacobson, D.L., Arif, M., Coakley, K.J., 

Vecchia, D.F., “In Situ Fuel Cell Water Metrology at

the NIST Neutron Imaging Facility,” J. Fuel Cell Sci. 

Technol. 7, 021024-1 (2010).

Hussey, D.S., Jacobson, D.L., “High-Resolution Neutron 

Radiography Analysis of Proton Exchange Membrane 

Fuel Cells,” in “Modern Aspects of Electrochemistry, 

Vol. 49: Modeling and Diagnostics of Polymer 

Electrolyte Fuel Cells,” edited by Pasaogullari, U. and 

Wang, C.-Y., (Springer) Chap. 5, 175 (2010).

Iannuzzi, M.A., Reber, III, R., Lentz, D.M., Zhao, J., Ma, L.,

Hedden, R.C., “USANS Study of Porosity and Water

Content in Sponge-like Hydrogels,” Polymer 51, 2049 

(2010). [CHRNS]

Inosov, D.S., Shapoval, T., Neu, V., Wolff, U., White, J.S., Haindl,

S., Park, J.T., Sun, D.L., Lin, C.T., Forgan, E.M., Viazovska,

M.S., Kim, J.H., Laver, M., Nenkov, K., Khvostikova, O., 

Kühnemann, S., Hinkov, V., “Symmetry and Disorder of 

the Vitreous Vortex Lattice in Overdoped BaFe2-xCoxAs2: 

Indication for Strong Single-Vortex Pinning,” Phys. Rev. B 

81(1), 014513-1 (2010). [CHRNS]

Inoue, R., Kanaya, T., Nishida, K., Tsukushi, I., Telling, M.T.F., 

Gabrys, B.J., Tyagi, M., Soles, C., Wu, W.-l., “Glass Transition

and Molecular Mobility in Polymer Thin Films,” Phys. Rev. 

E. 80(3), 031802-1 (2009). [CHRNS]

Ivancic, T.M., Hwang, S.-J., Bowman, Jr., R.C., Birkmire, D.S., 

Jensen, C.M., Udovic, T.J., Conradi, M.S., “Discovery of a 

New Al Species in Hydrogen Reactions of NaAlH4,” J. Phys. 

Chem. Lett. 1, 2412 (2010).

Janssen, Y., Kim, M.S., Park, K.S., Wu, L.S., Marques, C., Bennett,

M.C., Chen, Y., Li, J., Huang, Q., Lynn, J.W., Aronson, M.C.,

“Determination of the Magnetic Structure of Yb3Pt4:k=0

Local-Moment Antiferromagnet,” Phys. Rev. B. 81(6), 

064401-1 (2010).

Jeong, Y., Chung, T.C.M., “The Synthesis and Characterization of

a Super-Activated Carbon Containing Subsitutional Boron 

(BCx) and its Applications in Hydrogen Storage,” Carbon, 

in press.

Ji, S., Kan, E.J., Whangbo, M.-H., Kim, J.-H., Qiu, Y., Matsuda, M.,

Yoshida, H., Hiroi, Z., Green, M.A., Ziman, T., Lee, S.-H.,

“Orbital Order and Partial Electronic Delocalization in a

Triangular Magnetic Metal Ag2MnO2,” Phys. Rev. B 81(9), 

094421-1 (2010). [CHRNS]

Jia, S., Chi, S.X., Lynn, J.W., Cava, R.J., “Magnetic and Structural

Properties of Ca(Fe1-xCox)2P2 and Ca(Ni1-xCox)2P2,” Phys. 

Rev. B 81(21), 214446-1 (2010).

Johnson, M.E., Malardier-Jugroot, C., Head-Gordon, T., “Effects 

of Co-Solvents on Peptide Hydration Water Structure and

Dynamics,” Phys. Chem. Chem. Phys. 12, 393 (2010). [CHRNS]

Jones, B.H., Lodge, T.P., “High-Temperature Nanoporous 

Ceramic Monolith Prepared from a Polymeric Bicontinuous 

Microemulsion Template,” J. Am. Chem. Soc. 131, 1676 

(2009).

Jones, C.Y., Nevers, T.J., “Temperature-Dependent Distortions of 

the Host Structure of Propylene Oxide Clathrate Hydrate,” 

J. Phys. Chem. C 114, 4194 (2010).

Junghans, A., Köper, I., “Structural Analysis of Tethered Bilayer 

Lipid Membranes,” Langmuir 26(13), 11035 (2010).

Kadowaki, H., Doi, N., Aoki, Y., Tabata, Y., Sato, T.J., Lynn, 

J.W., Matsuhira, K., Hiroi, Z., “Observation of Magnetic

Monopoles in Spin Ice,” J. Phys. Soc. Jpn. 78(10), 103706 

(2009).

Kalman, D.P., Wagner, N.J., “Microstructure of Shear-Thickening

Concentrated Suspensions Determined by Flow-USANS,” 

Rheol. Acta 48(8), 897 (2009). [CHRNS]
NCNR 2010 Accomplishments and Opportunities 71

Kamazawa, K., Harada, M., Ikedo, Y., Sugiyama, J., Tyagi, M.,

Matsuo, Y., “Long Range Proton Diffusive Motion of CsHSO4

and CsHSeO4: - High Energy Resolution Quasielastic

Neutron Scattering of Superprotonic Conductors-,” J. Phys. 

Soc. Jpn. 79, 7 (2010). [CHRNS]

Kang, S., Wu, W.-l., Choi, K.-W., De Silva, A., Ober, C.K.,

Prabhu, V.M., “Characterization of the Photoacid Diffusion

Length and Reaction Kinetics in EUV Photoresists with IR 

Spectroscopy,” Macromol. 43, 4275 (2010).

Kawabata, Y., Nagao, M., “Neutron Spin Echo Studies on 

Dynamical Structures of Microemulsion,” Hamon 20(1), 

80 (2010).

Kealley, C.S., Sokolova, A.V., Kearley, G.J., Kemner, E., Russina, 

M., Faraone, A., Hamilton, W.A., Gilbert, E.P., “Dynamical

Transition in a Large Globular Protein: Macroscopic 

Properties and Glass Transition,” Biochim. Biophys. Acta. 

1804, 34 (2010). [CHRNS]

Kent, B., Garvey, C.J., Lenné, T., Porcar, L., Garamus, V.M., Bryant, 

G., “Measurement of Glucose Exclusion from the Fully 

Hydrated DOPE Inverse Hexagonal Phase,” Soft Matter 6, 

1197 (2010).

Kent, M.S., Murton, J.K., Sazaki, D.Y., Satija, S., Akgun, B., Nanda

H., Curtis, J.E., Majewski, J., Morgan, C.R., Engen, J.R., 

“Neutron Reflectometry Study of the Conformation of HIV

Nef Bound to Lipid Membranes,” Biophys. J., in press.

Khan, A.S., Meredith, C.S., “Thermo-Mechanical Response of 

Al 6061 with and without Equal Channel Angular Pressing 

(ECAP),” Int. J. Plast. 26, 189 (2010).

Khodadadi, S., Roh, J.H., Kisliuk, A., Mamontov, E., Tyagi, M., 

Woodson, S.A., Briber, R.M., Sokolov, A.P., “Dynamics

of Biological Macromolecules: Not a Simple Slaving by 

Hydration Water,” Biophys. J. 98, 1321 (2010). [CHRNS]

Kiel, J.W., Kirby, B.J., Majkrzak, C.F., Maranville, B.B., Mackay,

M.E., “Nanoparticle Concentration Profile in Polymer-based

Solar Cells,” Soft Matter 6, 641 (2010).

Kiel, J.W., Mackay, M.E., Kirby, B.J., Maranville, B.B., Majkrzak,

C.F., “Phase-Sensitive Neutron Reflectometry Measurements

Applied in the Study of Photovoltaic Films,” J. Chem. Phys., 

in press.

Kienzle, P.A., Patel, N., McKerns, M., “Parallel Kernels: An

Architecture for Distributed Parallel Computing,” in 

“Proceedings of the 8th Python in Science Conference 

(SciPy2009),” edited by Varoquaux, G., van der Walt, S.,

and Millman, K.J., (SciPy2009, August 2009, Pasadena, CA), 

36 (2009).

Kilburn, D., Roh, J.H., Guo, L., Briber, R.M., Woodson, S.A.,

“Molecular Crowding Stabilizes Folded RNA Structure by

the Excluded Volume Effect,” J. Am. Chem. Soc. 132, 8690 

(2010).

Kim, S.-H., Halasyamani, P.S., Melot, B.C., Seshadri, R., Green, 

M.A., Sefat, A.S., Mandrus, D., “Experimental and 

Computational Investigation of the Polar Ferrimagnet 

VOSe2O5,” Chem. Mater., in press.

King, G., Woodward, P.M., “Cation Ordering in Perovskites,”

J. Mater. Chem. 20(28), 5785 (2010).

King, G., Garcia-Martin, S., Woodward, P.M., “Octahedral Tilt

Twinning and Compositional Modulation in NaLaMgWO6,” 

Acta Crystallogr. Sect. B: Struct. Sci. 65(6), 676 (2009).

Kiran, S.K., Acosta, E.J., “Predicting the Morphology and Viscosity 

of Microemulsions Using the HLD-NAC Model,” Ind. Eng. 

Chem. Res. 49, 3424 (2010).

Kirby, B.J., Davies, J.E., Liu, K., Watson, S.M., Zimanyi, G.T.,

Shull, R.D., Kienzle, P.A., Borchers, J.A., “Vertically Graded

Anisotropy in Co/Pd Multilayers,” Phys. Rev. Lett. 81(10), 

100405-1 (2010).

Koga, T., Wong, J., Endoh, M.K., Mahajan, D., Gutt, C., Satija, S.K.,

“Hydrate Formation at the Methane/Water Interface on the

Molecular Scale,” Langmuir 26(7), 4627 (2010).

