NIST CENTER FOR NEUTRON RESEARCH

2014 Accomplishments and Opportunities

NIST SP 1177
ON THE COVER

Conversion of light 

alkanes into value-added 

chemicals remains an 

outstanding scientific 

challenge. The oxidation 

of ethane to ethanol on 

an iron(II) metal-organic 

framework is described 

in the highlight article by 

Hudson et al. on p.18.
NIST Special Publication 1177

Robert M. Dimeo, Director

Steven R. Kline, Editor

December 2014

U.S. Department of Commerce

Penny Pritzker, Secretary

National Institute of Standards and Technology 

Willie May, Acting Under Secretary of Commerce for 

Standards and Technology and Acting Director 

2014 NIST Center for Neutron Research

Accomplishments and Opportunities
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. Error bars in figures represent 

one standard deviation unless otherwise stated.

National Institute of Standards and Technology

Special Publication 1177 

Natl. Inst. Stand. Technol. Spec. Publ. 1177, 88 pages 

(December 2014) 

CODEN: NSPUE2

This publication is available free of charge from: 

http://dx.doi.org/10.6028/NIST.SP.1177
Table of Contents

FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  ii

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

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

NCNR IMAGES 2014 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  

HIGHLIGHTS

BIOLOGY

Revealing protein complexes at the lipid membrane, J. C. Lee et al.,.

A sticky situation: antibody adsorption, desorption and aggregation at solid-liquid interfaces, H. Nanda et al., (nSoft).

Determination of monoclonal antibody conformation using SANS and refined using free energy constraints, 

N. J. Clark et al., (CHRNS). .

CHEMICAL PHYSICS

Tunable CO/H2 and CO/N2 separations in metal-organic frameworks with exposed divalent metal cations 

via reversible CO binding, M. R. Hudson et al.,. .

Crystal and magnetic stripes coupled to cooperative Jahn-Teller effects in Na5/8MnO2, X. Li et al.,. .

Anion reorientations, sodium mobility, and superionic conduction in Na2B12H12, N. Verdal et al., (CHRNS). .

Oxidation of ethane to ethanol by N2O in an iron(II) metal-organic framework, M. R. Hudson et al.,. .

Dynamic origin of the anomalous odd-even glass transition temperature in an ionic glass, K. Yang et al., (CHRNS). 

CONDENSED MATTER

TiAu: the first itinerant antiferromagnet with no magnetic elements, E. Svanidze et al.,. 

The fluctuating magnetism of triangular molecules on a triangular lattice, M. Mourigal et al., (CHRNS). . . . . . . . . . . . . . . . . 24

Giant charge fluctuations with Se-height and Fe-vacancy formation in MxFe2−ySe2, X. Luo et al.,. .

Phonon localization drives polar nanoregions in a relaxor ferroelectric, M. E. Manley et al.,. 

Effect of interfacial octahedral behavior in ultrathin manganite films, E. J. Moon et al.,. 

ENGINEERING PHYSICS

Comparison of methods for the measurement of deformation induced martensite formation, K. S. Raghavan et al.,. .

NEUTRON PHYSICS

Determining the effective transverse coherence of a neutron wave packet, C. F. Majkrzak et al.,. 

Improved determination of the neutron lifetime, A. T. Yue et al.,. 

2014 ACCOMPLISHMENTS AND OPPORTUNITIES i
SOFT MATTER

Shaken or stirred? It matters when addressing the dynamics and stability of macromolecular 

nanocarriers in aqueous solution, T. H. Epps, III et al.,. 

Universal scaling of polymer diffusion in nanocomposites, J. Choi et al., (CHRNS). 

Probing the relationship between water content and chain dynamics in fuel cell membranes,

K. A. Page et al., (nSoft) (CHRNS). 

Observation of spatially dependent heterogeneity of constrained local motions of rubber in carbon 

black nanocomposites, J. H. Roh et al., (CHRNS). 

ADVANCES IN MEASUREMENT

Development of a neutron microscope, D. S. Hussey et al.,. 

A scaling law to describe the average local structure of biomolecules, M. Watson et al.,. .

Comparison of INAA and LC-ICP-MS for the determination of As species in marine tissues, R. Zeisler et al.,. 

Wide-angle polarization analysis with neutron spin filters, T. R. Gentile et al.,. 

Advances in measuring time-resolved neutron scattering from flowing complex fluids, S. A. Rogers et al.,. 

Development of a scintillator-based proportional counter for use in a chromatically analyzing neutron detector, 

N. C. Maliszewskyj et al.,. .

SLDMOL: A tool for the structural characterization of thermally disordered membrane proteins, H. Nanda et al.,. 

NEUTRON SOURCE OPERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  5

FACILITY DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  5

SERVING THE SCIENCE AND TECHNOLOGY COMMUNITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

NEUTRON WORKSHOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  5

THE CENTER FOR HIGH RESOLUTION NEUTRON SCATTERING (CHRNS) . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

2014 AWARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6

PUBLICATIONS: AUGUST 1, 2013 TO JULY 31, 2014 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6

INSTRUMENTS AND CONTACTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

NIST CENTER FOR NEUTRON RESEARCH CONTACTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  inside back cove

ii NIST CENTER FOR NEUTRON RESEARCH
Foreword

I

am delighted to present this year’s Accomplishments and 

Opportunities for the NIST Center for Neutron Research. 

The reactor was scheduled to operate for 235 days during 

the reporting period (factoring in the loss of days due to the 

government shutdown in October) and did operate for 218 days 

yielding 93 % operations reliability. Both cold sources operated 

with greater than 99 % reliability, i.e. the cold sources held 

the reactor from operating for one day during the year. There 

were many noteworthy facility developments this year. In 

order to ensure robust, long-term source operations, NCNR 

continued to pursue an active reactor lifetime extension 

program. Details of this past year’s progress can be found 

in the pages of this report. Users returned to the Neutron 

Spin-Echo instrument following its relocation to a dedicated 

neutron guide in the guide hall extension. The move included 

installation of a new polarizer and new power supplies resulting 

in higher performance and improved instrument availability and 

reliability. One of the 30m SANS instruments was relocated to 

an endstation in the guide hall extension where the beam is 

tailored for SANS instrumentation, resulting in a performance 

improvement. Design and procurements continued on the 

VSANS and CANDoR instruments as well as planning for the 

installation of the Cold Neutron Imaging station on NG-6. 

In addition, the first wide-angle polarized beam measurements 

were carried out on MACS. This is a significant development in 

our polarized beam program, marking yet another important 

capability that NCNR makes available to its users. Finally, design 

work commenced for a significant upgrade of the engineering 

diffractometer as part of a targeted NIST initiative on Advanced 

Neutron Technologies.

After VSANS, CANDoR, and the Cold Neutron Imaging 

instruments are commissioned (≈2018), we will have completed 

the major neutron instruments and user capabilities that the 

scientific community requested in the NCNR Expansion 

Workshop held in 2006. In order to plan for the next 5 to 

10 years, we held a workshop on August 21-22 in Potomac, 

MD, titled “Neutron Measurements for Materials Design & 

Characterization.” This two-day event featured speakers who 

described many exciting opportunities in science driving the 

needs for new, innovative neutron scattering instruments and 

sample environment. As of this writing we are awaiting the 

final report from the topical break-out groups but it was clear 

from the close-out presentations at the workshop that there 

is no shortage of new, great ideas. Stay tuned for more details 

as the results of this workshop will shape the future of NCNR 

developments.

Amidst these many developments and planning for the future, 

the scientific community produced a wealth of first-class 

research using the NCNR instruments. In this report you will 

find a collection of short highlights of some of that research. 

I think that you will find that they exemplify the high quality 

of work that the community is carrying out here at the NCNR 

throughout the year.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES iiiFOREWORD
The guide hall extension as seen in April 2014, was quickly becoming populated with new and relocated instruments. The new 10m Small Angle 

Neutron Scattering (SANS) instrument was operational in January 2013 and is the primary neutron instrument for the nSOFT consortium. The 

move of the 30m SANS from NG3 to NGB started in March 2014, and the instrument returned to full operation in May 2014. The Neutron Spin 

Echo instrument (NSE) formerly at NG5 was relocated starting in fall 2013, and after upgrading many components, returned to operation in 

August 2014. In addition, the MAGIK and PBR reflectometers are located on the new guides and have been operational since 2012.

iv NIST CENTER FOR NEUTRON RESEARCH
The NIST Center for Neutron Research

Neutrons provide a uniquely effective probe of the structure 

and dynamics of materials ranging from water moving near 

the surface of proteins to magnetic domains in memory 

storage materials. The properties of neutrons (outlined at right) 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 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 two large area liquid hydrogen moderators, 

or cold sources, that provide long wavelength guided neutron beams 

for industrial, government, and academic researchers.

There are currently 28 experiment stations: 12 provide high neutron 

flux positions for neutron physics, analytical chemistry, or imaging, 

and 16 are beam facilities 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/. 

The second guide hall is currently populated with seven instruments. 

Three new cold neutron instruments are under development, including 

a very small angle neutron scattering instrument, a quasi-white beam 

neutron reflectometer and a cold neutron imaging station.

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, about 

2000 research participants from government, industry, and academia 

from all areas of the country are served by the facility (see pp. 56). 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 currently operates six of 

the world’s most advanced instruments (see pp. 61). Time on CHRNS 

instruments is made available through the proposal system. Some 

access to beam time for collaborative measurements with the NIST 

science staff can also be arranged on other instruments.

Why Neutrons?

Neutrons reveal properties not readily probed by photons or 

electrons. They are electrically neutral and therefore easily 

penetrate ordinary matter. They behave like microscopic 

magnets, propagate as waves, can set particles into motion, 

losing or gaining energy and momentum in the process, and 

they can be absorbed with subsequent emission of radiation 

to uniquely fingerprint chemical elements.

WAVELENGTHS − in practice range from ≈ 0.01 nm 

(thermal) to ≈ 1.5 nm (cold) (1 nm = 10 Å), allowing the 

formation of observable interference patterns when 

scattered from structures as small as atoms to as large 

as biological cells. 

ENERGIES − of millielectronvolts, the same magnitude 

as atomic motions. Exchanges of energy as small as nanoelectronvolts and as large as tenths of electronvolts can be 

detected between samples and neutrons, allowing motions 

in folding proteins, melting glasses and diffusing hydrogen 

to be measured. 

SELECTIVITY − in scattering power varies from nucleus to 

nucleus somewhat randomly. Specific isotopes can stand 

out from other isotopes of the same kind of atom. Specific 

light atoms, difficult to observe with X-rays, are revealed 

by neutrons. Hydrogen, especially, can be distinguished 

from chemically equivalent deuterium, allowing a variety 

of powerful contrast techniques.

MAGNETISM − makes the neutron sensitive to the magnetic 

moments of both nuclei and electrons, allowing the structure 

and behavior of ordinary and exotic magnetic materials to be 

detailed precisely. 

NEUTRALITY − of the uncharged neutrons allows them 

to penetrate deeply without destroying samples, passing 

through walls that condition a sample’s environment, 

permitting measurements under extreme conditions of 

temperature and pressure. 

CAPTURE − characteristic radiation emanating from specific 

nuclei capturing incident neutrons can be used to identify 

and quantify minute amounts of elements in samples as 

diverse as ancient pottery shards and lake water pollutants.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 1THE NIST CENTER FOR NEUTRON RESEARCH
NIST Center for Neutron Research Instruments (as of December 2014)

[1] BT-5 Perfect Crystal Ultra-Small Angle Neutron 

Scattering (USANS) Diffractometer for microstructure 

up to 104 nm. 

[2] BT-4 Filter Analyzer Neutron Spectrometer with 

cooled Be/Graphite filter analyzer for chemical 

spectroscopy and thermal triple axis spectrometer.

[3] 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 and DOE.

[4] BT-1 Powder Diffractometer with 32 detectors; 

incident wavelengths of 0.208 nm, 0.154 nm, and 

0.159 nm, with resolution up to Δd/d ≅ 8 x 10-4.

[5] BT-9 Multi Axis Crystal Spectrometer (MACS II), a

cold neutron spectrometer for ultra high sensitivity 

access to dynamic correlations in condensed matter on 

length scales from 0.1 nm to 50 nm and energy scales 

from 2.2 meV to 20 meV.

[6] BT-8 Residual Stress Diffractometer optimized 

for depth profiling of residual stresses in large 

components.

[7] BT-7 Thermal Triple Axis Spectrometer with large 

double focusing monochromator and interchangeable 

analyzer/detectors systems.

[8] VT-5 Thermal Neutron Capture Prompt Gammaray Activation Analysis Instrument with a neutron

fluence rate of 3 x 108 cm-2 s-1 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.

[9] NG-A Neutron Spin-Echo Spectrometer (NSE) 

for measuring dynamics from 5 ps to 100 ns.

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), 

5 (MACS II), 9 (NSE), 11 (NG-B SANS), 18 (HFBS), and 19 (DCS).

2 NIST CENTER FOR NEUTRON RESEARCH NIST CENTER FOR NEUTRON RESEARCH INSTRUMENTS
[10] NG-B 10 m SANS for macromolecular structure 

measurements. 

[11] NG-B 30 m SANS for microstructure measurements. 

[12] NG-C aCORN Neutron physics station for measurement of the correlation parameter between the 

electron and anti-neutrino in neutron beta decay.

[13] NG-D Cold neutron capture Prompt Gamma 

Activation Analysis, for quantitative elemental 

analysis of bulk materials, especially of 

hydrogenous ones.

[14] NG-D MAGIK off-specular reflectometer for studies 

of thin-film samples with in-plane structure.

[15] NG-D Polarized Beam Reflectometer (PBR) 

for measuring reflectivities as low as 10-8 to 

determine subsurface structure.

[16] NG-1 Cold Neutron Depth Profiling for profiling 

of subsurface elemental composition.

[17] NG-1 Detector development station.

[18] NG-2 Backscattering Spectrometer (HFBS) high 

intensity inelastic scattering instrument with 

energy resolution < 1 μeV, for studies of motion 

in molecular and biological systems. 

[19] NG-4 Disk Chopper Time-of-Flight Spectrometer 

for diffusive motions and low energy dynamics. 

Wavelengths from ≅ 0.18 nm to 2.0 nm and energy 

resolutions from ≅ 2 meV to < 10 μeV. 

[20] NG-5 Spin-Polarized Triple Axis Spectrometer (SPINS) 

using cold neutrons with position sensitive detector 

capability for high-resolution studies.

[21-23] NG-6A Neutron Physics Station for precise 

measurement of the neutron magnetic dipole 

moment, neutron flux, and neutron lifetime.

[24] NG-7 30 m SANS for microstructure measurements, 

in partnership with ExxonMobil and University of 

Minnesota’s IPrime.

[25] NG-7 Cold neutron capture Prompt Gamma 

Activation Analysis, for quantitative elemental 

analysis of bulk materials.

[26] NG-7 Neutron Interferometry and Optics Station 

with perfect crystal silicon interferometer. A 

vibration isolation system provides exceptional 

phase stability and fringe visibility.

[27] NG-7 Neutron Physics Interferometry Test Bed 

for developing novel interferometry techniques.

[28] NG-7 Horizontal Sample Reflectometer allows 

reflectivity measurements of free surfaces, liquid/

vapor interfaces, as well as polymer coatings.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 3NIST CENTER FOR NEUTRON RESEARCH INSTRUMENTS
NCNR Images 2014

Pinaki Das (LANL) prepares the sample stage for his 

investigation of spin waves at MACS.

Md Taufique Hassan (Tulane U) at the NG6 Physics 

station conducting an aCORN experiment.

Students from Takoma Park Middle School (Silver Spring, MD) are wowed by a 

chain reaction as they learn about neutron science.