Kopetka, P., Middleton, M., Williams, R.E., Rowe, J.M., “A Second

Liquid Hydrogen Cold Source for the NIST Reactor,” in 

“Proceedings of the 12th Meeting of the International Group 

on Research Reactors,” (IGORR-12, October 2009, Beijing, 

China) in press.

Krepkiy, D., Mihailescu, M., Freites, J.A., Schow, E.V., Worcester,

D.L., Gawrisch, K., Tobias, D.J, White, S.H., Swartz, K.J.,

“Structure and Hydration of Membranes Embedded with 

Voltage-Sensing Domains,” Nature 462, 473 (2009).

Krycka, K.L., Booth, R.A., Hogg, C.R., Ijiri, Y., Borchers, J.A., 

Chen, W.C., Watson, S.M., Laver, M., Gentile, T.R., Dedon,

L.R., Harris, S.A., Rhyne, J.J., Majetich, S.A., “Core-Shell 

Magnetic Morphology of Structurally Uniform Magnetite 

Nanoparticles,” Phys. Rev. Lett. 104(20), 207203-1 (2010). 

[CHRNS]

Krycka, K.L., Borchers, J.A., Booth, R.A., Hogg, C.R., Ijiri, Y., 

Chen, W.C., Watson, S.M., Laver, M., Gentile, T.R., Harris, S.,

Dedon, L.R., Rhyne, J.J., Majetich, S.A., “Internal Magnetic 

Structure of Magnetite Nanoparticles at Low Temperature,” 

J. Appl. Phys. 107(9), 09B525-1 (2010). [CHRNS]

Krycka, K.L., Booth, R., Borchers, J.A., Chen, W.C., Conlon, C.,

Gentile, T.R., Hogg, C., Ijiri, Y., Laver, M., Maranville, B.B., 

Majetick, S.A., Rhyne, J.J., Watson, S.M., “Resolving 3D

Magnetism in Nanoparticles Using Polarization Analyzed

SANS,” Physica B 404(17), 2561 (2009). [CHRNS]

Kumar, N., Chi, S.X., Chen, Y., Rana, K.G., Nigam, A.K.,

Thamizhavel, A., Ratcliff, II, W., Dhar, S.K., Lynn, J.W.,

“Evolution of the Bulk Properties, Structure, Magnetic Order, 

and Superconductivity with Ni Doping in CaFe2-xNixAs2,” 

Phys. Rev. B 80(14), 144524-1 (2009).

Kumar, R., Raghavan, S.R., “Thermothickening in Solutions 

of Telechelic Associating Polymers and Cyclodextrins,” 

Langmuir 26(1), 56 (2010). [CHRNS]

Kumar, R., Ketner, A.M., Raghavan, S.R., “Nonaqueous 

Photorheological Fluids Based on Light-Responsive Reverse 

Wormlike Micelles,” Langmuir 26(8), 5405 (2010).
72Publications

Lam, V.D., Walker, L.M., “A pH-Induced Transition

of Surfactant-Polyelectrolyte Aggregates from 

Cylindrical to String-of-Pearls Structure,” Langmuir 

26(13), 10489 (2010). [CHRNS]

Larson-Smith, K., Jackson, A., Pozzo, D.C., “Small Angle

Scattering Model for Pickering Emulsions and 

Raspberry Particles,” J. Colloid Interface Sci. 343, 36 

(2010). [CHRNS]

Lauw, Y., Rodopoulos, T., Gross, M., Nelson, A., Gardner, 

R., Horne, M.D., “Electrochemical Cell for Neutron 

Reflectometry Studies of the Structure of Ionic Liquids

at Electrified Interface,” Rev. Sci. Instrum. 81(7), 

074101-1 (2010).

Laver, M., Mudivarthi, C., Cullen, J.R., Flatau, A.B., Chen, 

W.-C., Watson, S.M., Wuttig, M., “Magnetostriction

and Magnetic Heterogeneities in Iron-Gallium,” Phys. 

Rev. Lett. 105(2), 027202-1 (2010).

Lee, Jr., C.T., Smith, K.A., Hatton, T.A., “Small-Angle 

Neutron Scattering Study of the Micellization

of Photosensitive Surfactants in Solution and 

in the Presence of a Hydrophobically Modified

Polyelectrolyte,” Langmuir 25(24), 13784 (2009). 

[CHRNS]

Lee, H.-Y., Diehn, K.K., Ko, S.W., Tung, S.-H., Raghavan,

S.R., “Can Simple Salts Influence Self-Assembly in

Oil? Multivalent Cations as Efficient Gelators of

Lecithin Organosols,” Langmuir , in press. [CHRNS]

Lee, J.-H., Choi, S.-M., Doe, C., Faraone, A., Pincus, P.A., 

Kline, S.R., “Thermal Fluctuation and Elasticity 

of Lipid Vesicles Interacting with Pore-Forming 

Peptides,” Phys. Rev. Lett. 105(3), 038101-1 (2010). 

[CHRNS]

Lee, S.-H., Xu, G., Ku, W., Wen, J.S., Lee, C.C., Katayama,

N., Xu, Z.J., Ji, S., Lin, Z.W., Gu, G.D., Yang, H.-B.,

Johnson, P.D., Pan, Z.-H., Valla, T., Fujita, M., Sato, T.J.,

Chang, S., Yamada, K., Tranquada, J.M., “Coupling 

of Spin and Orbital Excitations in the Iron-Based 

Superconductor FeSe0.5Te0.5,” Phys. Rev. B 81(22), 

220502-1 (2010). [CHRNS]

Lee, W., Kofinas, P., Briber, R.M., “Small Angle

Neutron Scattering Study of Deuterated Sodium 

Dodecylsulfate Micellization in Dilute Poly((2-

dimethylamino)ethyl methacrylate) Solutions,” 

Polymer 51, 2872 (2010).

Levin, I., Karimi, S., Provenzano, V., Dennis, C.L., Wu,

H., Comyn, T.P., Stevenson, T.J., Smith, R.I., Reaney, 

I.M., “Reorientation of Magnetic Dipoles at the 

Antiferroelectric-Paraelectric Phase Transition of 

Bi1-xNdxFeO3 (0.15 ≤ x ≤ 0.25),” Phys. Rev. B 81(2), 

020103-1 (2010).

Li, J., Callaway, D.J.E., Bu, Z., “Ezrin Induces Long-Range

Interdomain Allostery in the Scaffolding Protein 

NHERF1,” J. Mol. Biol. 392, 166 (2009). [CHRNS]

Li, S.-L., Yao, D.-X., Qiu, Y.-m., Kang, H.J., Carlson, E.W., Hu, J.–P.,

Chen, G.-F., Wang, N.-L., Dai, P.-C., “Low-Energy Ce Spin

Excitations in CeFeAsO and CeFeAsO0.84F0.16,” Front. Phys. 

China 5(2), 161 (2010). [CHRNS]

Li, X., Shew, C.-Y., Liu, Y., Pynn, R., Liu, E., Herwig, K.W., Smith,

G.S., Robertson, J.L., Chen, W.-R., “Theoretical Studies on the

Structure of Interacting Colloidal Suspensions by Spin-Echo 

Small Angle Neutron Scattering,” J. Chem. Phys. 132(17), 

174509-1 (2010).

Lin-Gibson, S., Chatterjee, K., Cooper, J.A., Wallace, W.E.,

Becker, M.L., Simon, Jr., C.G., Horkay, F., “PEG-Hydrogels: 

Synthesis, Characterization, and Cell Encapsulation,” in

“238th ACS National Meeting & Exposition,” edited by 

unknown, (ACS Fall National Meeting & Exposition, August 

2009 Washington, DC) (2009).

Lindstrom, R.M., “Errors, PGAA, and Metrology,” J. Radioanal. 

Nucl. Chem. 282, 5 (2009).

Lindstrom, R.M., “Routine Gamma-Ray Peak Integration: How 

Good Can It Be?,” Trans. Am. Nucl. Soc. 101, 99 (2009).

Lindstrom, R.M., Fischbach, E., Buncher, J.B., Greene, G.L., 

Jenkins, J.H., Krause, D.E., Mattes, J.J., Yue, A., “Study of the 

Dependence of 198Au Half-Life on Source Geometry,” Nucl. 

Instrum. Meth. A, in press.

Linegar, K.L., Adeniran, A.E., Kostko, A.F., Anisimov, M.A., 

“Hydrodynamic Radius of Polyethylene Glycol in Solution 

Obtained by Dynamic Light Scattering,” Colloid J. 72(2), 279 

(2010).

Linton, P., Rennie, A.R., Alfredsson, V., “Evolution of Structure 

and Composition During the Synthesis of Mesoporous Silica 

SBA-15 Studied by Small-Angle Neutron Scattering,” Solid 

State Sci., in press. [CHRNS]

Lister, S.E., Soleilhavoup, A., Withers, R.L., Hodgkinson, P., Evans,

J.S.O., “Structures and Phase Transitions in (MoO2)2P2O7,” 

Inorg. Chem. 49, 2290 (2010).

Liu, D.M., Huang, Q.Z., Yue, M., Lynn, J.W., Liu, L.J., Chen, Y.,

Wu, Z.H., Zhang, J.X., “Temperature, Magnetic Field, and

Pressure Dependence of the Crystal and Magnetic Structures 

of the Magnetocaloric Compound Mn1.1Fe0.9(P0.8Ge0.2),” 

Phys. Rev. B 80(17), 174415-1 (2009).

Liu, H.-T., Gnäupel-Herold, T., Hovanski, Y., Dahl, M.E., “Fatigue 

Performance Enhancement of AWJ-Machined Aircraft

Aluminum with Dry-Grit Blasting,” in “Proceedings for 

the 2009 American WJTA Conference and Expo,” edited by

Hashish, M., (AM WJTA Conf. Proc., August 2009, Houston,

TX). (2009).