Chang Kyoung Choi and Jeffrey Allen (Michigan Technological U) after a successful 

experiment at the BT2 Neutron Imaging Facility.

Clinton Wiener and Melanie Longanecker (U Akron) prepare a new hydrogel 

sample for measurement at DCS.

Natasha Khatri (Georgetown U) is mounting her molecular magnet sample for 

a polarized beam experiment at the NGD reflectometer.

Mike Rinehart (bottom) and Doug Ogg of the NCNR 

carefully remove the neutron guides from the NG3 

SANS instrument in preparation for its move to NGB.

4 NIST CENTER FOR NEUTRON RESEARCH NCNR IMAGES 2014
Danny Liu (Ohio State U) is ready to take some data at the cold neutron depth 

profiling instrument.

Three generations of NCNR directors: Mike Rowe, Pat Gallagher, and Rob Dimeo 

(L-R) together at Pat’s farewell cookout.

Zhijun Xu (UC Berkeley) makes some final adjustments to the sample environment 

at BT7 before he starts his experiment.

Dan Sunday (NIST MSED) carefully loads his samples into the sample chamber 

at NGB 10m SANS.

Jeff Lynn (NCNR) explains to an interested group of students from Springbrook 

High School (Silver Spring, MD) how scientists use neutrons to “see” materials.

Doug Godfrin (U Delaware), Chris Bertrand (NCNR), Richard Menendez (Northwest 

HS), and Koty McAllister (U Delaware) (L-R) at the NGB 30m SANS. The three 

supervisors are making sure that Chris is connecting the electrodes correctly.

Jason Rich (ORNL) is all smiles at NG7 30m SANS, especially when the 1-2 

shear cell is working.

At NSE, Koji Yoshida (L, Fukuoka U) is getting some help from Michihiro Nagao 

(NCNR) to set up his experiment scans.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 5NCNR IMAGES 2014
Revealing protein complexes 

at the lipid membrane

J. C. Lee1 and F. Heinrich2, 3

Neutron reflectometry is uniquely positioned within the 

available techniques in structural biology in that it allows 

the characterization of membrane-associated proteins close 

to their native cellular environment, even though it is of lower 

resolution than the dominant structural methods like protein 

crystallography, nuclear magnetic resonance, or cryo-electron 

microscopy. Neutron reflectometry allows routine studies of 

physiologically relevant, fluid phospholipid bilayers of complex 

structure and composition with full control of the aqueous buffer 

surrounding the membrane such as pH and the presence of other 

relevant biomolecules [1-3]. Structural responses such as protein 

conformational changes or the formation of a protein–co-factor 

complex at the membrane interface can be investigated in-situ. 

Recent improvements in reflectometry methods have enabled 

more detailed studies of membrane-bound protein-protein 

complexes and have been successfully applied to a biomedically 

relevant complex involving α-synuclein and glucocerebrosidase, 

proteins that are related to Parkinson and Gaucher diseases, 

respectively.

Several parallel developments at the NCNR have transformed 

neutron reflectometry into a powerful tool for structural biology 

over the last 5 years [4]. The introduction of a rigorous uncertainty analysis based on Monte Carlo methods paved the way for 

using complex molecular models for data analysis, ensuring that 

the information content of the experimental data is utilized to its 

maximum without over-fitting the data. For biological neutron 

reflectometry, this has lead to the retirement of the traditional 

box model and its replacement by a composition-space model 

(see Fig. 1) that directly models distributions of molecular groups 

while fully utilizing a maximum of prior information, such as 

known molecular volumes, scattering lengths, and chemical 

connectivity.

method to reveal envelopes of protein complexes, in which 

different molecular constituents have a different scattering length 

density, for example, due to a different degree of perdeuteration. 

This is implemented by adding an additional parameterization to 

the spline, not only describing the volume filling of the protein at 

every position, but also its scattering length density. The free-form 

1 Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892

2 Carnegie Mellon University, Pittsburgh, PA 15213

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

FIGURE 1: (A) Neutron reflectometry data and best-fit for a tethered lipid 

bilayer of palmitoyl oleoyl phosphatidylcholine (POPC) and palmitoyl oleoyl 

phosphatidic acid (POPA) at a composition of 50:50 POPC:POPA. The inset 

shows a scattering length density profile as it could be obtained using a box 

model. (B) Composition space model that describes the spatial distributions 

of molecular constituents of the tethered lipid bilayer by pairs of error 

functions; each POPC and POPA headgroups are modeled separately, as 

well as methylene and central methyl contributions from the hydrocarbon 

chains of the lipids. The tether is modeled using three chemically distinct 

distributions. Solvent occupies volume not filled by bilayer material.

The Monte Carlo uncertainty methods also enables a new way 

of modeling protein envelopes using free-form spline functions 

(see Fig. 2). By itself, a fit to the data using a spline function is not 

very convincing because the uniqueness of the solution cannot 

be assessed. In combination with a rigorous uncertainty method, 

however, accurate confidence intervals on the spline envelope 

can be determined, transforming the spline fitting into a useful 

tool to describe unknown or disordered structural features of a 

protein. A recent advance is the extension of the spline fitting 

6 NIST CENTER FOR NEUTRON RESEARCH BIOLOGY
scattering length density that has been obtained in this way can 

be mathematically decomposed into contributions from each 

constituent, thus obtaining individual envelopes. 

The first biological application of this method was to elucidate 

the membrane-bound complex of α-synuclein, an intrinsically 

disordered neuronal protein implicated in Parkinson disease, and 

glucocerebrosidase, a lysosomal enzyme that causes Gaucher 

disease and is associated with a higher risk for the development 

of Parkinson disease. Current research is focused on defining 

the underlying mechanism for the genetic relationship between 

glucocerebrosidease and Parkinson disease in the search of a 

new therapeutic approach for this devastating ailment. The 

complex formation between the two proteins within the lysosome 

offers one such molecular connection. In recent work, we have 

confirmed that, indeed, the two proteins form a complex at the 

membrane, and we were able to derive a structural model for the 

complex that is in agreement with the neutron reflectometry data 

and additional fluorescence data (see Fig. 3) [5]. Although our 

data do not preclude protein-protein interactions in other cellular 

milieux, we suggest that the α-synuclein–glucocerebrosidase association is favored in the lysosome both on and off intralysosomal 

membranes, and that this noncovalent interaction provides the 

groundwork to explore molecular mechanisms linking Parkinson 

disease with mutant glucocerebrosidase.

References

[1] F. Heinrich, H. Nanda, H. Z. Goh, C. Bachert, M. Lösche, 

A. D. Linstedt, J. Bio. Chem. 289, 9683 (2014).

[2] C. M. Pfefferkorn, F. Heinrich, A. J. Sodt, A. S. Maltsev, 

R. W. Pastor, J. C. Lee, Biophys. J. 102, 613 (2012).

[3] S. Shenoy, P. Shekhar, F. Heinrich, M.-C. Daou, A. Gericke, 

A. H. Ross, M. Lösche, PLoS ONE 7, e32591 (2012).

[4] F. Heinrich, M. Lösche, Biochim Biophys. Acta 1838, 2341 (2014).

[5] T. L. Yap, Z. Jiang, F. Heinrich, J. M. Gruschus, M. Barros, 

C. M. Pfefferkorn, J. E. Curtis, E. Sidransky, J. C. Lee, 

(submitted to EMBO Reports, 2014).

FIGURE 2: The structural envelope of the time and ensemble average of 

α-synuclein at a solution concentration of 3 μmol/L associated with a 

tethered lipid membrane composed of 50:50 POPC:POPA lipids at pH 7. The 

envelope has been modeled using a free-form monotonic Hermite spline 

defined by 11 control points, originally spaced apart by 20 Å. In addition to 

being free to assume any volume occupancy, each control point is allowed 

to deviate from its original position by ±7 Å during the fit. 68 % confidence 

limits are shown for the protein envelope. The median envelope peaks in 

the headgroup region and extends approximately 60 Å into the bulk solvent 

phase. A significant penetration of the protein into the hydrocarbon region 

of the bilayer is observed.

FIGURE 3: A structural model of α-synuclein and glucocerebrosidase-based 

neutron reflectivity data of perdeuterated α-synuclein and protated glucocerebrosidase associated with a tethered lipid membrane composed POPC 

and palmitoyl oleoyl phosphatidylserine (POPS) at a composition of 50:50 

POPC:POPS at pH 5.5. Both protein concentrations were at 300 nmol/L. 

The orientation of glucocerebrosidase at the membrane was determined 

using a rigid-body model based on X-ray crystal structure as previously 

described for other systems [1]. The placement of α-synuclein with respect 

to the enzyme and the bilayer was based on best fit to the measured neutron 

density distribution for the complex.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 7BIOLOGY
A sticky situation: antibody adsorption, desorption 

and aggregation at solid-liquid interfaces

H. Nanda,1,2 T. V. Nanda,3,4 D. P. Nesta,3 and C. J. Roberts4

P

rotein based therapeutics, especially those centered on 

monoclonal antibodies, are a fast growing area of drug 

development due to their high target-specificity and therefore generally lower toxicity. However, aggregation of proteins is 

a common issue during product development and manufacturing, as well as during subsequent transportation and storage [1]. 

Protein aggregation mediated by partial unfolding can be 

accelerated by inadvertent stresses, such as agitation, exposure to 

elevated temperatures, chemical degradation, and even exposure 

to solid-liquid and liquid-water interfaces (e.g. the inside surface 

of a glass vial or at the air-water interface of trapped bubbles 

in a tube) [2]. Large aggregate formation is a concern not only 

due to the potential loss in efficacy and shelf life of a drug but 

also due to the potential triggering of unwanted and possibly 

life-threatening immunogenic responses in patients [3].

Association of proteins at bulk interfaces has been empirically 

implicated in aggregate formation for some proteins but the 

mechanistic details of the process are not fully known, at least in 

part, because a majority of characterization techniques measure 

protein structure and aggregation state only in bulk solution. 

Therefore the nature of the protein layer at the surface, how 

its structure changes due to desorption and the correlation 

with aggregate particle formation in solution are all poorly 

understood. To target these questions, the interaction of a 

monoclonal antibody IgG1 with a hydrophilic SiOx surface has 

been studied using the unique surface characterization technique 

of neutron reflectivity (NR). Solution-based methods such as micro 

flow imaging (MFI) were then used to connect protein surface 

structure to aggregate particle formation in the aqueous phase.

A schematic of the experimental setup and procedure is shown 

in Fig. 1. Interpretation of the NR data provides a 1-D profile of 

the protein density distributed along the surface normal (z-axis) 

direction from the SiOx layer. To take advantage of the sensitivity 

of neutrons to the isotopic state of hydrogen, all measurements 

were repeated in both H2O and D2O buffer solution and the data 

were fit simultaneously to a single protein profile structure. 

shows the resulting protein layers derived from the NR measurements. At pH 4.5, for both salt conditions, the IgG1 molecules 

form a narrow single-peak distribution on the SiOx surface with 

dimensions consistent with a ‘flat-on’ orientation as depicted in 

Fig. 2A, insert. At pH 6.2 an alternate layer structure is observed 

for the low salt condition (Fig. 2B). The broad distribution with a 

secondary peak can be interpreted as a protrusion of a protein 

lobe from the surface (Fig. 2B, inset). However the profile could 

also be due to multiple protein orientations and further measurements are required to distinguish between these cases. 

During the desorption steps, the structure is unchanged and very 

little of the protein layer is removed at pH 4.5, indicating a strong 

surface interaction. Conversely, at pH 6.2, desorption resulted in 

20 % to 30 % of the protein layer removed. This IgG1 molecule 

was shown to carry a +15e charge at low pH and a greater than 

3-fold reduction in surface charge at high pH, [4] suggesting electrostatics play a significant role in promoting surface interactions 

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

2 Carnegie Mellon University, Pittsburgh, PA 15213

3 Department of Biopharmaceutical Technologies, GlaxoSmithKline, King of Prussia, PA 19406

4 Department of Chemical & Biomolecular Engineering, and Center for Molecular and Engineering Thermodynamics, University of Delaware, Newark, DE 197116

FIGURE 1: Schematic of the flow cell used for protein adsorption/desorption 

experiments and the scattering geometry for neutron reflectivity (NR) 

measurements. Stock solutions of mAb flow over the surface of a thin 

SiOx film (layer 2) that forms natively on the underlying Si wafer substrates 

(layer 1). Adsorption of mAb occurs on the hydrophilic SiOx surface forming 

a protein film (layer 3) and is structurally characterized by NR. Desorption 

of the protein layer was performed by a subsequent rinse with pure buffer. 

The protein film structure was also studied by NR after desorption. The 

collected rinse fractions are analyzed for aggregate particle formation on 

a Micro-flow Imaging (MFI) instrument.

IgG structure at the SiOx surface was measured at two different 

pH values, 4.5 and 6.2 and two salt concentrations, 0 mmol/L 

and 100 mmol/L NaCl resulting in four buffer conditions. Fig. 2 

8 NIST CENTER FOR NEUTRON RESEARCH BIOLOGY
of the IgG1 protein with the negative surface charge density of 

the SiOx layer. On the other hand, the maximum surface coverage 

at pH 6.2 was comparable or higher than for the lower pH despite 

the weaker adsorption. The reduced net charge on IgG1 at pH 

6.2 would allow for closer packing on the surface despite the 

low surface interaction energy.

Combining neutron reflectivity with solution-based techniques 

has allowed the correlation between protein layer structure 

and aggregate formation to be investigated. The results of 

this work clearly indicate that exposure to the SiOx surface 

accelerated particle aggregate formation similar to thermally 

induced aggregation of IgG1 previously reported [4]. The surface 

density of proteins, the layer structure and the amount of 

desorption are highly dependent on pH and salt conditions of 

the buffer and likely stem from the interplay of protein-protein 

and protein-surface interactions. The balance of these factors as 

a function of surface properties and protein sequence provides 

valuable information in guiding formulation strategies for 

manufacturing and storage of protein based therapeutics.

References

[1] E. Y. Chi et al., Pharm. Res. 20, 1325 (2003).

[2] W. Norde et al., Adv. Colloid. Interface Sci. 179-182, 5 (2012).

[3] S. K. Singh, J. Pharm. Sci., 100, 354 (2011).

[4] R. K. Brummitt et al., J. Pharm. Sci., 100, 2087 (2011).

FIGURE 2: Area profiles derived from NR experiments show the pH and 

salt dependence of the IgG1 layer structure on SiOx surfaces. All protein 

solutions consisted of 30 mmol/L citrate buffer and 15 mg/mL IgG. A 1-D 

protein density along the surface normal direction is given in terms of an 

area fraction for both the adsorption step (green) and the desorption step 

(yellow), dashed lines represent 2σ confidence intervals. An illustrative 

molecular model of the protein profiles are depicted as insets in (A) and (B).

FIGURE 3: Particle size and shape analysis from MFI measurements of 

IgG1 solutions before and after exposure to the SiOx surface. (buffer: pH 4.5 

30 mmol/L citrate, 0 mmol/L NaCl). Contour plots indicate the frequency 

particles were counted with a certain equivalent circular diameter (ECD) and 

aspect ratio. Samples taken from the stock solution, first buffer rinse after 

SiOx exposure and the second buffer rinse are shown in panels (A), (B), and 

(C) respectively. (D) shows characteristic images of the large (> 30 μm ECD) 

particles observed in the second buffer rinse sample.

The morphology of large particle aggregates was assessed by 

MFI. At pH 6.2 the formation of soluble aggregates were not 

detected. In previous work it was shown for this molecule in 

solution that thermally accelerated aggregation resulted in 

macroscopic, insoluble particles at pH values greater than 5.5 [4]. 

Therefore these aggregates are not expected to be detectable 

by MFI. At pH 4.5 soluble aggregate formations did occur and 

was monitored by MFI as shown in Fig. 3 for the 0 mmol/L NaCl 

sample. The stock solution showed < 0.03 % particle formation by mass and those particles detected were all found to be 

< 10 μm in diameter and spherical in morphology (Fig. 3A). After 

exposure to the SiOx surface, the particle number increased by 

an order of magnitude and was significantly more asymmetric 

although sizes remained small (Fig. 3B). The second rinse fractions 

showed another increase in particle number as well as the formation of large elongated particle aggregates, > 30 μm in diameter 

(Fig. 3C). Images of the large particles indicated fibrillar-like 

shapes (Fig. 3D). Thioflavin T fluorescence assays found strong 

dye binding suggesting high beta sheet amyloid content in the 

second rinse solutions (data not shown).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 9BIOLOGY
Determination of monoclonal antibody conformation 

using SANS and refined using free energy constraints

N. J. Clark,1 H. Zhang,1 S. Krueger,1 H. J. Lee,2 R. R. Ketchem,2 B. Kerwin,2 S. R. Kanapuram,2 M. J. Treuheit,2

A. McAuley,2 and J. E. Curtis1

Over the past 30-plus years the biotechnology industry has 

mastered protein engineering, cloning and cell culture 

techniques that make designing and producing therapeutic 

antibodies with a singular, monoclonal, specificity an exciting 

reality. To date, many antibody therapeutics have been or are in 

the process of being approved by the FDA and they represent 

one of the fastest growing classes of pharmaceutical drug 

products. The use of therapeutic antibodies for the treatment 

of many cancers, allergy conditions and autoimmune diseases 

are underway and they represent a promising form of treatment 

to patients everywhere.

Biotechnology companies are striving to produce highly concentrated ( > 100 mg/mL) patient-injectable antibody solutions. 

Occasionally, certain formulations of antibody solutions fail due to 

gradual formation of large potentially immunogenic aggregates, 

spontaneous crystallization and even phase separation. A greater 

understanding of the processes that lead to the above-mentioned 

phenomena would insure safety and increase shelf life for protein 

therapeutics. 

Structurally, an antibody is a dynamic protein best described as 

having three distinct lobes, which can move independent of each 

other and yet are held in a Y-shape arrangement by a hinge-like 

junction (two identical Fab-lobes connected to an Fc-lobe). The 

built-in flexibility and the size of monoclonal antibodies, both 

of which are necessary for function, represent a challenge for 

structural studies. Here we have combined small-angle scattering 

with atomistic modeling to better define the possible conformations or lobe orientations that exist in solution [1]. Using simulation software developed at the NCNR [2], we have generated a 

full-atom ensemble of antibody orientations to compare to small 

angle neutron scattering (SANS) and X-ray scattering (SAXS) data 

of dilute antibody solutions.

Monoclonal Anti-Streptavidin Immunoglobulin G2 (ASA-IgG2) 

antibody was obtained from Amgen as a highly purified 

concentrated solution (30 mg/mL). ASA-IgG2 was shown to 

be unaggregated monomer (98 % monomer) by size-exclusion 

coupled multi-angle light scattering (SEC-MALS) over several 

concentrations ranging from (1 to 5) mg/mL. The average solution 

conformation of ASA-IgG2 was then evaluated using SANS at a 

concentration of 2.0 mg/mL, which was determined to be free 

from interparticle interactions. For the 2.0 mg/mL ASA-IgG2 the 

radius of gyration was measured using SANS to be 47.5(6) Å. 

The pair distribution, P(r), plot of ASA-IgG2 gave a maximum 

dimension of the average ASA-IgG2 molecule of 155 Å. The 

resulting real-space Rg was 48 Å and is in agreement with that 

found using the Guinier approximation. 

Molecular simulations were performed using an atomistic 

coordinate model based on the ASA-IgG2 amino acid sequence. 

The program SASSIE [2] was used to generate 56,511 unique, 

non-overlapping structures. To do so, SASSIE sampled backbone 

dihedral angles, Ψ or φ, of three amino acids within the hinge 

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

2 Amgen Inc., Process and Product Development, Thousand Oaks, CA 91320

FIGURE 1: Schematic representation of an immunoglobulin G (IgG) 

subclass 2, isotype A protein. IgG is composed of two light chains (LC) 

and two heavy chains (HC) that are held together through several inter- and 

intrachain disulfide bonds (S-S) and non-bonding interactions. The LC and 

part of the HC form two identical Fab domains. Part of each HC also forms 

a single FC domain. The Fab and Fc domains are connected via a flexible 

hinge region (blue) that has four interchain disulfide bonds. The parts of 

the hinge regions varied in Monte Carlo simulations are represented by 

heavy dashed black lines.

10 NIST CENTER FOR NEUTRON RESEARCH BIOLOGY
region adjacent to each Fab lobe (see Fig. 1). Theoretical scattering 

profiles for each structure were calculated [3] and the resulting 

I(q)-plots were compared with the 2 mg/mL SANS data. 

Even though only three amino acids were used for dihedral angle 

sampling for both Fab-lobes, the relative configurations between 

the Fab to Fc domains varied quite drastically. The resulting 

orientations had Rg-values that spanned from ≈ 39 Å to ≈ 55 Å. 

However, the best-fit structures, those with χ2 ≤ 2, had an Rg

that were confined to a range of ≈ 46.5 Å to ≈ 50.5 Å. Overlaying 

the atomistic density, occupied for all the structures in the full 

ensemble and the sub-ensemble (those with χ2 ≤ 2) allows a visual 

inspection of the conformational space available to ASA-IgG2. 

Density-plots for the full- and sub-ensemble are represented 

in Fig. 2.

techniques like analytical ultracentrifugation (AUC), nuclear 

magnetic resonance (NMR) and Förster Resonance Energy 

Transfer (FRET) provide those constraints. 

Another approach is to apply a free-energy analysis to evaluate 

the relative configurational energies of the sub-ensemble of 

ASA-IgG2. As shown in Fig. 3a, the relative free energy, ΔG°, 

of the sub-ensemble (structures with χ2 < 2) shows that fewer 

configurations may be energetically favorable. Evaluation of 

structures near the energetic minimum could allow a substantial 

reduction of the number of plausible, and hence representative, structures. Alternatively, evaluation of structures near the 

energetic maximum may help to evaluate regions that lead to 

undesirable intramolecular interactions.

The energetic analysis, while computationally demanding and 

inherently limited, includes thermodynamic constraints that have 

the potential to improve upon the results of conservative linear 

combinations of scattering profiles used to calculate the ensemble 

of structures depicted in density-plots in Fig. 2. Evaluation of 

molecular conformations present in dilute antibody solutions is 

an important prerequisite step for understanding how antibodies 

behave in more complicated concentrated solutions. The methods 

developed for this study are currently being applied to solutions 

with concentrations as high as 200 mg/mL. In conjunction with 

orthogonal experiments our goal is to better describe the types 

of interactions present in solution in order to better design safe, 

effective therapeutic proteins. 

References

[1] N. C. Clark et al., J. Phys. Chem. B 117, 14029 (2013).

[2] J. E. Curtis et al., Comput. Phys. Commun. 183, 382 (2012).

[3] S. Krueger et al., J. Biol. Chem. 273, 20001 (1998).

FIGURE 3: Relative configurational free-energy analysis of structures with 

χ2 < 2. (a) Molecular mechanical energy (MM), non-polar solvation energy 

(ΔGS), and total free energy (G°) for 1160 structures. (b) Iso-density plot 

of ASA-IgG2 (reproduced from Fig. 2c). (c) Iso-density plot of structures 

of lowest free energy within one standard deviation of the lowest single 

free-energy value in the ensemble. Parts (d) and (e) show structures with 

the single highest and lowest free energy, respectively.

The “best-fit” structures contained within the sub-ensemble 

number approximately 1200 of the > 56,000 structures. 

Constraints from additional experimentation offer a means 

to further refine the possible conformations and to further 

clarify structure function relationships. Orthogonal biophysical 

FIGURE 2: Iso-density plots of ASA-IgG2 from molecular Monte Carlo 

simulation. (a) Starting structure. (b) The solid surface representation of all 

structures. (c) The solid surface representation for structures with χ2 < 2.0. 

Structures were aligned on their Fc region (brown) in order to demonstrate 

the configuration space covered by the flexible Fab arms (Fab light chain, 

red; Fab heavy chain, gray).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 11BIOLOGY
Tunable CO/H2 and CO/N2 separations in metalorganic frameworks with exposed divalent metal 

cations via reversible CO binding

M. R. Hudson,1 C. M. Brown,1,2 E. D. Bloch,3 J. A. Mason,3 S. Chavan,4 V. Crocellà,4 J. D. Howe,5,6 K. Lee,5,6

A. L. Dzubak,7 W. L. Queen,6 J. M. Zadrozny,3 S. J. Geier,3 L.-C. Lin,5 L. Gagliardi,7 B. Smit,3,5,8 J. B. Neaton,6,8

S. Bordiga,4 and J. R. Long3,8

C

arbon monoxide has become an increasingly important 

chemical for the synthesis of a variety of chemical commodities, including many monomers and polymers, ethanol and 

other alcohols, and acetic acid. There are currently a number 

of competing technologies for its synthesis, the main products 

of which are carbon monoxide and hydrogen (syngas), typically 

present in H2:CO ratios between 1 and 3. To use carbon monoxide 

as a feedstock, the ratio must be reduced. Although energy-intensive cryogenic distillation is currently employed to separate these 

mixtures, a number of alternative methods, including membrane and 

adsorptive separations, have recently been investigated for use in 

the production of pure carbon monoxide. Given their high density of 

coordinatively-unsaturated metal cation sites, metal-organic frameworks of the M2(dobdc) structure type (M = Mg, Mn, Fe, Co, Ni, Zn; 

dobdc4- = 2,5-dioxido-1,4-benzenedicarboxylate) hold considerable 

promise for the adsorptive separation of gas streams, including 

mixtures of CO2/N2, CO2/H2, O2/N2, CH4/N2, paraffins/olefins, and 

stand poised for the separation of gas mixtures containing CO [1-3]. 

The coordination of carbon monoxide to transition metals has 

been rigorously investigated for over a century, and has played 

an essential role in the development of our understanding of 

chemical bonding. Carbonyl complexes have been isolated and 

characterized for nearly every transition metal, in varying oxidation 

states and overall coordination numbers. The vast majority of 

these species feature CO irreversibly bound to low-valent, low-spin 

transition metal centers that are able to engage in the metal-to-CO 

π-backbonding required for strong binding. For systems in which 

π-backbonding is absent or diminished, carbonyl complexes remain 

elusive. With this work, we show that CO can reversibly bind to 

the coordinatively-unsaturated M2+ cations lining the surfaces 

within the metal-organic frameworks M2(dobdc), providing the first 

crystallographically characterized magnesium and zinc carbonyl 

compounds and the first high-spin Mn(II), Fe(II), Co(II), and Ni(II) 

carbonyl species. The metal-organic framework lattice likely helps 

to maintain a high-spin state, as these materials would have to 

undergo significant structural changes to accommodate the smaller 

low-spin M2+ ions. As a result, these materials can be anticipated 

to display weak to moderate CO binding and complete reversibility, 

a property that could potentially be exploited for removing CO from 

various gas mixtures.

As an initial probe of the interaction of CO with the square 

pyramidal M2+ cations lining the ≈ 12 Å wide channels in 

M2(dobdc), we turned to in-situ infrared (IR) spectroscopy. For 

all 6 frameworks, a single adsorption band is observed at low 

coverage between 2160 cm-1 and 2178 cm–1, which is blue-shifted 

with respect to the stretching mode of free CO (2143 cm–1). For 

classical transition metal carbonyl complexes, the average υ(CO) is 

red-shifted, because the M→CO π back-donation is the dominant 

effect, significantly weakening the C-O bond compared to that 

of free CO. When back-donation is absent or diminished, υ(CO) 

is blue-shifted in a phenomenon that is termed non-classical CO 

adsorption. Of the more than 20,000 reported M-CO stretching 

frequencies, only 250-300 can be considered non-classical.

Given our prior success in elucidating crystal structures of a number 

of adsorbent molecules in M2(dobdc) [1,2], we turned to neutron 

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

2 University of Delaware, Newark, DE 19716

3 Department of Chemistry, University of California, Berkeley, CA 94720

4 Department of Chemistry, NIS and INSTM Reference Centres, University of Turin, I-10135 Torino, Italy

5 Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720

6 The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720

7 Chemical Theory Center and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455

8 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720

FIGURE 1: A channel view (c-axis) of Fe2(dobdc)·1.5CO as determined by Rietveld analysis of powder neutron diffraction data (grey, carbon and red, oxygen) 

and coordination environment for a single Fe2+ site in Fe2(dobdc)·1.5CO. 

First coordination sphere for the M2+ ions in M2(dobdc)·1.5CO, with M–CO 

distances and M–C–O angles indicated.

12 NIST CENTER FOR NEUTRON RESEARCH CHEMICAL PHYSICS
powder diffraction experiments to further characterize the carbonyl 

adducts M2(dobdc)⋅1.5CO (Fig. 1). X-ray diffraction would be unable 

to distinguish the orientation of a CO molecule, but the difference 

in scattering cross sections are sufficient to allow this with neutrons. 

Consistent with the large range in CO IR stretching frequencies, we 

see a range of M-C-O angles, from 161.2(7)° for Zn to 176.9(6)° 

for Fe, with a strong correlation observed between υ(CO) and the 

M–C–O angle (Fig. 2). In the Fe and Co, where a greater degree 

of π-backbonding is observed via IR spectra, more linear carbonyl 

adducts are formed, while in the cases where electrostatic effects play 

a major role, bent structures are observed. The structures also display 

a large range in M-C bond distances, ranging from 2.09(2) Å for Ni 

to 2.49(1) Å for Zn, with excellent correlation between adsorption 

enthalpy and M-C distance (Fig. 2). Both Ni(II)- and Co(II)-carbonyl 

are rare and feature low-spin metal cations and short M-C distances. 

Mg2(dobdc)⋅1.5CO and Zn2(dobdc)⋅1.5CO, d(M-CO) = 2.41(2) and 

2.49(1) Å, respectively, represent the first crystallographically characterized Mg and Zn carbonyl complexes, regardless of oxidation state. 

Magnetic susceptibility data were also collected to confirm the 

high-spin character of the iron(II) centers in the CO-adsorbed phase 

Fe2(dobdc)·2CO. Mössbauer spectra further confirm the assignments 

of high-spin Fe(II). The result for Fe2(dobdc)·2CO is without precedent. Of the nearly 9,000 iron-carbonyl structures reported in the 

Cambridge Crystal Structure Database, only three are paramagnetic, 

all featuring intermediate-spin (S = 1) Fe(II) centers in a trigonal 

bipyramidal coordination environment, for which an S = 0 spin state 

is generally not possible. Thus, Fe2(dobdc)·2CO represents the first 

example of a paramagnetic octahedral iron carbonyl compound and, 

to our knowledge, the first reported S = 2 iron carbonyl. 

To probe the ability of these compounds to separate gases and 

purify CO, we measured pure component CO adsorption isotherms 

at 298 K, 308 K, and 318 K, and isosteric heats of adsorption were 

calculated for each metal. At 298 K, the CO adsorption isotherms for 

the Fe, Co and Ni frameworks approach the value expected for one 

CO molecule per open metal site. Importantly, in all cases, the bound 

CO could be completely desorbed upon application of dynamic 

vacuum and/or heat, and subsequent CO adsorption isotherms 

showed no loss of uptake capacity. The isosteric heats of adsorption 

calculated from the data vary widely with metal; the CO binding 

strength following the order Ni > Co > Fe > Mg > Mn > Zn (Fig. 2). 