Liu, L.J., Liu, D.M., Huang, Q.Z., Zhang, T.L., Zhang, L., Yue, M.,

Lynn, J.W., Zhang, J.X., “Neutron Diffraction Study of the

Magnetic Refrigerant Mn1.1Fe0.9P0.76Ge0.24,” Powder Diffr., 

in press.
NCNR 2010 Accomplishments and Opportunities 73

Liu, T.J., Hu, J., Qian, B., Fobes, D., Mao, Z.Q., Bao, W., Reehuis,

M., Kimber, S.A.J., Prokes, K., Matas, S., Argyriou, D.N., 

Hiess, A., Rotaru, A., Pham, H., Spinu, L., Qiu, Y., Thampy,

V., Savici, A.T., Rodriguez, J.A., Broholm, C., “From (π,O) 

Magnetic Order to Superconductivity with (π,π) Magnetic 

Resonance in Fe1.02Te1-xSex,” Nat. Mater., in press. [CHRNS]

Liu, Y., Porcar, L., Hong, K., Shew, C.-Y., Li, X., Liu, E., Butler, P.D.,

Herwig, K.W., Smith, G.S., Chen, W.-R., “Effect of Counterion

Valence on the pH Responsiveness of Polyamidoamine 

Dendrimer Structure,” J. Chem. Phys. 132(12), 124901-1 

(2010). [CHRNS]

Liu, Y., Chen, C.-Y., Chen, H.-L., Hong, K., Shew, C.-Y., Li, X., Liu,

L., Melnichenko, Y.B., Smith, G.S., Herwig, K.W., Porcar, L.,

Chen, W.-R., “Electrostatic Swelling and Conformational

Variation Observed in High-Generation Polyelectrolyte 

Dendrimers,” J. Phys. Chem. Lett. 1(13), 2020 (2010). [CHRNS]

Loizou, E., Porcar, L., Schexnailder, P., Schmidt, G., Butler, P.,

“Shear-Induced Nanometer and Micrometer Structural 

Responses in Nanocomposite Hydrogels,” Macromol. 43, 

1041 (2010). [CHRNS]

Lokitz, B.S., Messman, J.M., Hinestrosa, J.P., Alonzo, J., Verduzco,

R., Brown, R.H., Osa, M., Ankner, J.F., Kilbey, II, S. M., 

“Dilute Solution Properties and Surface Attachment of RAFT 

Polymerized 2-Vinyl-4,4-dimethyl Azlactone (VDMA),”

Macromol. 42, 9018 (2009). [CHRNS]

Long, Y.W., Huang, Q., Yang, L.X., Yu, Y., Lv, Y.X., Lynn, J.W.,

Chen, Y., Jin, C.Q., “Low-Temperature Neutron Diffraction

Study of the Crystal and Magnetic Phase Transitions in 

DyCrO4,” J. Magn. Magn. Mater. 322, 1912 (2010).

Louca, D., Kamazawa, K., Proffen, T., “Formation of Local Electric

Dipoles with No Unique Polar Axis in Tb3Fe5O12,” Phys. Rev. 

B 80(21), 214406-1 (2009). [CHRNS]

Lucas, G.E., “An Evolution of Understanding of Reactor Pressure 

Vessel Steel Embrittlement” J. Nucl. Mater., in press. [CHRNS]

Lumata, L.L., Besara, T., Kuhns, P.L., Reyes, A.P., Zhou, H.D.,

Wiebe, C.R., Balicas, L., Jo, Y.J., Brooks, J.S., Takano, Y., Case,

M.J., Qiu, Y., Copley, J.R.D., Gardner, J.S., Choi, K.Y., Dalal,

N.S., Hoch, M.J.R., “Low-Temperature Spin Dynamics in the 

Kagome System Pr3Ga5SiO14,” Phys. Rev. B 81(22), 224416-1 

(2010). [CHRNS]

Luzin, V., Prask, H.J., Gnäupel-Herold, T., Sampath, S., “Use of

Neutron Diffraction for Stress Measurements in Thin and 

Thick Thermal Sprayed Coatings,” Int. Heat Treat. Surf. Eng 

4(1), 17 (2010).

Luzin, V., Matejicek, J., Gnäupel-Herold, T.H., “ThroughThickness Residual Stress Measurement by Neutron 

Diffraction in Cu+W Plasma Spray Coatings,” Mater. Sci.

Forum 652, 50 (2010).

Lynn, J.W., “Iron Based Superconductors,” in “McGraw-Hill

Yearbook of Science and Technology 2010,” edited by 

unknown, (McGraw-Hill) 204 (2010).

Lynn, J.W., “Book review of Neutron Scattering in Condensed Matter 

Physics, by A. Furrer, et al.” Neutron News 21, 59 (2010).

Mackey, E.A., Paul, R.L., Spatz, R.O., Tomlin, B.E., Zeisler, R.,

“Quality Assurance in Homogeneity Assessment of Soil

Standard Reference Materials,” Trans. Am. Nucl. Soc. 101, 

114 (2009).

Mackey, E.A., Christopher, S.J., Lindstrom, R.M., Long, S.E., 

Marlow, A.F., Murphy, K.E., Paul, R.L., Popelka-Filcoff, R.S., 

Rabb, S.A., Sieber, J.R., Spatz, R.O., Tomlin, B.E., Wood, L.J.,

Yu, L.L., Zeisler, R., Yen, J.H., Wilson, S.A., Adams, M.G.,

Brown, Z.A., Lamothe, P.L., Taggart, J.E., Jones, C., Nebelsick,

J., “Certification of Three NIST Renewal Soil Standard

Reference Materials for Element Content: SRM 2709a San 

Joaquin Soil, SRM 2710a Montana Soil I, and SRM 2711a 

Montana Soil II,” NIST Special Publication 260-172, 2 (2010).

Mahabir, S., Wan, W., Katsaras, J., Nieh, M.-P., “Effects of Charge

Density and Thermal History on the Morphologies on 

Spontaneously Formed Unilamellar Vesicles,” J. Phys. Chem. 

B 114, 5729 (2010). [CHRNS]

Malardier-Jugroot, C., Bowron, D.T., Soper, A.K., Johnson, 

M.E., Head-Gordon, T., “Structure and Water Dynamics of

Aqueous Peptide Solutions in the Presence of Co-Solvents,” 

Phys. Chem. Chem. Phys. 12, 382 (2010). [CHRNS]

Mallamace, F., Branca, C., Corsaro, C., Leone, N., Spooren, J., 

Stanley, H.E., Chen, S.-H., “Dynamical Crossover and 

Breakdown of the Stokes-Einstein Relation in Confined

Water and in Methanol-Diluted Bulk Water,” J. Phys. Chem.

B 114, 1870 (2010). [CHRNS]

Mang, J.T., Hjelm, R.P., Francois, E.G., “Measurement of Porosity 

in a Composite High Explosive as a Function of Pressing 

Conditions by Ultra-Small-Angle Neutron Scattering with 

Contrast Variation,” Propellants Explos. Pyrotech. 35, 7 

(2010). [CHRNS]

Manson, J.L., Lancaster, T., Blundell, S.J., Qiu, Y., Singleton, J.,

Sengupta, P., Pratt, F.L., Kang, J., Lee, C., Whangbo, M.-

H., “Spin Gluctuations and Orbital Ordering in QuasiOne-Dimensional α-Cu(dca)2(pyz) {dca = Dicyanamide =

N(CN)2 -; pyz = Pyrazine}, a Molecular Analogue of KCuF3,” 

Polyhedron 29, 514 (2010). [CHRNS]

Marcus, M.S., Simmons, J.M., Baker, S.E., Hamers, R.J., Eriksson, 

M.A., “Predicting the Results of Chemical Vapor Deposition 

Growth of Suspended Carbon Nanotubes,” Nano Lett. 9(5), 

1806 (2009).

Marinenko, R.B., Turner, S., Simons, D.S., Rabb, S.A., Zeisler,

R.L., Yu, L.L., Newbury, D.E., Paul, R.L., Ritchie, N.W.M.,

Leigh, S.D., Winchester, M.R., Richter, L.J., Meier, D.C., Scott,

K.C.K., Klinedinst, D., Small, J.A., “Characterization of

SiGe Films for Use as a National Institute of Standards and 

Technology Microanalysis Reference Material (RM8905),” 

Microsc. Microanal. 16, 1 (2010).

Mason, P.E., Dempsey, C.E., Neilson, G.W., Kline, S.R., Brady, J.W.,

“Preferential Interactions of Guanidinum Ions with Aromatic 

Groups over Aliphatic Groups,” J. Am. Chem. Soc. 131, 16689 

(2009). [CHRNS]
74Publications

Matan, K., Ibuka, S., Morinaga, R., Chi, S.X., Lynn, J.W.,

Christianson, A.D., Lumsden, M.D., Sato, T.J., 

“Doping Dependence of Spin Dynamics in Electrondoped Ba(Fe1-xCox)2As2,” Phys. Rev. B, in press.

Mayumi, K., Nagao, M., Endo, H., Osaka, N., Shibayama, 

M., Ito, K., “Dynamics of Polyrotaxane Investigated 

by Neutron Spin Echo,” Physica B 404, 2600 (2009). 

[CHRNS]

Mayumi, K., Endo, H., Osaka, N., Yokoyama, H., Nagao, 

M., Shibayama, M., Ito, K., “Mechanically Interlocked 

Structure of Polyrotaxane Investigated by Contrast 

Variation Small-Angle Neutron Scattering,” 

Macromol. 42, 6327 (2009).

Mayumi, K., Ito, K., “Structure and Dynamics of 

Polyrotaxane and Slide-ring Materials,” Polymer 51, 

959 (2010). [CHRNS]

McMullan, J.M., Wagner, N.J., “Directed Self-Assembly

of Colloidal Crystals by Dielectrophoretic Ordering 

Observed with Small Angle Neutron Scattering 

(SANS),” Soft Matter , in press. [CHRNS]

Meli, L., Santiago, J.M., Lodge, T.P., “Path-Dependent 

Morphology and Relaxation Kinetics of Highly 

Amphiphilic Diblock Copolymer Micelles in Ionic 

Liquids,” Macromol. 43, 2018 (2010).