The extraordinary ability of these materials to bind CO reversibly and 

at high capacity does suggests their potential application in removing 

CO from gas mixtures, such as CO/N2 and CO/CH4, and, in particular, for the purification of CO from syngas. In order to determine 

the CO/H2 selectivities, we employed ideal adsorbed solution theory 

(IAST). To reflect the varying H2:CO ratios found in syngas, IAST 

selectivities were calculated over a range of compositions (Fig. 3), 

and were found to vary widely, from a minimum of 45 in the case of 

Zn2(dobdc) to over 5200 for Ni2(dobdc) at low CO concentrations. 

The high CO/N2 selectivities of these materials also bodes particularly 

well for use in separating CO from syngas contaminated with N2.

FIGURE 2: Variations of M–CO distance (neutron diffraction, black diamonds) 

and isosteric heat of CO adsorption (Qst, blue circles) and of M–C–O angle 

(neutron diffraction, black diamonds) and C–O stretching frequency (FTIR, 

blue circles) with M2+ in M2(dobdc). Error bars indicate the one standard 

deviation in the diffraction refinements.

FIGURE 3: IAST selectivities for CO/H2 and CO/N2 mixtures (298 K, 1 bar) 

for 6 different M2+ species.

M2(dobdc) type metal-organic frameworks provide an excellent 

platform for the investigation of new coordination chemistry via 

gaseous substrate binding at coordinatively-unsaturated metal 

sites. The fully reversible CO binding at high capacity and moderate 

adsorption enthalpies further make these materials outstanding 

candidates for the efficient separation of CO gases such as H2 and 

N2. The rigidity of the evacuated materials, together with their highly 

crystalline nature, has thus enabled the generation and crystallographic characterization of the first high-spin Mn(II), Fe(II), Co(II), 

and Ni(II) carbonyl species, as well as the first magnesium and zinc 

carbonyls. Neutron diffraction, and the ability to fully differentiate 

C and O atoms, is critical to making this possible.

References

[1] S. J. Geier et al., Chem. Sci. 4, 2054 (2013).

[2] E. D. Bloch et al., Science 335, 1606 (2012).

[3] E. D. Bloch et al., J. Am. Chem. Soc. ASAP, DOI: 10.1021/

ja505318p.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 13CHEMICAL PHYSICS
Crystal and magnetic stripes coupled to 

cooperative Jahn-Teller effects in Na5/8MnO2

X. Li,1 X. Ma,1 D. Su,2 L. Liu,1 R. Chisnell,3 S. P. Ong,1 H. Chen,1 A. Toumar,1 J.-C. Idrobo,4 Y. Lei,1 J. Bai,5

F. Wang,6 J. W. Lynn,7 Y. S. Lee,3 and G. Ceder1

L

ayered oxides with alternating Na and transition metal layers 

have been studied extensively to understand their fundamental properties as well as for their potential application 

in rechargeable batteries, thermoelectrics, and as the parent 

materials of the superconductive cobaltates. Na can be electrochemically and reversibly removed from these materials in a 

process called de-intercalation, which can precisely control the Na 

concentration in the compound. The ordering of the unoccupied 

Na sites, or vacancies, is controlled by electrostatic interactions in 

the non-Jahn-Teller active systems. However, NaxMnO2 is expected 

to be more complicated as it mixes Mn3+ ions, which display one 

of the largest Jahn-Teller distortions in transition metal compounds 

and prefer nearest neighbor antiferromagnetic (AF) coupling, with 

Mn4+ ions, which are not Jahn-Teller active and can form either 

ferromagnetic or AF nearest neighbor couplings depending on the 

competition between different direct and indirect exchange mechanisms. The well-ordered Na5/8MnO2 material is a prototype for 

this class of systems, and we have carried out combined neutron, 

X-ray, and electron scattering measurements together with electronic calculations to unravel these intertwined interactions and 

provide a foundation to understand the important properties of 

this interesting and useful class of systems [1].

The Jahn-Teller (JT) effect refers to the local distortion of the 

chemical bonds around the Mn3+ transition metal ions, which lifts 

the degeneracy of the electronic configuration and lowers the 

energy of the system. The JT distortions can become correlated, 

resulting in the cooperative Jahn-Teller effect (CJTE) in complex 

(typically oxide) materials. The effect usually induces strong 

coupling between the charge, orbital and magnetic interactions, 

which control many important phenomena such as colossal 

magnetoresistance and superconductivity. For Na5/8MnO2, we 

find an unexpected superstructure with a pronounced static 

CJTE that is coupled to an unusual Na vacancy ordering. X-ray 

and electron scattering, plus the addition of neutron scattering measurements to elucidate the magnetic bonding were 

required to unravel the complex interactions in this prototype 

material. In particular, the magnetic order was found to consist 

of Mn interwoven magnetic stripes with different moments 

and magnetic couplings. This work demonstrates the strong 

Electrochemical Na de-intercalation from NaMnO2 initially occurs 

through a two-phase reaction, forming a new phase Na5/8MnO2

as illustrated in Fig. 1. The Na ordering was solved by a combination of different techniques including electron diffraction, 

scanning transmission electron microscopy (STEM) imaging, 

synchrotron X-ray diffraction (SXRD) and density functional theory 

(DFT) simulation. The Na layer of Na5/8MnO2 is formed by one 

full Na atomic stripe parallel to three half-full Na stripes in which 

Na and VNa (vacancies) alternate, with the Mn charge ordering 

reflecting the modulation of the Na ordering. There are three 

types of Mn stripes identified through magnetic neutron diffraction, electron energy loss spectroscopy in STEM mode and DFT 

simulation: a pure Mn3+ stripe, a pure Mn4+ stripe and a stripe 

of alternating Mn3+ and Mn4+ ions. As the Mn3+O6 octahedron 

is JT distorted and the Mn4+O6 is not, the periodic arrangement 

of these different stripes gives a CJTE, which can be directly 

1 Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139

2 Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973

3 Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139

4 Oak Ridge National Laboratory, Oak Ridge, TN 37831

5 National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973

6 Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, NY 11973

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

FIGURE 1: Na5/8MnO2 superstructure shows VNa ordering, Mn charge and 

magnetic stripe orderings. The magnetic spin-stripe ordering includes 

ferrimagnetic stripes (Ferri) and antiferromagnetic stripes (AF). The spin 

exchange parameters Jij between different Mn sites were calculated by 

density functional theory.

interaction between alkali ordering, electronic structure, and 

magnetic interactions, and underlines the essential role that 

structural details play in determining electronic behavior.

14 NIST CENTER FOR NEUTRON RESEARCH CHEMICAL PHYSICS
visualized by the rippling of the Mn layers from STEM imaging. It 

is worth noting that in the DFT-calculated structure, the Na ions 

in one of the three half-full Na stripes are displaced along the 

stripe direction by about 1.4 Å from their normal octahedral site 

location, into a new site. This stripe is labeled as NaDisp in Fig. 1. 

The local environment of the displaced Na ions is a highly distorted 

octahedral site face-sharing with both Mn4+O6 octahedra. The 

other Na sites in Na5/8MnO2 are normally slightly distorted octahedral sites that edge-share with both TM layers. The origin of 

the NaDisp displacement is that the relaxed Na ions to the highly 

distorted octahedral site can share the symmetric attraction of the 

two neighboring JT distorted -O-Mn3+-O-Na configurations.

One of the interesting consequences of the electronic and alkali 

ordering in Na5/8MnO2 is that it leads to a new and intriguing 

magnetic ordering. Based on neutron powder diffraction, magnetic 

susceptibility measurements and DFT calculations, we proposed 

the magnetic-stripe-sandwich structure shown in Fig. 1. The DFT 

total energies for different collinear magnetic spin orderings in 

Na5/8MnO2 were calculated and mapped onto a spin Hamiltonian, 

 to extract the nearest-neighbor and next-nearest-neighbor 

spin exchange parameters Jij between site i and j, as defined 

in Fig. 1. Si and Sj are the spin angular momentum operators. 

The result predicts the Mn3+ stripes to be AF, Mn4+ stripes to 

be ferrimagnetic, and mixed valence Mn3+/Mn4+ stripes to be 

ferrimagnetic with AF nearest-neighbor coupling.

Neutron diffraction measurements were performed on 5 g of 

chemically de-intercalated Na5/8MnO2 powder using the triple 

axis spectrometer BT-7 at the NIST Center for Neutron Research 

[2]. The diffraction pattern taken at T = 2.5 K reveals additional 

magnetic Bragg peaks compared with the diffraction pattern at 

T = 100 K (consisting of nuclear Bragg peaks from the crystal structure), demonstrating that the material exhibits long-range magnetic 

order. The inset in Fig. 2 shows the temperature dependence of 

the integrated intensity of the lowest angle magnetic Bragg peak, 

indicating an ordering temperature of T ≈ 60 K, consistent with the 

temperature of the upturn in the magnetic susceptibility. The DFT 

calculated coupling constant of -61.5 K (negative value corresponds 

to AF interaction) for the Mn3+ AF stripe is in good agreement with 

the temperature scale of the observed ordering.

The intensities of the magnetic Bragg peaks can be described by a 

pattern of magnetic stripes of ordered moments on the Mn sites. 

The simplest model of ordered moments consistent with the data 

involves AF stripes of Mn3+ with an AF coupling between stripes, as 

indicated by the blue arrows in Fig. 1. When only these moments 

are taken into account, the fits yield an ordered moment of 3.2(4) 

μB per Mn3+. Other magnetic ordering patterns which have the 

same periodicity as these AF Mn3+ stripes would also be consistent with the data. For example, AF stripes of Mn4+ and mixed 

Mn3+/Mn4+ coexisting with the AF stripes of Mn3+ would yield 

a similar magnetic diffraction pattern, but the average moment 

would have a smaller value of 2.2(3) μB per Mn. Further details of 

the magnetic structure will likely require measurements on single 

crystals. Interestingly, the divergence of the field-cooled and zerofield-cooled susceptibility curves around T = 12 K may indicate 

the presence of weakly coupled ferrimagnetic components and 

agrees quantitatively with the calculated nearest-neighbor coupling 

constant of 11.9 K for the Mn4+ ferrimagnetic stripes. Overall, the 

general pattern predicted by DFT of AF Mn3+ stripes interwoven 

with the Mn4+ and Mn4+/Mn3+ stripes is fully supported by the 

experiments. This new magnetic-stripe-sandwich structure may 

have potential application in magnetic storage or spin electronics 

as the 1D analogy to the sandwich structure of 2D magnetic thin 

films, from which abundant magnetic phenomena have been 

engineered. It is also worth noting that the dynamic version of 

the hole-segregated magnetic stripes has been proposed to be 

important for high temperature cuprate superconductors [3].

In summary, we have found Na5/8MnO2 to be a model system 

to visualize the complex interactions between Na ion/vacancy 

ordering, charge ordering, magnetic ordering and cooperative 

Jahn-Teller distortions. We find that in contrast to other alkali-vacancy systems, the Na ordering in NaxMnO2 is controlled by the 

underlying combination of electrostatic and electronic structure 

interactions through the Jahn-Teller effect, which enables some Na 

to occupy the highly distorted octahedral site. This leads to Na and 

Mn charge-ordered stripes, which in turn yields a fascinating low 

temperature magnetic ordering to develop. DFT and experimental 

observations are in excellent agreement, providing confidence in 

the proposed ground state and in the explanation for the physical 

origin of its stability. The understanding of the CJTE here may have 

general implications for understanding complex compounds where 

the Jahn-Teller effect is prominent, including intercalation energy 

storage materials and high temperature superconductors, and 

illustrates the fascinating physics of mixed Mn valence systems.

References

[1] X. Li et al., Nat. Mater. 13, 586 (2014).

[2] J. W. Lynn et al., J. Res. NIST 117, 61 (2012).

[3] M. Vojta, Adv. Phys. 58, 699 (2009).

FIGURE 2: Neutron diffraction and magnetic susceptibility measurement 

indicating magnetic stripe ordering. Magnetic Bragg peaks labeled by red 

arrows are seen in the 2.5 K spectrum compared to the 100 K spectrum. 

The inset shows the integrated intensity of the strongest magnetic peak in 

the neutron spectrum (left scale) and also the inverse magnetic susceptibility 

(right scale) versus temperature.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 15CHEMICAL PHYSICS
Anion reorientations, sodium mobility, and 

superionic conduction in Na2B12H12

N. Verdal,1,2 T. J. Udovic,1 J. J. Rush,1,2 W. S. Tang,1,2 J.-H. Her,3 A. V. Skripov,4 V. Stavila,5 M. Matsuo,6 and S. Orimo6

L

ight-metal dodecahydro-closo-dodecaborate (B12H122-) salts 

have received increased scrutiny in recent years because 

they are byproducts during the dehydrogenation of corresponding tetrahydroborates, such as LiBH4 and NaBH4, which 

are potential hydrogen-storage materials. More recently, we 

have discovered that thermal stability of B12H122- and its large 

size and quasispherical shape, which enable larger intralattice 

pathways for cation diffusion, are desirable qualities for its use 

in fast-ion conductor materials. Moreover, we have found that 

the lighter-alkali-metal compounds, Li2B12H12 and Na2B12H12, 

undergo entropy-driven transformations to disordered cubic 

phases exhibiting orientational disorder of the B12H122- anions and 

vacancy-rich cation sublattices that lend themselves to unusually 

facile cation diffusion. The unit cells of the low-temperature, 

ordered monoclinic (P21/n) and the high-temperature bcc (Im3m) 

structures of Na2B12H12 determined by neutron powder diffraction [1] are shown in Fig. 1. (It should be noted that Na2B12H12

passes through a partially disordered Pm3n phase at ≈ 529 K 

before achieving “full” Im3m disorder.) The orientational disorder 

of the anions is represented in Fig. 1b by a number of superimposed orientations. Also, in contrast to the ordered cation sites 

in Fig. 1a, the Na+ cations in the bcc phase are disordered among 

a complex array of off-center sites within the large interstices 

formed by the anions. This suggests the possibility of highly 

mobile Na+ cations capable of superionic conduction.

To probe the detailed nature of the dynamical disorder indicated 

by the diffraction results, we measured the reorientational 

behavior of the B12H122- anions and Na+ cation diffusion by 

combined quasielastic neutron scattering (QENS) [2] and NMR [3]. 

The QENS data were obtained using the DCS spectrometer at the 

NCNR at λ = 4.8 Å with 56 μeV FWHM resolution and a Q range 

up to 2.4 Å-1. In Fig. 2, we show the elastic incoherent structure factors derived from the QENS results at 580 K compared 

to a number of reorientational models, a representative QENS 

spectrum, and the schematics of two uniaxial jump models. 

A major conclusion of the model comparisons in Fig. 2 is that 

the B12H122- anions undergo predominantly uniaxial, small-angle, 

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

2 University of Maryland, College Park, MD 20742

3 GE Global Research, Niskayuna, NY 12309

4 Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia

5 Sandia National Laboratories, Livermore, CA 94551

6 Institute for Materials Research, Tohoku University, Sendai, Japan

FIGURE 2: The elastic incoherent structure factor (green symbols) measured 

at 580 K compared to several reorientational models. The uniaxial C4

(magenta dashes) and C6 (black dashes) jump reorientation models are 

shown schematically at the right. The 3-D tumbling model (gray dashes) 

mimics isotropic rotational diffusion. The solid blue line is a composite 

model of 50 % uniaxial C6 jumps, 30 % uniaxial C4 jumps, and 20 % 3-D 

tumbling. The inset shows a corresponding QENS spectrum at 1.2 Å-1. The 

fit (red) to the data (black) is comprised of elastic (white) and quasielastic 

(gray) contributions.

FIGURE 1: Unit cells of the (a) low-temperature, ordered monoclinic and 

(b) high-temperature, disordered cubic Na2B12H12 structures. Yellow, green, 

and pink spheres denote Na, B, and H, respectively.

16 NIST CENTER FOR NEUTRON RESEARCH CHEMICAL PHYSICS
reorientational jumps rather than 3-D tumbling motions, with 

6-fold jump reorientations around the anion 3-fold symmetry 

axes giving the best overall fit at 580 K. An even better fit can 

be achieved in Fig. 2 by assuming a small admixture of occasional 3-D tumbling to the predominantly uniaxial reorientations, 

acknowledging that there will be a distribution of rotational 

potentials within this highly disordered structure.

Additional information about the anion dynamical behavior was 

obtained by analyzing the quasielastic widths vs. temperature. 

The results, which are shown in Fig. 3 for both Na2B12H12 and 

Na2B12D12 (87 % deuterated), provide activation energies for 

reorientation of 259(22) meV and 252(7) meV, respectively. In 

a complementary study by 1H, 11B, and 23Na NMR spectroscopy, we have probed the B12H122- reorientational motions and 

Na+ diffusion in both the ordered and disordered phases. From 

proton spin-lattice relaxation data, respective activation energies 

of 770(20) meV and 270(40) meV were derived. NMR data 

confirmed a hundred-fold increase in reorientational jump rate 

(≈ 109 s-1 to ≈ 1011 s-1) at the phase transition. The analysis of the 

23Na spin-lattice relaxation data revealed a striking increase in 

Na+ diffusion jump rate at the order-disorder transition to a value 

of at least 2 x 108 s-1, indicating the possible onset of superionic 

conduction. See Refs. [2] and [3] for a complete analysis of the 

anion and cation dynamics in this compound.

To examine the implications of the great increase of anion reorientational and cation diffusional jump rates at the order-disorder 

transition in Na2B12H12, AC impedance measurements were carried 

out over a temperature range from 300 K to 575 K, including 

both cooling and heating scans [4]. The results are shown in 

Fig. 4, compared to other complex hydride materials. Hysteretic 

behavior is evident upon cooling, but the results clearly show a 

dramatic, nearly thousand-fold enhancement in conductivity upon 

transformation to the cubic phases. A conductivity of ≈ 0.1 S cm-1

near 550 K greatly exceeds that of all other complex-hydride 

materials to date. In fact, the conductivity of Na2B12H12 rivals that 

of sodium beta alumina, the current commercial electrolyte for 

Na-ion batteries operating in this temperature region. Aside from 

favorable conductivity, this material’s relative insensitivity to air, 

high-temperature stability, low cost, and simplicity of preparation 

make it worthy of further investigation.

Finally, as the research continues for analogous superionic electrolytes with improved properties, further work is required to reveal 

the mechanisms for fast cation diffusion. A direct comparison 

between different complex hydrides is clouded by differences in 

structures, anion valence numbers, anion/cation stoichiometric 

ratios, and the possible presence of mixed phases. Nonetheless, 

it is probable that the large, quasispherical B12H122- anions, and 

perhaps their reorientational mobility, provide for more facile 

cation pathways with lower barriers for diffusion.

References

[1] N. Verdal, J.-H. Her, V. Stavila, A. V. Soloninin, O. A. Babanova, 

A. V. Skripov, T. J. Udovic, J. J. Rush, J. Solid State Chem. 212, 

81 (2014).

[2] N. Verdal, T. J. Udovic, V. Stavila, W. S. Tang, J. J. Rush, A. V. 

Skripov, J. Phys. Chem. C 118, 17483 (2014).

[3] A. V. Skripov, O. A. Babanova, A. V. Soloninin, V. Stavila, N. 

Verdal, T. J. Udovic, J. J. Rush, J. Phys. Chem. C 117, 25961 

(2013).

[4] T. J. Udovic, M. Matsuo, A. Unemoto, N. Verdal, V. Stavila, 

A. V. Skripov, J. J. Rush, H. Takamura, S. Orimo, Chem. 

Commun. 50, 3750 (2014).

FIGURE 3: Arrhenius plots for Na2B12H12 (gray diamonds) and Na2B12D12 (blue 

circles) from which the activation energies for the reorientational motion 

were determined. Calculated jump frequencies are based on the C6 model.

FIGURE 4: Temperature dependence of the ionic conductivity of Na2B12H12

compared with that for other complex hydride materials (see Refs. in [4]).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 17CHEMICAL PHYSICS
Oxidation of ethane to ethanol by N2O in 

an iron(II) metal-organic framework 

M. R. Hudson,1 C. M. Brown,1,2 D. J. Xiao,3 E. D. Bloch,3 J. A. Mason,3 W. L. Queen,4 N. Planas,5 J. Borycz,5 A. L. 

Dzubak,5 P. Verma,5 K. Lee,4 F. Bonino,6 V. Crocellà,6 J. Yano,7 S. Bordiga,6 D. G. Truhlar,5 L. Gagliardi,5 and J. R. Long3,8

T

he selective and efficient conversion of light alkanes into 

value-added chemicals remains an outstanding challenge 

with tremendous economic and environmental impacts, 

especially given the recent worldwide increase in natural gas 

reserves. In nature, C–H functionalization is carried out by copper 

and iron metalloenzymes, which activate dioxygen and facilitate 

two- or four-electron oxidations of organic substrates through 

metal-oxo intermediates. Duplicating this impressive reactivity in synthetic systems has been the focus of intense research. 

Fe(IV)–oxo complexes have now been characterized structurally 

in various geometries (octahedral, trigonal bipyramidal) and spin 

states (S = 1, S = 2), and have proved to be competent catalysts for 

a variety of oxygenation reactions. In the absence of a protective 

protein superstructure, terminal iron–oxo species are highly susceptible to a variety of decomposition pathways. Tethering a molecular 

iron species to a porous solid support could potentially prevent 

many of these side-reactions. However, complexes heterogenized 

in this manner are difficult to characterize, and have problems 

with steric crowding, site inaccessibility and metal leaching. Iron 

cations can also be incorporated into zeolites to produce reactive 

iron centers. Fe-ZSM-5, for example, has been shown to oxidize 

methane to methanol stoichiometrically when pretreated with 

nitrous oxide. Characterization of these materials is nontrivial 

because of the presence of multiple iron species, and the nature 

of the active sites in Fe-ZSM-5 remains largely speculation.

The use of a metal–organic framework (MOF) to support 

isolated terminal iron–oxo moieties is a highly promising area 

of research [1,2]. The high surface area, permanent porosity, 

chemical and thermal stability, and synthetic tunability displayed 

by many of these materials makes them appealing in this regard. 

Additionally, MOFs are typically highly crystalline with well-defined 

metal centers suited for characterization by single-crystal and/

or powder-diffraction techniques. Of the 3-dimensional Fe(II)-

containing MOFs shown to be stable to desolvation, few possess 

coordinatively unsaturated metal centers in a single, well-defined 

environment. The compound Fe2(dobdc) (dobdc4- = 2,5-dioxido-1,4-benzenedicarboxylate) is rare in this regard, as the hexagonal channels of the framework are lined with a high density of a 

single type of square pyramidal, redox-active Fe(II) site (Fig. 1).

We embarked on a study of its reactivity towards nitrous oxide 

(N2O, molecular structure N≡N-O), a gaseous two-electron 

oxidant and O-atom transfer agent that is widely employed 

in industry, anticipating the generation of a highly reactive 

Fe(IV)–oxo species capable of oxidizing strong C–H bonds [1].

Experimental studies on the coordination chemistry of N2O are 

scarce, as metal–N2O adducts are challenging to synthesize 

because of the poor σ-donating and π-accepting properties of 

the molecule. Indeed, of the several proposed binding modes, 

only one (end-on, η1-N) has been structurally characterized in a 

molecular complex. To establish the coordination mode of N2O 

in Fe2(dobdc), powder neutron-diffraction data, which are very 

sensitive to the atomic assignment of O and N, were collected on 

a sample dosed with various loadings of N2O. At low loadings, 

the best fit was an average of approximately 60 % η1-O and 

40 % η1-N coordination, with Fe–N2O distances of 2.42(3) and 

2.39(3) Å, respectively (Fig. 1). In both cases, a bent Fe–N2O 

angle close to 120° was observed. Density functional theory (DFT) 

studies of N2O-bound Fe2(dobdc) show excellent agreement with 

experiment, predicting the η1-O mode to be favored over the 

η1-N mode by just 1.1 kJ mol−1. Although η1-O coordination with 

a bent Fe–O–N angle has been proposed in a variety of systems 

ranging from isolated metal atoms to iron zeolites, η1-N coordination with a bent Fe–N–N angle is much more unusual. The bent 

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

2 University of Delaware, Newark, DE 19716

3 University of California, Berkeley, CA 94720

4 The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720

5 Chemical Theory Center and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455

6 NIS and INSTM Reference Centres, University of Turin, I-10135 Torino, Italy

7 Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720

8 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720

FIGURE 1: (Left) Structure of Fe2(dobdc), showing hexagonal channels lined 

with five-coordinate Fe(II) sites. (Right) N2O binding in Fe2(dobdc) solved 

from powder neutron diffraction data (10 K). Orange, grey, dark blue and 

red spheres: Fe, C, N, O respectively.

18 NIST CENTER FOR NEUTRON RESEARCH CHEMICAL PHYSICS
geometry, long Fe–N2O bond length and mixed N and O coordination indicate that N2O is bound only weakly to the Fe(II) centers 

in the framework suggesting a physically adsorbed phase with 

little to no perturbation of the N2O molecule. As expected, this 

interaction is fully reversible under an applied vacuum. 

On heating the N2O-dosed framework to 60 °C, the material 

undergoes a drastic color change from bright green to dark red–

brown, suggestive of oxidation. Characterization of the resulting 

product is consistent with the formulation Fe2(OH)2(dobdc), in 

which each iron center is in the +3 oxidation state and bound 

to a terminal hydroxide anion (Fig. 2). Fe2(OH)2(dobdc) is likely 

to be formed via a fleeting iron–oxo intermediate, which rapidly 

undergoes hydrogen-atom abstraction. Mössbauer spectroscopy 

was used to probe the local environment of the iron centers 

in the oxidized material, and is consistent with other high-spin 

haem and non-haem Fe(III) species. Rietveld analysis of powder 

diffraction data collected at 100 K on Fe2(OH)2(dobdc) firmly 

established the presence of a new Fe–O bond at a distance of 

1.92(1) Å, consistent with the bond lengths of previously reported 

octahedral Fe(III)–hydroxide complexes (Fig. 2) [1]. Extended 

X-ray absorption fine structure (EXAFS) analysis and periodic 

DFT calculations provided bond lengths that are consistent with 

those obtained from the diffraction data. Surprisingly, the Fe(III)–

hydroxide species is capable of activating weak C–H bonds. When 

the partially oxidized sample Fe2(OH)0.6(dobdc) was exposed to 

1,4-cyclohexadiene at room temperature, benzene was produced 

as the sole product in quantitative yield. In the process, the 

framework converted entirely back to Fe(II), as determined by 

Mössbauer spectroscopy. Such reactivity is rare, but not unprecedented, for Fe(III)–hydroxide compounds. However, the oxidizing 

power of Fe2(OH)2(dobdc) and Fe2(OH)0.6(dobdc) is limited, and 

no reaction was observed with less-activated C–H bonds.

As the isolation of an Fe(III)–hydroxide product from a reaction 

that employs a two-electron oxidant strongly suggests the intermediacy of an Fe(IV)–oxo species, we next carried out the oxidation 

in the presence of a hydrocarbon substrate that contained stronger 

C–H bonds, specifically ethane, hoping to intercept the oxo species 

before its decay. Indeed, flowing an N2O:ethane:Ar mixture 

(10:25:65) over the framework at 75 °C led to the formation of 

various ethane-derived oxygenates, which included ethanol, acetaldehyde, diethyl ether and other ether oligomers. We hypothesized 

that the complex mixture of products was related to the close 

proximity of reactive iron centers, which are 8.13(2) Å and 6.84(1) 

Å apart across and along a channel, respectively. To avoid oligomerization and overoxidation, a mixed-metal MOF, Fe0.1Mg1.9(dobdc), 

in which the Fe(II) sites are diluted with redox-inactive magnesium(II)

centers, was synthesized. Although determining the exact distribution of metal centers in heterometallic MOFs is challenging, 

the unit-cell parameters of Fe0.1Mg1.9(dobdc) are between those 

of Fe2(dobdc) and Mg2(dobdc), which suggests the formation of 

a solid solution rather than a mixture of two separate phases. 

Exposure of Fe0.1Mg1.9(dobdc) to N2O and ethane under the same 

flow-through conditions yielded the exclusive formation of ethanol 

and acetaldehyde in a 10:1 ratio, albeit in low yield; 60 % with 

respect to iron (Fig. 3). 

Although spectroscopic and theoretical studies have long attributed 

the reactivity of non-haem enzymatic and synthetic Fe(IV)–oxo 

complexes to a quintet spin state, only a handful of mononuclear 

high-spin Fe(IV)–oxo species have been characterized, and all 

but one exhibit a trigonal bipyramidal coordination geometry. 

In these systems, the oxo moiety is either extremely unstable 

([Fe(O)(H2O)5]

2+, for example, has a half-life of roughly ten seconds) 

or inaccessible to substrates because of bulky ligand scaffolds, 

which lead to sluggish reactivity. However, the Fe2(dobdc) framework features sterically accessible, site-isolated metal centers 

entrenched in a weak-field ligand environment. Utilizing these two 

properties, it is possible not only to generate such a species, albeit 

fleetingly, but also to direct it towards the facile activation of one 

of the strongest C–H bonds known. With this, Fe2(dobdc) has now 

been shown to stabilize iron–superoxo, –peroxo, –hydroxo and –oxo 

intermediates, which highlights the promise of MOFs both as catalysts and as scaffolds for interrogating reactive metal species [1,2].

References 

[1] D. J. Xiao et al., Nature Chemistry 6, 590 (2014).

[2] E. D. Bloch et al., J. Am. Chem. Soc. 133, 14814 (2011).

FIGURE 2: (Left) Reaction scheme for the preparation of Fe2(OH)2(dobdc) 

from Fe2(dobdc). (Right) The structure of Fe2(OH)2(dobdc) obtained from 

powder diffraction data (100 K). The Fe–OH bond distance of 1.92(1) Å 

is consistent with reported Fe(III)–OH compounds. Orange, red and blue 

spheres represent Fe, O and H, respectively. 

FIGURE 3: Heating of N2O-bound Fe0.1Mg1.9(dobdc) (1) results in the formation 

of a transient high-spin Fe(IV)–oxo species (2), which can react with the 

strong ethane C–H bonds converting it to ethanol (3). Orange, Fe; green, 

Mg; grey, C; dark blue, N; red, O. 

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 19CHEMICAL PHYSICS
Dynamic origin of the anomalous odd-even glass 

transition temperature in an ionic glass

K. Yang,1,2 M. Tyagi,3,4 J. S. Moore,1,2,5 Y. Zhang1,2,6

Odd-even effects are the non-monotonic dependency of 

physical properties on molecular odd-even structural units. 

These effects are widely observed in homologous series of 

crystalline materials with the most well known example being 

the n-alkane series, in which even-membered species have a 

higher melting point (Tm) than odd-membered ones. In general, 

packing effects are used to explain this alternating trend in 

crystalline materials. However, the lack of periodic packing makes 

the odd-even effect unexpected for amorphous materials. We 

have recently found that the odd-even effect also exists in the 

fully amorphous state in a homologous series of network-forming ionic glasses (IGs) where organic multivalent cations and 

anions are connected primarily by electrostatic interactions [1]. 