Melnichenko, Y.B., Mayama, H., Cheng, G., Blach, T., 

“Monitoring Phase Behavior of Sub- and Supercritical 

Co2 Confined in Porous Fractal Silica with 85%

Porosity,” Langmuir 26(9), 6374 (2010). [CHRNS]

Mikel, S.E., Biernacki, J.J., Gnäupel-Herold, T., “A Neutron 

Diffraction-Based Technique for Determining PhaseResolved Strains in Portland Cement,” ACI Mater. J. 

106(5), 455 (2009).

Mildner, D.F.R., Gubarev, M.V., “Wolter Optics for Neutron

Focusing,” Nucl. Instrum. Methods Phys. Res. A, in 

press.

Mirarefi, P., Lee, Jr., C.T., “Photo-Induced Unfolding and

Inactivation of Bovine Carbonic Anhydrase in the 

Presence of a Photoresponsive Surfactant,” Biochim. 

Biophys. Acta. 1804, 106 (2010).

Mrozek, R.A., Cole, P.J., Cole, S.M., Schroeder, J.L.,

Schneider, D.A., Hedden, R.C., Lenhart, J.L., 

“Design of Nonaqueous Polymer Gels with Broad 

Temperature Performance: Impact of Solvent Quality

and Processing Conditions,” J. Mater. Res. 25(6), 1105 

(2010).

Mudivarthi, C., Laver, M., Cullen, J., Flatau, A.B., Wuttig,

M., “Origin of Magnetostriction in Fe-Ga,” J. Appl. 

Phys. 107(9), 09A957-1 (2010). [CHRNS]

Mukherjee, P.P., Mukundan, R., Spendelow, J.S., Borup, 

R.L., Hussey, D.S., Jacobson, D.L., Arif, M., “High 

Resolution Neutron Imaging of Water in the Polymer

Electrolyte Fuel Cell Membrane,” ECS Trans. 25(1), 

505 (2009).

Mukundan, R., Lujan, R.W., Davey, J.R., Spendelow, J.S., Hussey,

D.S., Jacobson, D.L., Arif, M., Borup, R.L., “Ice Formation 

in PEM Fuel Cells Operated Isothermally at Sub-Freezing

Temperature,” ECS Trans. 25(1), 345 (2009).

Murray, L.J., Dinca, M., Yano, J., Chavan, S., Bordiga, S., Brown, 

C.M., Long, J.R., “Highly-Selective and Reversible O2

Binding in Cr3(1,3,5-Benzenetricarboxylate)2,” J. Am. Chem. 

Soc. 132, 7856 (2010).

Nagao, M., Seto, H., “Full Fitting Analysis of the Relative 

Intermediate Form Factor Measured by Neutron Spin Echo,” 

Physica B 404(17), 2603 (2009). [CHRNS]

Nagao, M., “Observation of Local Thickness Fluctuations in 

Surfactant Membranes using Neutron Spin Echo,” Phys. Rev. 

E. 80(3), 031606-1 (2009). [CHRNS]

Nagao, M., Kawabata, Y., Seto, H., “High-Pressure SANS and NSE 

Experiments in Microemulsion Systems,” Rev. High Pres. Sci. 

Tech. 19(1), 52 (2009).

Nakatsuji, S., Nambu, Y., Onoda, S., “Novel Geometrical 

Frustration Effects in the Two-Dimensional TriangularLattice Antiferromagnet NiGa2S4 and Related Compounds,” 

J. Phys. Soc. Jpn. 79(1), 011003-1 (2010).

Nanda, H., Datta, S.A.K., Heinrich, F., Losche, M., Rein, A., 

Krueger, S., Curtis, J.E., “Electrostatic Interactions and the 

Binding Orientation of HIV-1 Matrix Studied by Neutron 

Reflectivity,” Biophys. J., in press.

Nedoma, A.J., Lai, P., Jackson, A., Robertson, M.L., Wanakule,

N.S., Balsara, N.P., “Phase Behavior of Asymmetric 

Multicomponent A/B/A-C Blends with Unequal 

Homopolymer Molecular Weights,” Macromol. 43, 3549 

(2010). [CHRNS]

Nico, J.S., “Neutron Beta Decay,” J. Phys. G: Nucl. Part. Phys. 36, 

104001 (2009).

Obrzut, J., Page, K.A., “Electrical Conductivity and Relaxation in

Poly(3-hexylthiophene),” Phys. Rev. B 80(19), 195211-1 (2009). 

[CHRNS]

O’Shaughnessy, C.M., Golub, R., Schelhammer, K.W., Swank,

C.M., Seo, P.-N., Huffman, P.R., Dzhosyuk, S.N., Mattoni,

C.E.H., Yang, L., Doyle. J.M., Coakley, K.J., Thompson, 

A.K., Mumm, H.P., Lamoreaux, S.K., McKinsey, D.N., Yang, 

G., “Measuring the Neutron Lifetime using Magnetically 

Trapped Neutrons.” Nucl. Iustrum. Methods Phys. A 611, 

171 (2009).

Pabst, G., Kŭcerka, N., Nieh, M.P., Rheinstädter, M.C., Katsaras, J.,

“Applications of Neutron and X-ray Scattering to the Study

of Biologically Relevant Model Membranes,” Chem. Phys. 

Lipids 163, 460 (2010).

Pafiti, K.S., Loizou, E., Patricklos, C.S., Porcar, L., “End-Linked

Semifluorinated Amphiphilic Polymer Conetworks:

Synthesis by Sequential Reversible Addition-Fragmentation 

Chain Transfer Polymerization and Characterization,”

Macromol. 43, 5195 (2010).
NCNR 2010 Accomplishments and Opportunities 75

Park, J.K., Jones, P.J., Sahagun, C., Page, K.A., Hussey, D.S., 

Jacobson, D.L., Morgan, S.E., Moore, R.B., “Electrically 

Stimulated Gradients in Water and Counterion

Concentrations within Electroactive Polymer Actuators,” Soft 

Matter 6, 1444 (2010).

Park, M.J., Balsara, N.P., Jackson, A., “Order-Disorder Transitions 

in Block Copolymer Electrolytes at Equilibrium with Humid 

Air,” Macromol. 42, 6808 (2009). [CHRNS]

Paul, R.L., Hossain, T., Wu, L., Downing, R.G., “Determination of

Trace Boron in Bulk High-Purity Silicon,” Trans. Am. Nucl. 

Soc. 101, 112 (2009).

Paul, R.L., Mackey, E.A., Zeisler, R., Spatz, R.O., Tomlin, B.E.,

“Determination of Elements in SRM Soil 2709a by Neutron 

Activation Analysis,” J. Radioanal. Nucl. Chem. 282(3), 945 

(2009).

Peri, S.R., Kim, H., Akgun, B., Enlow, J., Jiang, H., Bunning, T.J., 

Li, X., Foster, M.D., “Structure of Copolymer Films Created

by Plasma Enhanced Chemical Vapor Deposition,” in press.

Peri, S.R., Habersberger, B., Akgun, B., Jiang, H., Enlow, J., 

Bunning, T.J., Majkrzak, C.F., Foster, M.D., “Variations in

Cross-link Density with Deposition Pressure in Ultrathin 

Plasma Polymerized Benzene and Octafluorocyclobutane

Films,” Polymer , in press.

Perriman, A.W., Williams, D.S., Jackson, A.J., Grillo, I., Koomullil,

J.M., Ghasparian, A., Robinson, J.A., Mann, S., “Synthetic 

Viruslike Particles and Hybrid Constructs Based on 

Lipopeptide Self-Assembly,” Small 6(11), 1191 (2010). [CHRNS]

Petorak, C., Ilavsky, J., Wang, H., Porter, W., Trice, R.,

“Microstructural Evolution of 7 wt.% Y2O3-ZrO2 Thermal 

Barrier Coatings due to Stress Relaxation at Elevated 

Temperatures and the Concomitant Changes in Thermal 

Conductivity,” Surf. Coat. Technol. in press.

Phelan, D., Millican, J.N., Gehring, P.M., “Dissimilarity of Polar 

Displacements in Barium and Lead Based Relaxors,” Appl. 

Phys. Lett. , in press.

Porcar, L., Falus, P., Chen, W.-R., Faraone, A., Fratini, E., Hong, K.,

Baglioni, P., Liu, Y., “Formation of the Dynamic Clusters in 

Concentrated Lysozyme Protein Solutions,” J. Phys. Chem.

Lett. 1, 126 (2010). [CHRNS]

Porcar, L., Hong, K., Butler, P.D., Herwig, K.W., Smith, G.S.,

Liu, Y., Chen, W.-R., “Intramolecular Structural Change of

PAMAM Dendrimers in Aqueous Solutions Revealed by 

Small Angle Neutron Scattering,” J. Phys. Chem. B 114, 1751 

(2010). [CHRNS]

Posen, I.D., McQueen, T.M., Williams, A.J., West, D.V., Huang, Q.,

Cava, R.J., “Geometric Magnetic Frustration in the R-Type 

Ferrite SrSn2Ga1.3Cr2.7O11 and the Spinel-Based Chromates,” 

Phys. Rev. B 81(13), 134413-1 (2010).

Preston, J.S., Fu, R.S., Pasaogullari, U., Hussey, D.S., Jacobson, 

D.L., “An Updated Look at the Role of Micro-Porous Layer 

on Liquid Water Distribution in Polymer Electrolyte Fuel

Cells,” ECS Trans. 25(1), 311 (2009).

Pynn, R., Fitzsimmons, M.R., Lee, W.T., Stonaha, P., Shah, V.R.,

Washington, A.L., Kirby, B.J., Majkrzak, C.F., Maranville,

B.B., “Birefringent Neutron Prisms for Spin Echo Scattering 

Angle Measurement,” Physica B 404, 2582 (2009).