To understand the phenomenon’s molecular origin, we studied 

the physical and dynamic properties a homologous series of IGs.

Organic molecular glasses are a class of organic molecules that 

do not crystallize readily upon cooling [2]. Structural features can 

be introduced to frustrate crystallization in these materials such 

as including nonpolar molecules and introducing conformers. 

Additionally, among ionic liquids, we can choose from a library 

of ionic interactions in terms of types and strength. By combining 

the design principles of these two types of materials, we 

construct a new kind of material that we call a network-forming 

ionic glass. These glasses include structural frustration from 

alkyl side chains (existence of conformers) and a variety of ionic 

interactions. Organic multivalent cations and anions are paired 

to form a network that possesses reversibility and tunability.

Network-forming IGs were synthesized using diammonium cations 

and citrate anions (Fig. 1). These materials were prepared by 

reacting an α,ω-dibromoalkane with a trialkylamine. The bromide 

counter anion was then replaced with hydroxide using an anion 

exchange column. In situ reaction with citric acid (or other polyacids) produced the desired products and water. We name the series 

of IGs with the form IG A-B where A is the backbone spacer length 

and B is the side chain length (Fig. 1). The amorphous nature of 

IGs was determined by X-ray diffraction (XRD) and differential 

scanning calorimetry (DSC). By changing the side chain length, 

B, the material can be tuned from semi-crystalline to amorphous 

glass. Increasing the side chain length decreases the glass transition 

temperature. Both electrostatic and van der Waals forces influence 

the phase behavior of ionic glasses. Since the electrostatic force 

is inversely proportional to the square of the separation distance, 

increasing the length of side chains enhances the steric hindrance 

between positive and negative charges. As a result, even though 

the van der Waals forces between segments may increase, the 

glass transition temperature drops due to weaker electrostatic 

interactions. In this way, we can fine-tune the ionic interaction 

strength by tailoring the structure of the building blocks.

The glass transition temperatures of various IGs were measured 

using two independent methods: direct measurement by DSC and 

the crossover point of the storage modulus (G’) and loss modulus 

(G’’) under dynamic loading (1 Hz) by rheology. Investigating the 

dependence of Tg on spacer length, the overall trend exhibits a 

1 Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801

2 Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801

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

4 University of Maryland, College Park, MD 20742

5 Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801

6 Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801

FIGURE 1: Chemical formula and simplified 2-D schematic depiction of 

interconnected network-forming ionic glass (side chains in cations are 

not shown).

20 NIST CENTER FOR NEUTRON RESEARCH CHEMICAL PHYSICS
peaked shape (Fig. 2a). The drop in Tg for long spacer lengths is 

explained by the competition between the electrostatic and van 

der Waals forces. An unexpected odd-even effect was observed 

in the spacer length study. IGs with an even number of methylene 

groups consistently have higher Tg than the odd-numbered IGs. 

The alternation amplitude decreases with longer chains, which is 

similar to n-alkanes and their derivates. For spacer length A > 9, 

the odd-even effect was not observed, suggesting the effect 

from weaker ionic interaction per molecular volume becomes 

more prominent. 

To understand the odd-even phenomenon, we measured the 

atomistic dynamics of IGs using incoherent elastic neutron 

scattering (IENS). IENS probes the effective Debye-Waller factor, 

exp[–(〈r2〉 Q2 /6)], averaged over a nano-second time resolution window, which directly yields the hydrogen mean-squared 

displacement (MSD). For our IG system, most of the hydrogen 

atoms are in the cations, so the MSD reflects the cation behavior. 

Three samples (IG 4-4, IG 5-4 and IG 5-6) were chosen in order 

to decouple the contributions to the MSD from the side chains 

and backbone. As shown in Fig. 2b, the MSD as a function of 

temperature can be divided into three regimes: (i) below 100 K, 

MSD shows pure harmonic behavior, almost all relaxational 

degrees of freedom freeze; (ii) From 100 K to 250 K, anharmonic 

motions start contributing. IG 4-4 and IG 5-4 with the same side 

chain length show similar temperature dependence, while IG 5-6 

with longer hexyl side chain exhibits slower motions. This contrast 

suggests that the motion of the IG alkyl side chain dominates in 

this temperature range. In comparison, the backbone is largely 

immobile in this regime as the ionic cross-links behave like anchors 

and restrict the backbone diffusional movement; (iii) above 250 K, 

which is close to the glass transition temperature, the hydrogen 

MSD increases dramatically. IG 5-4 and IG 5-6 with the same 

backbone length behave almost identically while IG 4-4 moves 

much slower. Therefore we can reasonably conclude that in this 

temperature range, the backbone spacer rather than the side 

chain determines the nanosecond molecular motions of IG.

Comparing IG 4-4 and IG 5-4, which have the same length 

of side chain but different number of spacer groups, the main 

difference of their MSD lies in regime (iii) (T > Tg), where IG 4-4 

molecules exhibit considerably slower motions compared to IG 

5-4. This measurement of the molecular mobility explains why IG 

4-4 has a higher Tg than its odd membered counterparts. Indeed, 

the mobility of the molecules is influenced by their structural 

symmetry, central symmetry for even membered IG and mirror 

symmetry for odd membered IG, which ultimately determines the 

configurational entropy of the system and thus affects the glass 

transition temperature. Another interesting feature of the MSD 

plot is that all three curves seem to have a common crossover 

point around 300 K, which is under current investigation.

This organic ionic glass system, with all its versatility, is a model 

system for the study of glasses and liquids. We have discovered 

an intriguing dynamic-related odd-even effect in the amorphous 

state. Measurements of mean squared displacement (MSD) reveal 

the discrete mobility of the side chain and backbone at different 

temperatures. Comparison of odd and even membered MSD 

plots shows the effect is associated with differences in molecular 

mobility. The understanding of such structure-dynamics-property 

relationships can provide guiding principles for the design and 

construction of next-generation adaptive and self-responding 

molecular ionic materials.

References

[1] K. Yang, M. Tyagi, J. S. Moore, Y. Zhang, J. Am. Chem. 

Soc. 136, 1268 (2014).

[2] Y. Shirota and H. Kageyama, Chem. Rev. 107, 953 (2007).

FIGURE 2: (a) Odd-even dependence of the glass transition temperatures 

(determined by both rheology and DSC) of IGs by varying spacer alkyl chain 

length (IG A-3); (b) Nanosecond hydrogen mean squared displacement 

(MSD) of three selective IGs extracted from elastic incoherent neutron 

scattering experiments. The glass transition temperatures in panel (b) are 

determined by DSC.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 21CHEMICAL PHYSICS
TiAu: the first itinerant antiferromagnet 

with no magnetic elements

E. Svanidze,1 J. K. Wang,1 T. Besara,2 L. Liu,3 Q. Huang,4 T. Siegrist,2 B. Frandsen,3 J. W. Lynn,4

A. H. Nevidomskyy,1 M. B. Gamza,5,6 M. C. Aronson,5,7 Y. J. Uemura3 and E. Morosan1

T

he theoretical description of magnetic materials has been a 

challenge since the inception of quantum mechanics, with 

Heisenberg’s perturbation theory to describe magnetic 

insulators and the Slater/Stoner description of metallic magnets. 

The distinction for these two types depends on whether the 

unpaired (“magnetic”) electrons reside on a particular ion, or 

whether they form a polarized band that crosses the Fermi 

energy and are thus itinerant. A vast number of local-moment 

materials are known and very well described theoretically, while 

the description of highly correlated itinerant electron systems 

such as cuprate and iron-based superconductors systems 

remains a central challenge of condensed matter physics. One 

particularly important class of itinerant electron systems is 

where the constituents are nominally non-magnetic, meaning 

that the atoms generally do not develop a local moment. Such 

materials greatly simplify the theoretical considerations, but 

are very rare, with the only two known ferromagnetic systems 

being ZrZn2 [1] and Sc3In [2]. Here we present the magnetic 

properties of TiAu, which we find is the first example of an 

itinerant electron antiferromagnet material with no magnetic 

constituents. A complete theory of magnetism that unifies the 

itinerant and local moment regimes remains elusive, mainly 

due to the limited number of known simple itinerant magnetic 

systems, and it is anticipated that this new system will provide 

important theoretical guidance. 

The first clear evidence for an antiferromagnetic ground state in 

TiAu is the identical zero-field cooled and field-cooled cusp in the 

temperature-dependent magnetic susceptibility M(T)/H around 

36 K, shown in Fig. 1 (left axis). This behavior is analogous to the 

phase transition behavior generally observed for local-moment 

antiferromagnets. Upon warming above the Néel temperature, 

the inverse susceptibility H/(M − M0) (right axis, Fig. 1) is linear in 

temperature over a very large range, up to 800 K [3]. Such CurieWeiss-like temperature dependence of H/M(T) has been long 

considered the hallmark of local moment magnetism, until the 

identical behavior was observed in the weak itinerant ferromagnets ZrZn2 and Sc3In. While self-consistent renormalization theory 

has gone a long way to integrating the local and itinerant pictures 

of ferromagnetism [4], no existing theory accounts for an antiferromagnetic ground state if neither of the constituents is magnetic.

Distinguishing between local and itinerant moment magnetism 

is inherently difficult, especially in the nearly unexplored realm 

of itinerant antiferromagnets. It is therefore striking that in TiAu, 

abundant evidence points towards its itinerant magnetic character. 

The fact that the peak in the specific heat is not as strong as the 

local moment prediction is one such argument, with another 

being the very small magnetic entropy Sm associated with the 

transition, amounting to only ≈ 3 % of that expected (Rln2). 

Despite the remarkably large paramagnetic moment μPM ≃ 0.8 μB, 

the maximum measured magnetization up to 7 T is only 0.01 μB, 

with no saturation observed in the field-dependent data M(H). 

The small magnetic moment in the ordered state, as discussed 

below, compared to the paramagnetic moment, is another 

signature of itinerant magnetism.

1 Rice University, Houston, TX 77005

2 National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32306

3 Columbia University, New York, NY 10027

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

5 Brookhaven National Laboratory, Upton, NY 11973

6 Department of Physics, Royal Holloway, University of London, Egham, TW20 0EX, UK

7 Stony Brook University, Stony Brook, NY 11794

FIGURE 1: Left axis. Zero-field cooled magnetic susceptibility as a function 

of temperature for an applied field of μ0H = 0.1 T. Right axis. Inverse susceptibility H/M along with a Curie-Weiss-like fit (solid line), with θ ≈ - 37 K. 

Inset: the crystal structure of TiAu with Ti (small) and Au (large) atoms. 

(1 emu = 10 A/cm2).

22 NIST CENTER FOR NEUTRON RESEARCH CONDENSED MATTER
To investigate the nature of the ordered magnetism, both neutron 

diffraction and muon spin relaxation data were measured. 

The muon spin relaxation technique provides a microscopic probe 

that determines the local magnetic fields throughout the inside 

of the material. The measurements on TiAu unambiguously 

show that essentially the whole volume of the sample orders 

magnetically, as shown in Fig. 2a. The muon spin relaxation data 

also indicate a very small ordered moment in TiAu, which is also 

confirmed by neutron diffraction measurements. High intensity 

neutron diffraction patterns were obtained both below (T = 2 K) 

and above (T = 60 K) the magnetic ordering temperature on 

BT-7 using the position-sensitive detector. These data reveal a 

magnetic peak that can be indexed as (0,π/b,0) (inset of Fig. 2(b)), 

indicating that commensurate long range magnetic order has 

developed. The ground state ordered moment is estimated to be 

≈ 0.1 μB, and such a small moment is consistent with expectations 

for an itinerant electron system. The temperature dependence 

of the integrated intensity of the magnetic peak is shown in 

Fig. 2b. The solid curve is a simple mean-field fit to determine an 

ordering temperature of 36(2) K, in excellent agreement with the 

susceptibility, specific heat, and muon spin relaxation data. The 

neutron data therefore demonstrate that the magnetic order is 

associated with the TiAu lattice, which together with the muon 

data that the magnetic order exists in the entire sample, rules out 

any extrinsic origins for the magnetism such as an impurity phase 

or grain-boundary/surface effects. Thus the magnetic order is an 

intrinsic property of TiAu.

Overall our data convincingly show that TiAu is the first itinerant 

antiferromagnet with no magnetic constituents, analogous to 

the only two itinerant ferromagnets Sc3In and ZrZn2. This new 

itinerant antiferromagnet challenges the currently limited understanding of weak itinerant antiferromagnetism while providing 

long sought-after insights into the effects of spin fluctuations in 

itinerant electron systems. The discovery of this itinerant electron 

antiferromagnet opens a promising avenue for developing a 

unified theory of magnetism that includes both local and itinerant 

electron systems and the complex magnetism that straddles 

these regimes.

References

[1] B. T. Matthias, R. M. Bozorth, Phys. Rev. 109, 604 (1958).

[2] B. T. Matthias, A. M. Clogston, H. J. Williams, E. Corenzwit, 

R. C. Sherwood, Phys. Rev. Lett. 7, 7 (1961).

[3] E. Svanidze et al., in preparation (2014).

[4] T. Moriya, Spin Fluctuations in Itinerant Electron Magnetism, 

Springer - Verlag, Berlin (1985).

FIGURE 2: (a) Magnetic volume fraction, extracted from muon spin relaxation 

data, as a function of temperature, showing that the entire sample orders 

magnetically. (b) Neutron diffraction data of the integrated intensity of the 

TiAu magnetic Bragg peak as a function of temperature. The solid curve 

is a mean field fit to the powder data to obtain an ordering temperature of 

36 K, in excellent agreement with the susceptibility, specific heat, and muon 

data. Inset: The (0, π/b, 0) magnetic Bragg peak fit with a Gaussian (red line).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 23CONDENSED MATTER
The fluctuating magnetism of triangular 

molecules on a triangular lattice

M. Mourigal,1 W. T. Fuhrman,1 J. P. Sheckelton,1,2 A. Wartelle,1,3 J. A. Rodriguez-Rivera,4,5 D. L. Abernathy,6

T. M. McQueen,1,2 and C. L. Broholm1,4,6

Measured along any direction, the magnetic moment 

of an electron takes on one of two quantized values 

(±μB). Correspondingly, the magnetic moments of a 

pair of electrons can be perpetually antiparallel in the so-called 

“singlet” state with no net moment, or they can conspire to 

form a twice-larger moment. In a compass needle or refrigerator 

magnet, a very large number of electrons combine in the latter 

fashion forming a classical magnetic moment. It is natural to ask 

whether a singlet-dominated state of matter is possible where 

the quantized nature of the electron transcends the atomic scale? 

In a seminal paper published forty years ago, Nobel Laureate 

P.W. Anderson suggested this might occur for electrons on a 

triangular lattice [1]. Now an experiment on the newly enhanced 

MACS spectrometer offers evidence of singlet formation among 

electrons confined to triangular molecules on a triangular lattice. 

The curious “doubly triangular” structure of LiZn2Mo3O8 is shown 

in Fig. 1a [2]. Susceptibility measurements show an intriguing transition from a high temperature regime (T > 100 K) with one active 

spin per triangular Mo3O13 molecule to a low temperature regime 

with one electron spin per three molecules. This loss of moments 

already indicates some sort of quantum singlet formation. The 

absence of conventional magnetic ordering down to T = 0.1 K 

is a further indication of an anomalous electronic state. 