Qiu, Y., Bao, W., Zhao, Y., Broholm, C., Stanev, V., Tesanovic, Z.,

Gasparovic, Y.C., Chang, S., Hu, J., Qian, B., Fang, M., Mao,

Z., “Spin Gap and Resonance at the Nesting Wave Vector in

Superconducting FeSe0.4Te0.6,” Phys. Rev. Lett. 103(6), 067008-

1 (2009). [CHRNS]

Quan, P., Lai, M.-C., Hussey, D.S., Jacobson, D.L., Kumar, A.,

Hirano, S., “Time-Resolved Water Measurement in a

PEM Fuel Cell Using High-Resolution Neutron Imaging 

Technique,” J. Fuel Cell Sci. Technol., in press.

Raman, K.V., Watson, S.M., Shim, J.H., Borchers, J.A., Chang, J.,

Moodera, J.S., “Effect of Molecular Ordering on Spin and 

Charge Injection in Rubrene,” Phys. Rev. B 80(19), 195212-1 

(2009).

Ramirez-Cuesta, A.J.T., Ryan, K., Brown, C.M., “AB-Initio

Calculations of the Dynamics of Select Hydrogen Storage 

Materials, Compared to Inelastic Neutron Scattering 

Spectra,” in “ACS Division Proceedings, Division of Fuel 

Chemistry,” edited by unknown, (ACS, Fall National 

Meeting & Exposition 2009 Conf. Proc., August 2009, 

Washington, D.C.) 54(2), (2009).

Ratcliff, II, W., Lima Sharma, A.L., Gomes, A.M., Gonzalez, J.L.,

Huang, Q., Singleton, J., “The Magnetic Ground State of

CaMn2Sb2,” J. Magn. Magn. Mater. 321(17), 2612 (2009).

Ratcliff, II W., Kienzle, P.A., Lynn, J.W., Li, S., Dai, P., Chen, G.F.,

Wang, N.L., “Magnetic Form Factor of SrFe2As2: Neutron 

Diffraction Measurements,” Phys. Rev. B 81(14), 140502-1 

(2010).

Ren, S., Laver, M., Wuttig, M., “Nanolamellar Magnetoelectric

BaTiO3-CoFe2O4 Bicrystal,” Appl. Phys. Lett. 95(15), 

153504-1 (2009).

Rexeisen, E.L., Fan, W., Pangburn, T.O., Tarbagil, R.R., Bates,

F.S., Lodge, T.P., Tsapatsis, M., Kokkoli, E., “Self-Assembly 

of Fibronectin Mimetic Peptid-Amphiphile Nanofibers,”

Langmuir 26(3), 1953 (2010).

Rikkou, M.D., Loizou, E., Porcar, L., Butler, P., Patrickios, C.S.,

“Degradable Amphiphilic End-linked Conetworks with 

Aqueous Degradation Rates Determined by Polymer 

Topology,” Macromol. 42, 9412 (2009). [CHRNS]

Rikkou, M.D., Loizou, E., Patrickios, C.S., Porcar, L., “Structural

Characterization of Amphiphilic Polymer Conetworks EndLinked with the Optimal Amount of Cross-Linker,” Eur. 

Polym. J. 46, 441 (2010). [CHRNS]

Rodriguez, E.E., Zavalij, P., Hsieh, P.-Y., Green, M.A., “Iodine as

an Oxidant in the Topotactic Deintercalation of Interstitial 

Iron in Fe1+xTe,” J. Am. Chem. Soc. 132, 10006 (2010).

Roh, J.H., Guo, L., Kilburn, J.D., Briber, R.M., Irving, T., Woodson,

S.A., “Multistage Collapse of a Bacterial Ribozyme Observed

by Time-Resolved Small-Angle X-ray Scattering,” J. Am.

Chem. Soc. 132, 10148 (2010).
76Publications

Ross, K.A., Ruff, J.P.C., Adams, C.P., Gardner, J.S., 

Dabkowska, H.A., Qiu, Y., Copley, J.R.D., Gaulin, B.D.,

“Two-Dimensional Kagome Correlations and Field 

Induced Order in the Ferromagnetic XY Pyrochlore

Yb2Ti2O7,” Phys. Rev. Lett 103(22), 227202-1 (2009). 

[CHRNS]

Rubinson, K.A., Krueger, S., “Poly(ethylene glycol)s 2000-

8000 in Water May be Planar: A Small-Angle Neutron

Scattering (SANS) Structure Study,” Polymer 50(20), 

4852 (2009).

Rule, K.C., Ehlers, G., Gardner, J.S., Qiu, Y., Moskvin,

E., Kiefer, K., Gerischer, S., “Neutron Scattering 

Investigations of the Partially Ordered Pyrochlore 

Tb2Sn2O7,” J. Phys.: Condens. Matter 21, 486005 

(2009). [CHRNS]

Russo, D., Copley, J.R.D., Ollivier, J., Teixeira, J., “On the 

Behaviour of Water Hydrogen Bonds at Biomolecular

Sites: Dependences on Temperature and on Network 

Dimensionality,” J. Mol. Struct. 972, 81 (2010). [CHRNS]

Sahin,I., Yilmazer,N., “A Discrete Fourier Transform

for Alignment of Visual Evoked Potentials,” in 

“Computational Intelligence in Bioinformatics and 

Computational Biology - CIBCB,” edited by unknown, 

(IEEE CIBCB, May 2010, Montreal, Canada) 1 (2010).

Sahoo, P., Adarsh, N.N., Chacko, G.E., Raghavan, S.R., 

Puranik, V.G., Dastidar, P., “Combinatorial Library 

of Primaryalkylammonium Dicarboxylate Gelators: 

A Supramolecular Synthon Approach,” Langmuir 

25(15), 8742 (2009).

Sahoo, P.P., Gaudin, E., Darriet, J., Row, T.N.G., “Synthesis, 

Characterization, and Crystallographic Study in PbOBi2O3-V2O5 System: Pb3-xBi2x/3V2O8 (0.20≤x ≤0.50),”

Inorg. Chem. 49, 5603 (2010).

Sasai, K., Kofu, M., Ibberson, R.M., Hirota, K., Yamaura, 

J.-I., Hiroi, Z., Yamamuro, O., “A Novel Isomorphic

Phase Transition in β-Pyrochlore Oxide KOs2O6: 

A Study using High Resolution Neutron Powder 

Diffraction,” J. Phys.: Condens. Matter 22, 015403 

(2010).

Savici, A.T., Granroth, G.E., Broholm, C.L., Pajerowski, 

D.M., Brown, C.M., Talham, D.R., Meisel, M.W.,

Schmidt, K.P., Uhrig, G.S., Nagler, S.E., “Neutron 

Scattering Evidence for Isolated Spin-1⁄2 Ladders in

(C5D12N)2CuBr4,” Phys. Rev. B 80(9), 094411-1 (2009). 

[CHRNS]

Segawa, K., Kofu, M., Lee, S.-H., Tsukada, I., Hiraka, H., 

Fujita, M., Chang, S., Yamada, K., Ando, Y., “ZeroDoping State and Electron-Hole Asymmetry in an 

Ambipolar Cuprate,” Nat. Phys., in press. [CHRNS]

Shane, D.T., Corey, R.L., McIntosh, C., Rayhel, L.H., 

Bowman, Jr., R.C., Vajo, J.J., Gross, A.F., Conradi, M.S., 

“LiBH4 in Carbon Aerogel Nanoscaffolds: An NMR 

Study of Atomic Motions,” J. Phys. Chem. C 114, 4008 

(2010).

Sharpless, K.E., Lindstrom, R.M., Nelson, B.,C., Phinney, K.W.,

Rimmer, C.A., Sander, L.C., Schantz, M.M., Spatz, R.O.,

Thomas, J.B., Turk, G.C., Wise, S.A., Wood, L.J., Yen, J.H.,

“Preparation and Characterization of Standard Reference

Material 1849Infant/Adult Nutritional Formula,” J. AOAC 

Int. 93(4), 1262 (2010).

Shenoy, S., Moldovan, R., Fitzpatrick, J., Vanderah, D.J., Deserno,

M., Lösche, M., “In-Plane Homogeneity and Lipid Dynamics 

in Tethered Bilayer Lipid Membranes (tBLMs),” Soft Matter, 

in press.

Shibayama, M., Matsunaga, T., Nagao, M., “Evaluation of 

Incoherent Scattering Intensity by Transmission and Sample 

Thickness,” J. Appl. Crystallogr. 42(4), 621 (2009).

Shlyk, L., Ueland, B.G., Lynn, J.W., Huang, Q., De Long, L.E.,

Parkin, S., “Magnetic Structure, Magnetization and

Magnetotransport Properties of (Ba,Sr)Md2±xT4±xO11 (M=Fe,

Co; T=Ru, Ti),” Phys. Rev. B 81(18), 184415-1 (2010).

Shoenfelt, J., Mitkus, R.J., Zeisler, R., Spatz, R.O., Powell, J.,

Fenton, M.J., Squibb, K.A., Medvedev, A.E., “Involvement 

of TLR2 and TLR4 in Inflammatory Immune Responses

Induced by Fine and Coarse Ambient Air Particulate Matter,” 

J. Leukocyte Biol. 86, 303 (2009).

Simmons, J.M., Yildirim, “Thermally Activated Pore Opening in a 

Metal Organic Framework”, in “ACS Division Proceedings, 

Division of Fuel Chemistry,” edited by unknown, (ACS, Fall 

National Meeting & Exposition 2009 Conf. Proc., August 

2009, Washington, D.C.) 54(2), (2009). [CHRNS]

Singh, S., Basu, S., Gupta, M., Majkrzak, C.F., Kienzle, P.A.,

“Growth Kinetics of Intermetallic Alloy Phase at the 

Interfaces of Ni/Al Multilayer using Polarized Neutron and

X-ray Reflectometry,” Phys. Rev. B 81(23), 235413-1 (2010).

Singh, Y., Green, M.A., Huang, Q., Kreyssig, A., McQueeney, R.J.,

Johnston, D.C., Goldman, A.I., “Magnetic Order in BaMn2As2

from Neutron Diffraction Measurements,” Phys. Rev. B 

80(10), 100403-1 (2009).

Siritanon, T., Laurita, G., Macaluso, R.T., Millican, J.N., Sleight, 

A.W., Subramanian, M.A., “First Observation of Electronic

Conductivity in Mixed-Valence Tellurium Oxides,” Chem. 