While extending the magnetic orbital from an atom to a molecule 

may be key to realizing resonating valence bonds (singlets) in 

LiZn2Mo3O8, an unfortunate consequence is that magnetic 

neutron scattering is weak and confined to wave vector transfer 

below 1 Å-1 (Fig. 1b). Nonetheless, the high efficiency MACS spectrometer detected a broad, diffusive form of magnetic scattering 

from a powder sample of LiZn2Mo3O8 (Fig. 2a). Conventional 

magnetism is excluded, as the momentum dependence of the data 

(open symbols, Fig. 2c) is broad at energy transfers far less than 

the Curie-Weiss temperature extracted from high temperature 

susceptibility data (ΘCW = -339(12) K [3,4]). Instead we compare 

the data to what would be expected for a singlet-dominated state 

of matter where electron spins fluctuate but remain antiparallel. 

The solid and dashed black lines in Fig. 2c show expectations for 

nearest and next nearest neighbor singlets, respectively, neither 

of which are consistent with the data. A superposition of the two 

(solid blue line in Fig. 2c), however, describes the data well. This 

is a further break with semi classical descriptions of magnetism in 

LiZn2Mo3O8, implying that a ground state with a static or dynamic 

configuration of singlets is formed between electrons confined to 

Mo3O8 molecules.

The zero-field neutron data indicate a continuous and gapless 

spectrum of excitations associated with breaking singlets (open 

1 Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218

2 Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218

3 École Normale Supérieure de Lyon, Université de Lyon, 46 Allée d’Italie, 69364 Lyon Cedex 07, France

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

5 University of Maryland, College Park, MD 20742

6 Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831

FIGURE 1: (a) The extended unpaired electron density associated with 

the triangular lattice of Mo3O13 molecules in LiZn2Mo3O8. (b) The square 

magnetic form factor of Mo3O13 compared to that of Cu2+. Magnetic neutron 

scattering from LiZn2Mo3O8 is complicated because the form factor confines 

the signal to wave vector transfer below 1 Å-1.

24 NIST CENTER FOR NEUTRON RESEARCH CONDENSED MATTER
symbols, Fig. 2d). This cannot be the result of a static, periodic 

arrangement of singlets on the triangular lattice. Applying a 

magnetic field on the other hand, induces a resonance in the 

spectrum of neutron scattering (Fig. 2b and filled symbols, 

Fig. 2d), the wave vector dependence of which shows it to be 

associated with individual magnetized Mo3O13 molecules (red line 

in Fig. 2c). The data clearly identify LiZn2Mo3O8 as a quantum 

dominated magnet but leave several questions unanswered: 

(1) Why do 2/3 of the spins all but vanish from view at low 

temperatures? Absolute normalization of the MACS data show 

the low energy scattering is associated with 1/3 of the Mo3O8

molecules. A higher energy experiment using ARCS at the SNS 

showed the remaining magnetic scattering must be distributed 

through a broad range of energies. This is consistent with 

susceptibility data and the apparent absence of translational 

symmetry breaking. (2) How is it possible for a gapless excitation 

spectrum to be associated with short-range singlet formation? 

The energy to convert an isolated pair of electronic magnetic 

moments from the singlet configuration to the magnetic 

configuration equals a finite antiferromagnetic exchange 

constant. Therefore a gap in the excitation spectrum is expected 

for a static short-range singlet configuration. A satisfactory 

answer to these questions may be found if the configuration of 

singlets itself undergoes quantum fluctuations as envisioned in 

Anderson’s resonating valence bond state. Possible factors that 

have been proposed to drive the exotic magnetism of LiZn2Mo3O8

are molecular distortions or rotations that influence inter-site 

interactions [5] and delocalization of electrons beyond their host 

Mo3O13 molecules described by a Hubbard model on a distorted 

kagome lattice [6]. Neutron scattering from single crystalline 

samples will be required to distinguish such scenarios and to 

exclude a disorder dominated random singlet state. For now the 

important experimental finding is that singlet dominated quantum 

magnetism is possible on the triangular lattice when electrons 

occupy molecular rather than atomic orbitals.

References

[1] P.W. Anderson, Mater. Res. Bull. 8, 153 (1973).

[2] J. P. Sheckelton, J. R. Neilson, D. G. Soltan, T. M. McQueen, 

Nat. Mater. 11, 493 (2012).

[3] M. Mourigal, W. T. Fuhrman, J. P. Sheckelton, A. Wartelle, 

J. A. Rodriguez-Rivera, D. L. Abernathy, T. M. McQueen, 

C. Broholm, Phys. Rev. Lett. 112, 027202 (2014).

[4] J. P. Sheckelton, F. R. Foronda, LiDong Pan, C. Moir, R. D. 

McDonald, T. Lancaster, P. J. Baker, N. P. Armitage, T. Imai, 

S. J. Blundell, T. M. McQueen, Phys. Rev. B 89, 064407 (2014).

[5] R. Flint, P. A. Lee, Phys. Rev. Lett. 111, 217201 (2013).

[6] G. Chen, H.-Y. Kee, Y. B. Kim, arXiv:1408.1963 (2014).

FIGURE 2: Color map of the magnetic neutron scattering intensity from 

LiZn2Mo3O8 in (a) zero magnetic field and (b) 9 T magnetic field. The substantial field effect identified this scattering as magnetic. (c) Shows the wave 

vector dependence of the scattering integrated over the indicated energy 

ranges. The zero field data are consistent with a magnetic ground state 

consisting of a superposition (solid blue line) of quantum singlets between 

nearest (solid black line) and second nearest (dashed black line) neighboring 

Mo3O13 molecules. The field induced resonance carries the wave vector 

dependence of the theoretical form factor of the Mo3O13 molecule (solid red 

line). (d) The spectrum of magnetic neutron scattering from LiZn2Mo3O8 in 

zero field (open symbols) and 9 T (closed symbols) showing the transition 

from a continuum of scattering to a well defined resonance associated with 

precession of the molecular magnetization. 

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 25CONDENSED MATTER
Giant charge fluctuations with Se-height 

and Fe-vacancy formation in MxFe2−ySe2

X. Luo,S. Ög ̆ üt,1 and T. Yildirim2, 3

S

uperconductivity was recently discovered in alkali-metal 

doped iron-selenide systems MxFeySe2 at Tc’s up to 32 K [1,2]. 

One of the most important questions about this class of 

materials is related to the similarities and differences between 

the iron selenide and pnictide systems. In this work, we present 

important results from state-of-the-art first principles calculations that address this issue. We show that there is an intimate 

relationship between the Se height and the spin configuration 

of the underlying Fe-square in MxFe2-y Se2, where M denotes 

an alkali metal. A displacement of the Se atom by an amount as 

small as 0.2 Å is enough to change the amount of charge in the 

Fe-plane by as much as 0.7 electrons per Fe. The height of the Se 

atom above the Fe-square increases as the number of ferromagnetic Fe-Fe bonds increases, yielding an expansion of 2 Å in the 

c-axis for the fully ferromagnetic spin configuration. This suggests 

the presence of a giant magneto-elastic coupling in this system. 

We show that the formation of Fe vacancies is energetically 

favorable, and that their presence changes the ground state from 

double-stripe to block-antiferromagnetic ordering. The formation 

of K vacancies is found to be energetically unfavorable. 

We first consider the ideal 122 MFe2Se2 structure with 

non-magnetic (NM) as well as the following four magnetic 

configurations shown in Fig. 1: Anti-ferromagnetic stripe (AFs), 

anti-ferromagnetic checkerboard (AFc), anti-ferromagnetic double 

stripe (AFd), and ferromagnetic (FE) phases. We then consider 

the experimentally observed √5 x √5 supercell as determined by 

neutron scattering with and without Fe vacancies (Fig. 1e - 1f). 

Our first principles calculations are performed with a plane wave 

basis set within the framework of density functional theory using 

the Perdew-Burke Ernzerhof exchange-correlation functional as 

implemented in the VASP package.

To demonstrate the dependence of total energy and magnetization 

on the Se-height zSe, we performed self-consistent calculations 

with different zSe values in a fixed cell. Fig. 2 shows the results for 

five different spin configurations in the optimal AFs cell of KFe2Se2

and the FE-cell of NaFe2Se2. For the case of K (Fig. 2, left panel), 

when zSe, is larger than 1.4 Å, the Fe magnetic moment increases 

linearly with zSe. Once zSe is below 1.4 Å, the magnetic moment 

drops quickly as zSe decreases. The Fe atoms in the FE and AFs 

phase lose their magnetization when zSe is smaller than 1.25 Å. 

We note that the energetic ordering of the five phases (with 

1 University of Illinois at Chicago, Chicago, IL 60607

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

3 University of Pennsylvania, Philadelphia, PA 19104

respect to magnetic configuration) depends on zSe. In KFe2Se2, 

AFs competes with AFd to become the ground state with zSe

controlling the competition. When zSe increases from 1.44 Å to 

1.48 Å, the ground state switches from AFs to AFd. In NaFe2Se2

(Fig. 2, right panel), it is the AFd and FE phases that compete 

FIGURE 1: (a-d) Four different magnetic structures of MFe2Se2. AFs, AFd, 

AFc, FE denote anti-ferromagnetic stripe, anti-ferromagnetic double-stripe, 

anti-ferromagnetic checkerboard, and ferromagnetic spin configurations, 

respectively. (e-f) The optimized structures of the anti-ferro block stripe 

phase within the √5 x √5 cell without (e) and with the Fe-vacancies (f).

26 NIST CENTER FOR NEUTRON RESEARCH CONDENSED MATTER
for the ground state: When zSe is less than 1.6 Å, the AFd spin 

configuration is the ground state. However, with a small increase in 

zSe from 1.6 Å to 1.65 Å, the ground state changes to the FE spin 

configuration. Hence, for both K and Na, the ground state spin 

configuration is very sensitive to the height of the Se ion.

Recent neutron experiments indicate [3] that these systems 

possess significant Fe vacancies, which are ordered in a √5 x √5 

cell as shown in Fig 1e - 1f. Hence, it is important to understand 

the energetics of Fe and K vacancy formation in these systems. 

We calculated the Fe and K vacancy formation energies in a 

√5 x √5 cell for both the AFd and NM phases. We considered 

three vacancy structures for the AFb phase: KFe1.6Se2 with only 

Fe vacancies, K0.8Fe2Se2 with only K vacancies, and K0.8Fe1.6Se2

with both Fe and K vacancies, and obtained the Ev values of 

Next, we show that the charge distribution in Fe-selenides is also 

very sensitive to the Se-height. In order to demonstrate this, we 

first calculate the charge density as a function of the coordinate z

along the c-axis, ρ(z), by averaging the full charge density ρ(x,y,z) 

in the x-y plane. We then plot the change Δρ(z) in the averaged 

charge density as Se ions are shifted along the z-direction by 

a small amount. Fig. 3 shows such a charge density difference 

plot for a Se-displacement of 0.2 Å. We see that there is a huge 

charge transfer from the Se-Fe-Se region to the Se-K-Se region 

upon a small Se-displacement. On average, the Se-Fe-Se region 

loses about 0.7 electrons per Fe with a 0.2 Å increase in the 

Se-height, suggesting that Fe-Se and Se-Se hybridizations are 

strongly coupled.

-0.55 eV, 0.90 eV, and 1.24 eV, respectively. The negative energy 

for the structure with the Fe vacancy only indicates that Fe vacancies are energetically favorable. However, the large positive defect 

energies for K vacancies (with and without the Fe vacancies) 

suggest that K-vacancy formation is not energetically favorable. 

Hence, according to these results, the samples should always 

have Fe vacancies but the presence of K vacancies would depend 

on how fast the samples are quenched during the synthesis and 

may show variance from sample to sample.

In conclusion, we have examined the coupling of the Se-height to 

the spin configuration in the underlying Fe-squares in MxFe2Se2. 

We have shown that this coupling, while rather local, is so strong 

that a displacement of the Se atom by as little as 0.03 Å is enough 

to change the magnetic configuration of the Fe-square. This Se 

displacement works like a charge-valve; a displacement as small as 

0.2 Å can transfer about 0.7 electrons per Fe from the Se-Fe-Se 

region to the Se-K-Se region. We believe that these results are 

likely to provide new research directions for experimentalists 

such as the possible observation of a collapsed non-magnetic 

phase under pressure when small alkali metals are doped into 

the Fe-selenides.

References

[1] J. Guo et al., Phys. Rev. B 82, 180520 (2010). 

[2] X. Luo, S. Ög ̆ üt, T. Yildirim, Phys. Rev. B 89, 054519 (2014).

[3] J. Zhao, H. Cao, E. Bourret-Courchesne, D. –H. Lee, R. J. Birgeneau, 

Phys. Rev. Lett. 109, 267003 (2012).

FIGURE 2: The dependence of Fe magnetic moment (top) and the total 

energy (bottom) on the z-position of Se (zSe) in the optimized AFs-cell of 

KFe2Se2 (left) and the FE-cell of NaFe2Se2 (right).

FIGURE 3: The plot of the charge density difference averaged over the x-y

plane as the Se atoms zSe are shifted away from the Fe-plane in the AFs 

optimal cell of KFe2Se2. The shaded area indicates the large charge transfer 

of 2.71 e (per four Fe ions) from the Se-Fe-Se region to the Se-K-Se region 

with a small Se-displacement of 0.2 Å. Vertical solid and dashed lines 

shows the Se-position before and after the Se displacement. The solid green 

line shows the averaged charge density difference upon the same 0.2 Å 

Se-displacement for the √5 x √5 cell with Fe-vacancies shown in Fig. 1f.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 27CONDENSED MATTER
Phonon localization drives polar nanoregions 

in a relaxor ferroelectric

M. E. Manley,1 J. W. Lynn,2 D. L. Abernathy,1 E. D. Specht,1 O. Delaire,1 A. R. Bishop,3 R. Sahul,4 and J. D. Budai1

F

or over 50 years it has been known that conventional 

ferroelectrics form long-range polar order upon cooling by 

the gradual slowing (softening) of a zone center transverse 

optic (TO) phonon. Relaxor ferroelectrics, on the other hand, are 

chemically disordered ferroelectrics with technologically useful 

properties that are not well understood. The useful properties 

of relaxor ferroelectrics originate with polar nanoregions (PNRs), 

although there is no agreement on how PNRs form. Possible 

explanations range from analogs with frustration in magnetic 

spin glasses, to short-range chemical order, to the nonlinear 

localization and slowing of phonons at “dopant” sites (intrinsic 

localized modes) [1]. However, none of these models explain the 

size, shape, and distributions of the PNRs, nor do they explain the 

appearance of antiferroelectric nanoregions with zone-edge TO 

phonon displacements. In recent work, using neutron scattering to 

characterize the lattice dynamics of relaxor PMN-30%PT, we have 

discovered a new phonon localization mechanism that explains the 

size and shape of the PNRs as well as zone-edge antiferroelectric 

nanoregions in terms of the coherent trapping of the TO phonons 

by randomly distributed localized resonance modes [2].

Near the Burns temperature (Td) a dispersionless mode forms 

in resonance with the TO phonon with a flat intensity profile, 

indicating a fully localized stationary mode (Fig. 1a). On cooling 

towards the ordering temperature, Tc, however, the intensity of 

the localized phonons becomes peaked at the crossing with the 

TO phonon (Fig. 1b). These localized phonons have a coherence 

length (size) that equals a single TO wavelength at the crossing 

(Fig. 1c), and this size matches the PNRs. Furthermore, near the 

zone edge high-symmetry M point (antiferroelectric), the intensity 

becomes enhanced at a 2nd crossing (Fig. 1d and Fig. 1e). The size 

of the localized modes is set by the wavelength of the TO phonon 

where the TO phonon dispersion surface crosses the resonance 

local mode. This relationship explains the evolution of the size, 

shape, and positions in reciprocal space of the PNR and antiferroelectric nanoregion diffuse scattering patterns in PMN-xPT 

for x = 0 % to 30 % [2]. As described below, these results are 

explained in terms of an Anderson-type localization mechanism, 

where constructive interference of the TO phonons interacting 

with randomly distributed localized resonance modes results in 

the localization of both the ferroelectric and antiferroelectric 

TO phonons. 