Mater. 21, 5572 (2009).

Sitepu, H., “Texture and Structural Refinement Using Neutron

Diffraction Data from Molybdite (MoO3) and Calcite (CaCO3) 

Powders and a Ni-Rich Ni50.7Ti49.30 Alloy,” Powder Diffr. 

24(4), 315 (2009).

Smith, M.B., McGillivray, D.J., Genzer, J., Lösche, M., Kilpatrick,

P.K., “Neutron Reflectometry of Supported Hybrid Bilayers

with Inserted Peptide,” Soft Matter 6, 862 (2010).

Spernjak, D., Prasad, A.K., Advani, S.G., “In Situ Comparison of 

Water Content and Dynamics in Parallel, Single-Serpentine,

and Interdigitated Flow Fields of Polymer Electrolyte 

Membrane Fuel Cells,” J. Power Sources 195(11), 3553 (2010).

Stavila, V., Her, J.-H., Zhou, W., Hwang, S.-J., Kim, C., Ottley,

L.A.M., Udovic, T.J., “Probing the Structure, Stability and 

Hydrogen Storage Properties of Calcium DodecahydroCloso-Dodecaborate,” J. Solid State Chem. 183, 1133 (2010).
NCNR 2010 Accomplishments and Opportunities 77

Stock, C., Jonas, S., Broholm, C., Nakatsuji, S., Nambu, Y., 

Onuma, K., Maeno, Y., Chung, J.-H., “Neutron-Scattering 

Measurement of Incommensurate Short-Range Order in 

Single Crystals of the S = 1 Triangular Antiferromagnet

NiGa2S4,” Phys. Rev. Lett. 105(3), 037402-1 (2010). [CHRNS]

Stock, C., Chapon, L.C., Adamopoulos, O., Lappas, A., Giot, M., 

Taylor, J.W., Green, M.A., Brown, C.M., Radaelli, P.G., “OneDimennsional Magnetic Fluctuations in the Spin-2Triangular 

Lattice α-NaMnO2,” Phys. Rev. Lett. 103(7), 077202-1 (2009). 

[CHRNS]

Stock, C., Van Eijck, L., Fouquet, P., Maccarini, M., Gehring, P.M., 

Xu, G., Luo, H., Zhao, X., Li, J., Viehland, D., “Interplay

Between Static and Dynamic Polar Correlations in Relaxor 

Pb(Mg1/3Nb2/3)O3,” Phys. Rev. B 81(14), 144127-1 (2010). 

[CHRNS]

Stoltz, C.A., Mason, B.P., Hooper, J., “Neutron Scattering Study

of Internal Void Structure in RDX,” J. Appl. Phys. 107(10), 

103527-1 (2010). [CHRNS]

Sumida, K., Horike, S., Kaye, S.S., Herm, Z.R., Queen, W.L.,

Brown, C.M., Grandjean, F., Long, G.J., Dailly, A., Long, J.R., 

“Hydrogen Storage and Carbon Dioxide Capture in an IronBased Sodalite-Type Metal-Organic Framework (Fe-BTT) 

Discovered via High-Throughput Methods,” Chem. Sci., in 

press.

Sun, D., Ma, S., Simmons, J.M., Li, J.-R., Yuan, D., Zhou, H.-C.,

“An Unusual Case of Symmetry-Preserving Isomerism,” 

Chem. Commun. 46, 1329 (2010).

Sun, K., Raghavan, S.R., “Thermogelling Aqueous Fluids 

Containing Low Concentrations of Pluronic F127 and 

Laponite Nanoparticles,” Langmuir 26(11), 8015 (2010).

Taribagil, R.R., Hillmyer, M.A., Lodge, T.P., “Hydrogels from ABA 

and ABC Triblock Polymers,” Macromol. 43, 5396 (2010). 

[CHRNS]

Thomas, J.J., Allen, A.J., Jennings, H.M., “Hydration Kinetics 

and Microstructure Development of Normal and CaCl2-

Accelerated Tricalcium Silicate Pastes,” J. Phys. Chem. C 113, 

19836 (2009).

Thomas, J.J., Jennings, H.M., Allen, A.J., “Relationships between 

Composition and Density of Tobermorite, Jennite, and 

Nanoscale CaO-SiO2-H20,” J. Phys. Chem. C 114, 7594 (2010). 

[CHRNS]

Thompson, A.J., Sharp, J.W., Rawn, C.J., “Microstructure and

Crystal Structure in TAGS Compositions,” J. Electron. Mater. 

38(7), 1407 (2009).

Thompson, S.M., Ma, H.B., “Effect of Localized Heating on ThreeDimensional Flat-Plate Oscillating Heat Pipe,” Adv. Mech. 

Eng. 2010 Article ID 465153, 1 (2010).

Todd, A.D.W., Ferguson, P.P., Barker, J.G., Fleischauer, M.D.,

Dahn, J.R., “Comparison of Mechanically Milled and Sputter 

Deposited Tin-Cobalt-Carbon Alloys using Small Angle 

Neutron Scattering,” J. Electrochem. Soc. 156(12), A1034 

(2009).

Tominaga, T., Osada, Y., Gong, J.P., “Structural Approaches 

on the Toughness in Double Network Hydrogels,” in 

“Chemomechanical Instabilities in Responsive Materials,” 

edited by Borckman, P., De Kepper, P., Kholehlov, R., and 

Métens, S., (NATO Science for Peace and Security Series A: 

Chemistry and Biology), 117 (2009). [CHRNS]

Tomlin, B.E., Zeisler, R., “Improvements in Determinations Using

the Cu-64 Annihilation Gamma Rays,” Appl. Radiat. Isot. 

67(12), 2075 (2009).

Tristram-Nagle, S., Kim, D.J., Akhunzada, N., Kŭcerka, N.,

Mathai, J.C., Katsaras, J., Zeidel, M., Nagle, J.F., “Structure

and Water Permeability of Fully Hydrated DiphytanoylPC,”

Chem. Phys. Lipids 163, 630 (2010). [CHRNS]

Tsao, C.-S., Liu, Y., Li, M., Zhang, Y., Leao, J.B., Chang, H.-W., Yu,

M.-S., Chen, S.-H., “Neutron Scattering Methodology for 

Absolute Measurement of Room-Temperature Hydrogen 

Storage Capacity and Evidence for Spillover Effect in a 

Pt-Doped Activated Carbon,” J. Phys. Chem. Lett. 1(10), 

1569 (2010).

Tu, R.S., Marullo, R., Pynn, R., Bitton, R., Bianco-Peled, H., Tirrell, 

M.V., “Cooperative DNA Binding and Assembly by a bZip

Peptide-Amphiphile,” Soft Matter 6, 1035 (2010).

Ueland, B.G., Gardner, J.S., Williams, A.J., Dahlberg, M.L.,

Kim, J.G., Qiu, Y., Copley, J.R.D., Schiffer, P., Cava,

R.J., “Coexisting Magnetic Order and Cooperative 

Paramagnetism in the Stuffed Pyrochlore Tb2+xTi2-2xNbxO7,” 

Phys. Rev. 81(6), 060408-1 (2010). [CHRNS]

Ueland, B.G., Lynn, J.W., Laver, M., Choi, Y.J., Cheong, S.-

W., “Origin of Electric-Field-Induced Magnetization in

Multiferroic HoMnO3,” Phys. Rev. Lett. 104(14), 147204-1 

(2010). [CHRNS]

van der Zaag, P. J., Borchers, J.A., “AntiferromagneticFerromagnetic Oxide Multilayers: Fe3O4-Based Systems as a 

Model,” in “Magnetic Properties of Antiferromagnetic Oxide 

Materials,”edited by Duò, L., Finazzi, M., and Ciccacci, F,

(Wiley-VCH Verlag GMBH & Co. KGaA, Weihheim) Chap. 7,

239 (2010).

Verdal, N., Hartman, M.R., Jenkins, T., DeVries, D.J., Rush, J.J., 

Udovic, T.J., “Reorientational Dynamics of NaBH4 and 

KBH4,” J. Phys. Chem. C 114, 10027 (2010). [CHRNS]

Verdal, N., Hartman, M.R., Bacon, M., Jenkins, T.A., Rush, 

J.J., Udovic, T.J, “Hydorgen Dynamics of Alkali-Metal 

Borohydrides,” in “ACS Division Proceedings, Division of 

Fuel Chemistry,” edited by unknown, (ACS, Fall National 

Meeting & Exposition 2009 Conf. Proc., August 2009, 

Washington, D.C.) 54(2), (2009). [CHRNS]

Virgili, J.M., Nedoma, A.J., Segalman, R.A., Balsara, N.P., “Ionic 

Liquid Distribution in Ordered Block Copolymer Solutions,” 

Macromol. 43, 3750 (2010).

Wang, B., Tchessalov, S., Cicerone, M.T., Warne, N.W., Pikal, M.J.,

“Impact of Sucrose Level on Storage Stability of Proteins in 

Freeze-Dried Solids: II. Correlation of Aggregation Rate with

Protein Structure and Molecular Mobility,” J. Pharm. Sci. 

98(9), 3145 (2009). [CHRNS]
78Publications

Wang, B., Cicerone, M.T., Aso, Y., Pikal, M.J., “The Impact

of Thermal Treatment on the Stability of Freeze-Dried

Amorphous Pharmaceuticals: II. Aggregation in an 

IgG1Fusion Protein,” J. Pharm. Sci. 99(2), 683 (2010).

Wang, B., Pikal, M.J., “The Impact of Thermal Treatment

on the Stability of Freeze Dried Amorphous

Pharmaceuticals: I. Dimer Formation in Sodium 

Ethacrynate,” J. Pharm. Sci. 99(2), 663 (2010).

Wang, C.-W., Wu, C.-M., Li, C.-Y., Karna, S.K., Hsu, C.-K.,

Li, C.H.C., Li, W.-H., Yu, C.-C., Wu, C.-P., Chou,

H., Lynn, J.W., “Short Range Magnetic Correlations

Induced by La Substitution in Ho1-xLaxMn2O5,” J. 

Phys.: Condens. Matter 22, 246002 (2010).

Wang, H., “Dispersing Carbon Nanotubes Using

Surfactants,” Curr. Opin. Colloid Interface Sci. 14, 364 

(2009). [CHRNS]

Wang, M., Luo, H., Zhao, J., Zhang, C., Wang, M., Marty,

K., Chi, S., Lynn, J.W., Schneidewind, A., Li, S., Dai,

P., “Electron-Doping Evolution of the Low-Energy 

Spin Excitations in the Iron Arsenide Superconductor 

BaFe2-xNixAs2,” Phys. Rev. B 81(17), 174524-1 (2010).

Wang, X., Yakovlev, S., Beers, K.M., Park, M.J., Mullin,

S.A., Downing, K.H., Balsara, N.P., “On the Origin of 

Slow Changes in Ionic Conductivity of Model Block 

Copolymer Electrolyte Membranes in Contact with 

Humid Air,” Macromol. 43, 5306 (2010). [CHRNS]

Wang, Y., Mukherjee, P.P., Mishler, J., Mukundan, R., Borup,

R.L., “Cold Start of Polymer Electrolyte Fuel Cells: 

Three-Stage Startup Characterization,” Electrochim.

Acta 55, 2636 (2010).

Weck, P.F., Kim, E., Poineau, F., Rodriguez, E.E.,

Sattelberger, A.P., Czerwinski, K.R., “Structural

and Electronic Trends in Rare-Earth Technetate 

Pyrochlores,” Dalton Trans., in press.

Weigandt, K. M., Pozzo, D.C., Porcar, L., “Structure of

High Density Fibrin Networks Probed with Neutron 

Scattering and Rheology,” Soft Matter 51(21), 4321 

(2009). [CHRNS]

Wen, J., Xu, G., Xu, Z., Lin, Z.W., Li, Q., Chen, Y., Chi, S.,

Gu, G., Tranquada, J.M., “Effect of Magnetic Field on 

the Spin Resonance in FeTe0.5Se0.5 as seen via Inelastic 

Neutron Scattering,” Phys. Rev. B 81(10), 100513-1 

(2010).

Wen, J., Xu, G., Gu, G., Shapiro, S.M., “Robust Charge and

Magnetic Orders under Electric Field and Current 

Multiferroic LuFe2O4,” Phys. Rev. B 81(14), 144121-1 

(2010).

Wen, J., Xu, G., Xu, Z., Lin, Z.W., Li, Q., Ratcliff, W., Gu,

G., Tranquada, J.M., “Short-Range Incommensurate 

Magnetic Order Near the Superconducting Phase 

Boundary in Fe1+δTe1-xSex,” Phys. Rev. B 80(10), 

104506-1 (2009).

West, D.V., Posen, I.D., Huang, Q., Zandbergen, H.W.,

McQueen, T.M., Cava, R.J., “PbMn(SO4)2: A New Chiral 

Antiferromagnet,” J. Solid State Chem. 182(9), 2461 (2009).

Whitney, S.M., Biegalski, S.R.F., Downing, G., “Benchmarking and

Analysis of 6Li Neutron Depth Profiling of Lithium Ion Cell

Electrodes,” J. Radioanal. Nucl. Chem. 282, 173 (2009).

Wietfeldt, F.E., Byrne, J., Collett, B., Dewey, M.S., Jones, G.L.,

Komives, A., Laptev, A., Nico, J.S., Noid, G., Stephenson, 

E.J., Stern, I., Trull, C., Yerozolimsky, B.G., “aCORN:

An Experiment to Measure the Electron-Antineutrino 

Correlation in Neutron Decay,” Nucl. Instrum. Meth. A 611, 

207 (2009).

Williams, R.E., Richards, W.J., O’Kelly, S., Rowe, J.M., Diamond,

D.J., Hanson, A.L., Cheng, L.-Y., Cuadra, A., “LEU 

Conversion of the NIST Research Reactor: Maintaining Core 

Geometry to Avoid a Startup Core,” in “Proceedings of the 

Conference on the Physics of Reactors,” (PHYSOR, Pittsburg, 

PA, May 2010) CD-ROM (2010).

Wu, H., Zhou, W., Pinkerton, F.E., Meyer, M.S., Srinivas, G.,

Yildirim, T., Udovic, T.J., Rush, J.J., “A New Family of Metal 

Borohydride Ammonia Borane Complexes: Synthesis, 

Structures, and Hydrogen Storage Properties,” J. Mater. 

Chem., in press.

Wu, H., Simmons, J.M., Liu, Y, Brown, C.M., Wang, X.-S., Ma,

S., Peterson, V.K., Southon, P.D., Kepert, C.J., Zhou, H.-C.,

Yildirim, T., Zhou, W., “Metal-Organic Frameworks with

Exceptionally High Methane Uptake: Where and How is

Methane Stored?,” Chem. Eur. J. 16, 5205 (2010).

Wu, H., Skripov, A.V., Udovic, T.J., Rush, J.J., Derakhshan,

S., Kleinke, H., “Hydrogen in Ti3Sb and Ti2Sb: Neutron 

Vibrational Spectroscopy and Neutron Diffraction Studies,” 

J. Alloys Compd. 496, 1 (2010). [CHRNS]

Wu, H., Zhou, W., Udovic, T.J., Rush, J.J., Yildirim, T., “Crystal

Chemistry and Dehydrogenation/Rehydrogenation 

Properties of Perovskite Hydrides RbMgH3 and RbCaH3,” 

J. Phys. Chem. C 113(33), 15091 (2009).

Wu, H., Simmons, J.M., Srinivas, G., Zhou, W., Yildirim, T.,

“Adsorption Sites and Binding Nature of CO2 in Prototypical 

Metal-Organic Frameworks: A Combined Neutron 

Diffraction and First-Principles Study,” J. Phys. Chem. Lett. 

1(13), 1946 (2010).

Wu, Y., Yu, B., Jackson, A., Zha, W., Lee, L.J., Wyslouzil, B.E.,

“Coaxial Electrohydrodynamic Spraying: A Novel One-Step 

Technique to Prepare Oligodeoxynucleotide Encapsulated 

Lipoplex Nanoparticles,” Mol. Pharm. 6(5), 1371 (2009).

Xiang, S., Zhou, W., Gallegos, J.M., Liu, Y., Chen, B.,

“Exceptionally High Acetylene Uptake in a Micro-porous 

Metal-Organic Framework with Open Metal Sites,” J. Am. 

Chem. Soc. 131(34), 12415 (2009).

Xiang, S., Zhou, W., Zhang, Z., Green, M.A., Liu, Y., Chen, B.,

“Open Metal Sites within Isostructural Metal-Organic 

Frameworks for Differential Recognition of Acetylene and 

Extraordinarily High Acetylene Storage Capacity at Room 

Temperature,” Angew. Chem. Int. Edit. 49(27), 4615 (2010).
NCNR 2010 Accomplishments and Opportunities 79

Xie, W., He, J., Kang, H.J., Tang, X., Zhu, S., Laver, M., Wang,

S., Copley, J.R.D., Brown, C.M., Zhang, Q., Tritt, T.M.,

“Identifying the Specific Nanostructures Responsible

for the High Thermoelectric Performance of (Bi,Sb)2Te3

Nanocomposites,” Nano Letters , in press. [CHRNS]

Yamada, N.L., Endo, H., Osaka, N., Kawabata, Y., Nagao, M., 

Takeda, T., Seto, H., Shibayama, M., “Dector Area Expansion 

at iNSE Neutron Spin Echo Spectrometer,” Physica B 404(17), 

2607 (2009).

Yang, C.-C., Li, W.-H., Wu, C.-M., Li, C.H.C., Sun, J., Lynn, J.W.,

“Interplay Between the Crystalline and Magnetic Structures 

in Lightly Cr-Doped Bi0.37Ca0.63Mn0.96Cr0.04O2.99,” Inorg. 

Chem. 49, 3297 (2010).

Yang, H., Shin, K., Tae, G., Satija, S.K., “Structure of a Monolayer 

of Poly(Ethylene Glycol) End-Capped with a Fluoroalkyl 

Group and its Relationship with Protein Adsorption at the 

Aqueous Interface,” Soft Matter 5(14), 2731 (2009).

Yang, K.X., Kitto, M.E., Orsini, J.P., Swami, K., Beach, S.E.,

“Evaluation of Sample Pretreatment Methods for 

Multiwalled and Single-walled Carbon Nanotubes for the 

Determination of Metal Impurities by ICPMS, ICPOES, 

and Instrument Neutron Activation Analysis,” J. Anal. At. 

Spectrom., in press.

Yao, J., Wang, Z., van Tol, J., Dalal, N.S., Aitken, J.A., “Site

Preference of Manganese on the Copper Site in MnSubstituted CuInSe2 Chalcopyrites Revealed by a Combined 

Neutron and X-ray Powder Diffraction Study,” Chem. Mater.

22(5), 1647 (2010).

Ye, F., Chi, S., Fernandez-Baca, J.A., Moreo, A., Dagotto, E.,

Lynn, J.W., Mathieu, R., Kaneko, Y., Tokura, Y., Dai, P.,

“Electronic Self-Organization in the Single-Layer Manganite

Pr1-xCa1+xMnO4,” Phys. Rev. Lett. 103(16), 167202-1 (2009).

Yoonessi, M., Dang, T.D., Heinz, H., Wheeler, R., Bai, Z.,

“Investigation of Nanostructures and Properties of 

Sulfonated Poly(arylenethioethersulfone) Copolymer as 

Proton Conducting Materials by Small Angle neutron 

Scattering,” Polymer 51, 1585 (2010).

Yu, J., Louca, D., Phelan, D., Tomiyasu, K., Horigane, K., Yamada, 

K., “Uncharacteristic Phase Separation Trends with the 

Ionic Size in Cobaltites,” Phys. Rev. B 80(5), 052402-1 (2009). 

[CHRNS]

Yuan, G., Li, C., Satija, S.K., Karim, A., Douglas, J.F., Han, C.C., 

“Observation of a Characteristic Length Scale in the Healing 

of Glassy Polymer Interfaces,” Soft Matter , in press.

Yue, M., Li, Z.Q., Xu, H., Huang, Q.Z., Liu, X.B., Liu, D.M., Zhang,

J.X., “Effect of Annealing on the Structure and Magnetic

Properties of Mn1.1Fe0.9P0.8Ge0.2 Compound,” J. Appl. Phys. 

107(9), 09A939-1 (2010).

Zeisler, R., Ünlü, K., Heller-Zeisler, S.F., Williamson, R.C.,

“Current Status, Trends, and Needs in Radiochemical 

Education: the US and Abroad Panel Summary and 

Discussion,” in “8th International Conference on Methods 

and Applications of Radioanalytical Chemistry: MARC-VII,” 

edited by Ünlü, K., Heller-Zeisler, S., and Zeisler, R.,

(AIP Conf. Proc., April 2009 Kona, HI,) 1164, 3 (2009).

Zeisler, R., Tomlin, B.E., Murphy, K.E., Kŭcera, J., “Neutron

Activation Analysis with Pre- and Post- Irradiation Chemical 

Separation for the Value Assignments of Al, V, and Ni in the 

New Bovine Liver SRM 1577C,” J. Radioanal. Nucl. Chem. 

282(1), 69 (2009).

Zenobia, S.J., Kulcinski, G.L., “Formation and Retention of Surface

Pores in Helium-Implanted Nano-Grain Tungsten for Fusion 

Reactor First-Wall Materials and Divertor Plates,” Phys. Scr.

T138, 014049 (2009).

Zhang, F., Ilavsky, J., Long, G.G., Quintana, J.P.G., Allen, A.J.,

Jemian, P.R., “Glassy Carbon as an Absolute Intensity 

Calibration Standard for Small-Angle Scattering,” Metall. 

Mater. Trans. A 41A, 1151 (2010).

Zhang, X., Yager, K.G., Kang, S., Fredin, N.J., Akgun, B., Satija,

S., Douglas, J.F., Karim, A., Jones, R.L., “Solvent Retention 

in Thin Spin-Coated Polystyrene and Poly(methyl 

methacrylate) Homopolymer Films Studied by Neutron 

Reflectometry,” Macromol. 43, 1117 (2010).

Zhao, L., Robinson, L., “A Comparison Between Cold and

Thermal Neutron Prompt Gamma Activation Analysis in 

the Determination of Carbon, Nitrogen, and Phosphorus in 

Cattail,” J. Radioanal. Nucl. Chem. 282(1), 151 (2009).

Zhou, H.D., Wiebe, C.R., Janik, J.A., Vogt, B., Harter, A., Dalal,

N.S., Gardner, J.S., “Spin Glass Transitions in the Absence 

of Chemical Disorder for the Pyrochlores A2Sb2O7 (A=Mn,

Co, Ni),” J. Solid State Chem. 183, 890 (2010).

Zhou, S., Zhang, J., Liu, D., Lin, Z., Huang, Q., Bao, L., Ma, R.,

Wei, Y., “Synthesis and Properties of Nanostructured Dense

LaB6 Cathodes by Arc Plasma and Reactive Spark Plasma 

Sintering,” Acta Mater., in press.

Zhou, W., “Role of Open Metal Sites on H2 and CH4 Adsorption in 

Metal-Organic Frameworks,” in “ACS Division Proceedings, 

Division of Fuel Chemistry,” edited by unknown, (ACS, Fall 

National Meeting & Exposition 2009 Conf. Proc., August 

2009, Washington, D.C.) 54(2), (2009).

Zhou, W., “Methane Storage in Porous Metal-Organic

Frameworks: Current Records and Future Perspectives,” 

Chem. Rec. 10, 200 (2010).

Zsolt, R., Lindstrom, R.M., Mackey, E.A., Belgya, T., “NeutronInduced Prompt Gamma Activation Analysis (PGAA)”, 

in “Handbook of Nuclear Chemistry (2nd ed)”edited by: 

Klencsár, Z., Lovas, R.G., Sándor, N., Rösch, S., and Vértes,

A., (Springer), in press.
80Instruments and Contacts

Instruments and Contacts

Instruments and Contacts: (name, tel. 301-975-xxxx, 

email)

High Resolution Powder Diffractometer (BT-1):

• Judy Stalick, 6223, judith.stalick@nist.gov

•	 Qingzhen Huang, 6164, qing.huang@nist.gov

•	 Mark Green, 4297, mark.green@nist.gov

•	 Sarah Parks, 8489, sarahp@nist.gov

Residual Stress Diffractometer (BT-8):

•	 Thomas Gnaeupel-Herold, 5380, tg-h@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

USANS, Perfect Crystal SANS (BT-5) (CHRNS):

•	 Andrew Jackson, 3146, andrew.jackson@nist.gov

•	 David Mildner, 6366, david.mildner@nist.gov

•	 Paul Butler, 2028, paul.butler@nist.gov

Reflectometer, Vertical Sample, Polarized Beam Option 

(NG-1):

•	 Brian Kirby, 8395, brian.kirby@nist.gov

•	 Julie Borchers, 6597, julie.borchers@nist.gov

•	 Chuck Majkrzak, 5251, cmajkrzak@nist.gov

AND/R, Advanced Neutron Diffractometer/Reflectometer 

(NG-1):

•	 Joe Dura, 6251, joseph.dura@nist.gov

•	 Brian Maranville, 6034, brian.maranville@nist.gov

Reflectometer, Horizontal Sample (NG-7):

•	 Sushil Satija, 5250, satija@nist.gov

•	 Bulent Akgun, 6469, bulent.akgun@nist.gov

Double-focusing Triple Axis Spectrometer (BT-7)

•	 Sung Chang, 8369, sung.chang@nist.gov

•	 Yang Zhao, 2164, yang.zhao@nist.gov

•	 Jeff Lynn, 6246, jeff.lynn@nist.gov

Triple-axis Spectrometer (BT-9):

•	 William Ratcliff, 4316, william.ratcliff@nist.gov

•	 Ross Erwin, 6245, rerwin@nist.gov 

•	 Jeff Lynn, 6246, jeff.lynn@nist.gov

SPINS, Spin-polarized Triple-axis Spectrometer (NG-5) 

(CHRNS):

•	 Peter Gehring, 3946, peter@nist.gov

•	 Deepak Singh, 4863, deepak.singh@nist.gov

MACS, Multi-Analyzer Crystal Spectrometer (NG-0)

•	 Jose Rodriguez, 6019, jose.rodriguez@nist.gov

•	 Chris Stock, 6422, chris.stock@nist.gov

FANS, Filter-analyzer Neutron Spectrometer (BT-4)

•	 Terry Udovic, 6241, udovic@nist.gov

•	 Juscelino Leão, 8867, juscelino.leao@nist.gov

DCS, Disk-chopper Time-of-flight Spectrometer (NG-4) (CHRNS):

•	 John Copley, 5133, jcopley@nist.gov

•	 Yiming Qiu., 3274, yiming.qiu@nist.gov

•	 Craig Brown, 5134, craig.brown@nist.gov

HFBS, High-flux Backscattering Spectrometer (NG-2) (CHRNS):

•	 Madhusudan Tyagi, 2046, mtyagi@nist.gov

•	 Tim Jenkins, 8396, timothy.jenkins@nist.gov

NSE, Neutron Spin Echo Spectrometer (NG-5) (CHRNS):

•	 Antonio Faraone, 5254, antonio.faraone@nist.gov

•	 Jason Gardner, 8396, jason.gardner@nist.gov

•	 Michi Nagao, 5505, michihiro.nagao@nist.gov

Cold Prompt-gamma Neutron Activation Analysis (NG-7): 

•	 Rick Paul, 6287, rpaul@nist.gov

Thermal Prompt-gamma Neutron Activation Analysis (VT-5): 

•	 Rick Paul, 6287, rpaul@nist.gov

Other Activation Analysis Facilities: 

•	 Greg Downing, 3782, gregory.downing@nist.gov

Cold Neutron Depth Profiling (NG-1):

•	 Greg Downing, 3782, gregory.downing@nist.gov

Neutron Imaging Station (BT-2):

•	 David Jacobson, 6207, david.jacobson@nist.gov

•	 Dan Hussey, 6465, daniel.hussey@nist.gov

•	 Muhammad Arif, 6303, muhammad.arif@nist.gov

Neutron Interferometer (NG-7):

•	 Muhammad Arif, 6303, muhammad.arif@nist.gov

•	 David Jacobson, 6207, david.jacobson@nist.gov

•	 Dan Hussey, 6465, daniel.hussey@nist.gov

Fundamental Neutron Physics Station (NG-6): 

•	 NG-6M: Scott Dewey, 4843, mdewey@nist.gov

•	 NG-6U: Pieter Mumm, 8355, pieter.mumm@nist.gov

•	 NG-6: Jeff Nico, 4663, nico@nist.gov

Theory and Modeling:

•	 Joseph Curtis, 3959, joseph.curtis@nist.gov

•	 Taner Yildirim, 6228, taner@nist.gov

Sample Environment: 

•	 Toby Herman, 5010, tobias.herman@nist.gov

•	 Julia Scherschligt, 5328, julia.scherschligt@nist.gov

•	 Juscelino Leão, 8867, juscelino.leao@nist.gov

User Laboratories:

•	 Kim Tomasi, 4533, kimberly.tomasi@nist.gov

•	 Yamali Hernandez, 5295, yamali@nist.gov
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

Nationial Institute of Standards and Technology

100 Bureau Drive, Mail Stop 6100

Gaithersburg, MD 20899-6100

USA
NIST CENTER FOR NEUTRON RESEARCH

National Institute of Standards and Technology

100 Bureau Drive, MS 6100

Gaithersburg, MD 20899-6100

www.ncnr.nist.gov