To understand these results, it is instructive to first consider the 

apparently paradoxical result that the localized mode becomes 

longer lived (sharper in energy) as it forms resonance crossings 

with the TO phonon [2]. As depicted in Fig. 2a, a localized mode 

in resonance with traveling phonons, in this case the TO phonons, 

is expected to radiate these phonons. The radiation of energy 

through the TO phonons is expected to quickly disperse the 

resonance mode energy, thereby relegating it to a short-lived 

fluctuation rather than a long-lived excitation. As depicted in 

Fig. 2b, however, it is possible to “trap” (localize) the radiating 

phonons between two resonance modes in 1D. The radiating 

phonons constructively interfere to form a standing wave 

1 Oak Ridge National Laboratory, Oak Ridge, TN 37831

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

3 Los Alamos National Laboratory, Los Alamos, NM 87545

4 TRS Technologies, State College, PA 16801

FIGURE 1: Inelastic neutron scattering measurements of phonons in

PMN-30%PT. (a) and (b) are measured along Γ-X at 688 K and 488 K 

using BT7 at NIST. (c) Intensity profile and fits for the indicated local modes. 

At 688 K the mode intensity is flat, which implies well localized. At 488 K the 

profile indicates a coherence length of 2 nm, which matches the wavelength 

at the resonance crossing and the PNR size. (d) and (e) are measured along 

Γ-M at 688 K and 488 K using ARCS at SNS.

28 NIST CENTER FOR NEUTRON RESEARCH CONDENSED MATTER
between the pair while destructively interfering outside of the 

pair, resulting in a long-lived bound state. The problem of how 

radiating phonons become localized in a random 3D distribution 

of resonance modes is, in essence, Anderson localization [3]. The 

reason is illustrated in Fig. 2c: waves emanating from a single 

resonance mode and traveling in equal by opposite directions 

around the same random scattering path constructively interfere 

on returning. Anderson localization is exponential in real space, 

which transforms to Lorentzian in reciprocal space (Fig. 2d), 

and the characteristic length scale, L, is the wavelength of the 

trapped phonon. Invoking the convolution theorem, the localized 

TO phonon is as a q-broadened TO mode centered at the 

crossing and with a coherence length matching the wavelength 

(Fig. 2e). This explains the observed dynamical structure shown 

in Fig. 1b and Fig. 1e. The trapped wavelength of 2 nm matches 

the coherence length of the localized phonon and the size of 

the PNRs. Considering how the trapping wavevector maps 

with direction, Fig. 3a, explains why the anisotropy of the PNR 

diffuse scattering follows the anisotropy of the TO phonon [4]. 

Furthermore, the trapping wavevectors at the zone edge M points, 

Fig. 3b, explains why antiferroelectric nanoregions of distortion 

develop at these points in reciprocal space [5]. This mechanism 

is generic and may apply to other disorder-frustrated ferroic 

materials, where function often originates with nanoregions.

References

[1] R. A. Cowley et al., Adv. Phys. 60, 229 (2011).

[2] M. E. Manley et al., Nature Commun. 5:3683 doi: 10.1038/

ncomms4683 (2014).

[3] A. Lagendijk, B. Tiggelen, D. S. Wiersma, Phys. Today 62, 

24 (2009).

[4] M. Matsuura et al., Phys. Rev. B 74, 144107 (2006).

[5] I. P. Swainson et al., Phys. Rev. B 79, 224301 (2009).

FIGURE 2: Trapping ferroelectric modes with resonance modes. (a) Resonance mode radiating TO phonons. (b) Trapped TO phonon in 1D. (c) Anderson 

localization scheme. (d) Exponential localization transformation. (e) Modifications to the dispersion curves from an Anderson-localized standing TO 

phonon at the resonance wave vector.

FIGURE 3: Trapping wavevectors expected for a single resonance mode 

frequency crossing the dispersion surface of the transverse optic (TO) 

phonon. (a) A comparison of the trapping wavevectors, q0, expected near the 

zone center for PMN-30%PT and PMN. The trapping wavevector loci map 

to the observed diffuse scattering anisotropy [4]. (b) Locations in reciprocal 

space where the 2nd crossing introduces trapping wavevectors near the 

M points. These are the wavevectors where antiferroelectric distortions 

were observed [5].

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 29CONDENSED MATTER
Effect of interfacial octahedral behavior 

in ultrathin manganite films

E. J. Moon,1 P. V. Balachandran,1 B. J. Kirby,2 D. J. Keavney,3 R. J. Sischel-Tissot,1

C. M. Schlepütz,3 E. Karapetrova,3 X. M. Cheng,4 J. M. Rondinelli,1 and S. J. May1

T

ransition metal oxides featuring strongly correlated electrons 

exhibit a host of fascinating and useful properties, such 

as ferromagnetism, ferroelectricity, and superconductivity. 

New and different properties can emerge at an abrupt interface 

between two such materials with differing ground states [1]. 

As such, novel materials featuring electronic and magnetic 

properties not found naturally can be artificially designed through 

precise epitaxial growth of oxide thin film heterostructures. For 

example, it is known that in bulk, altering the rotation angle of 

the constituent BO6 octahedra can stabilize different electronic 

and magnetic phases in ABO3 perovskites. In principle, it should 

therefore be possible to tune the properties of ABO3 thin 

films via interfacing with a material exhibiting an appropriate 

degree of octahedral rotation. In practice however, for such a 

heterostructure it is difficult to distinguish the contributions of 

octahedral coupling from those of epitaxial strain. 

To isolate the role of octahedral rotations, we have studied the 

electronic and magnetic properties of La2/3Sr1/3MnO3 (LSMO) 

films epitaxially grown on different oxide substrates with similar 

lattice parameters, but that either do or do not exhibit octahedral rotation [2]. In bulk, 1/3 doped LSMO is ferromagnetic, 

has an a- a- a- tilt pattern, with a pseudocubic lattice parameter 

apc = 3.873 Å, and a uniform 166.3o B-O-B bond angle. Using 

molecular beam epitaxy, ultra-thin LSMO layers were grown on 

the (001) surface of (LaAlO3)0.3(Sr2AlTaO6)0.7 (i.e. LSAT), the (001) 

surface of NdGaO3 (NGO) and the (110) surface of NGO. LSAT is 

cubic, with apc = 3.868 Å, and lacks octahedral rotations – i.e. it 

exhibits an a0 a0 a0 tilt pattern and a uniform 180o B-O-B bond 

angle. Conversely, NGO is orthorhombic, with apc = 3.862 Å, and 

exhibits significant octahedral rotations – an a- a- c+ tilt pattern 

with an average B-O-B bond angle of 154o. The LSMO / substrate 

interfacial structure is depicted in Fig. 1. In principle, rotations 

of the MnO6 octahedra in LSMO (in pink) should be altered via 

coupling with the LSAT (blue) or NGO (green) substrates. For 

growth on the LSAT substrate, the lack of octahedral rotation 

should lead to larger LSMO bond angles near the substrate 

interface compared to films grown on NGO – an effect that 

could manifest itself in bandwidth related properties such as 

resistivity and magnetization.

X-ray diffraction measurements were performed at beamline 

33-BM-C of the Advanced Photon Source. Fig. 2 shows scans of 

intensity vs. wavevector transfer (Qz) about the pseudocubic LSMO 

(002) peak for films 11 unit cells (u.c.) thick grown on each of the 

three substrates. Pronounced LSMO Bragg peaks are observed 

indicating layered order along the growth axis, while the presence 

1 Drexel University, Philadelphia, PA 19104

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

3 X-ray Sciences Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439

4 Bryn Mawr College, Bryn Mawr, PA 19010

FIGURE 1: Schematic of the LSMO/LSAT and LSMO/NGO heterostructures.

FIGURE 2: X-ray diffraction scans about the LSMO (002) for samples grown 

on (from top) LSAT (001), NGO (001), and NGO (110).

30 NIST CENTER FOR NEUTRON RESEARCH CONDENSED MATTER
of clear Kiesseg fringes indicates good film quality. Most importantly, the LSMO (002) peaks are observed at effectively identical 

values of Qz, indicating that the LSMO growth axis lattice parameters are also the same. This is evidence that the differences in 

substrate are not changing the strain state of the LSMO films, and 

that any observed variations in electronic or magnetic properties 

are attributable to changes in octahedral rotation.

Direct current transport measurements were used to characterize electronic properties of the samples. Fig. 3 shows the 

temperature-dependent resistivity for LSMO films of varying 

thickness grown on the different substrates. As expected, resistivity decreases with increasing thickness, but additionally, for a 

given thickness band, films grown on LSAT consistently exhibit 

the lowest resistivity. This demonstrates that by changing the 

substrate, we are indeed changing the electronic properties of 

the LSMO film.

Such changes in electronic structure make substrate-dependent 

variations in magnetic properties plausible as well. Given the 

interfacial nature of the substrate-dependent effects, it is desirable 

to use a depth-sensitive probe to characterize the magnetization. Thus, polarized beam reflectometry (PNR) measurements 

were performed using the PBR beamline at the NCNR. 18 u.c. 

thick LSMO samples were cooled to 100 K in a magnetic field 

μ0H = 0.5 T applied parallel to the sample plane. The incident 

neutron beam was spin polarized such that the neutron magnetic 

moment was either parallel (+) or anti-parallel (-) to H, and the 

non spin-flip reflectivities R++ and R-- were measured as functions 

of Qz. These data are shown in Fig. 4 (a-c), multiplied by Qz

4 in 

order better simultaneously visualize features at low Qz (where 

the reflected intensity is high) and high Qz (where the reflected 

intensity is orders of magnitude lower). Pronounced spin-dependent oscillations are observed, indicating sensitivity to the nuclear 

and magnetic depth profiles. Model fitting of the data yields the 

profiles shown in Fig. 4(d). 

Starting at the right of Fig. 4(d), we find significant differences in 

the magnetizations of the free LSMO surfaces of the samples. In 

particular, the free surface of the sample grown on NGO (001) has 

a region of suppressed magnetic moment much larger than do 

the other two samples. However, X-ray absorption spectroscopy 

measurements (not shown) suggest that this difference arises from 

increased surface oxidation for the NGO (001) sample, and is likely 

independent of variations due to substrate.

On the other hand, there are features in the magnetic profiles 

that are indeed pertinent to this study. For all three samples, there 

is a region of LSMO approximately 5 u.c. thick at the substrate 

interface with significantly reduced magnetic moment. This 

region does not coincide with a change in the nuclear scattering 

length density profile, indicating that it does not arise from a local 

variation in composition. Instead, we conclude that this magnetic 

suppression corresponds to a region of LSMO with pronounced 

distortions in octahedral rotation in all three samples. Finally (and 

most importantly), the LSMO/LSAT sample exhibits a significantly 

higher maximum magnetic moment than LSMO grown on NGO. 

It would be expected that “straightening out” the LSMO octahedral rotation should lead to increased electronic bandwidth, corresponding to increased conductivity and magnetization. Therefore, 

if our picture of octahedral coupling in Fig. 1 is correct, we would 

expect LSMO grown on LSAT to exhibit lower resistivity and higher 

magnetic moment than LSMO grown on NGO – and indeed that is 

what we observe. 

In conclusion, we have shown pronounced changes in the electronic and magnetic properties of ultrathin LSMO films grown on 

cubic and orthorhombic substrates, despite the same strain state 

imposed by these substrates. This effect is attributed to interfacial 

structural coupling, leading to reduced MnO6 rotations near the 

film / substrate interface in the LSMO / LSAT compared to LSMO / 

NGO. This work demonstrates the functional properties of oxide 

heterostructures can be controlled via interfacial BO6 rotations. 

References

[1] H. Y. Hwang et al., Nat. Mater. 11, 103 (2012).

[2] E. J. Moon et al., Nano Letters 14, 2509 (2014).

FIGURE 3: Resistivity (ρ) for samples of varying thickness.

FIGURE 4: Fitted PNR data for (a) LSMO/LSAT, (b) LSMO/NGO (001), and 

(c) LSMO/NGO (110). (d) Nuclear (dotted line, shown for LSMO/LSAT) and 

magnetic (solid lines) depth profiles determined from the fits in (a-c).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 31CONDENSED MATTER
Comparison of methods for the measurement 

of deformation induced martensite formation

K. S. Raghavan,1 G. Thomas,1 J. Arnold,1 and T. Gnaupel-Herold2

T

he current level of research in sheet metal development 

has delivered materials that exhibit extreme strength 

while retaining significant straining reserve and formability – properties that come at a premium in the automotive 

industry. Transformation induced plasticity is a significant source 

of strengthening in metastable austenitic stainless steels, in 

low carbon TRIP steels, and in third generation quenched and 

partitioned steels. All these steels rely on transformation of 

remaining austenite (face centered cubic iron) into martensites (body centered tetragonal and hexagonal forms of Fe-C-X 

compounds, with X being stabilizing alloy constituents) to 

increase strength level and ductility. Consequently, accurate 

evaluation of phase volume fractions of remaining austenite 

is of considerable interest, both in the context of alloy design 

and in the development of constitutive hardening models.

Several methods have been proposed to study the evolution of 

transformed martensite following straining. The more common 

measurement techniques are based on the ferromagnetic 

properties of α’ and δ martensite: the FERITSCOPE instrument 

uses magnetic induction to determine the ferromagnetic constituents; a SATMAGAN analyzer uses a magnetic force balance 

method based on applying a saturating magnetic field to the 

specimen. Paramagnetic phases cannot be detected directly. 

Specific concerns include the dependence of the magnetic signal 

on specimen geometry, texture, magnetic permeability changes 

of α’ martensite with strain and sensitivity to applied stress.

X-ray diffraction (XRD) methods have also been used extensively 

for phase volume fraction measurement. The principles of diffraction based phases analysis are well established; however, there 

are lingering concerns about the surface limit (interaction volume 

≤ 0.01 mm3), and the influence of crystallographic texture. In 

practice, using multiple reflections for each phase with specimen 

rotation/tilt for better averaging alleviates the effect of texture. In 

recent years neutron diffraction (ND) has emerged as a useful tool 

to study phase volume fractions on sheet metal samples. Some 

benefits of neutron diffraction over XRD include the orders of 

magnitude larger sample interaction volume, and a largely eliminated texture effect through complete orientation averaging.

Here, FERITSCOPE MP-30 measurements are compared with XRD 

and ND on a metastable austenitic stainless grade (UNS S20400 - 

NITRONIC 30) for a wide range of pre-strain conditions resulting 

in different states of preferred orientation (uniaxial tension, cold 

rolling, plane strain tension, balanced biaxial tension), with the 

focus on the functional correlation between the magnetic induction (MI) measurements and the diffraction measurements [1].

This multi-laboratory comparison shown in Fig. 1 is notable 

in several respects. The scatter among diffraction results is 

substantial, and there is no single identifiable reason responsible for the differences. Among the XRD measurements, 

CSM reports the smallest standard deviation (1 %) but it uses 

one sample orientation (< 1 % of orientation space), with 

ε-martensite identified and included. UC and NIST use some 

averaging over sample orientations (coverage of orientations 

space: UC ≈ 2.5 %; NIST-XRD ≈ 45 %) but the equipment 

used cannot resolve ε-martensite diffraction peaks.

Through complete orientation averaging (100 % of orientation 

space), neutron diffraction (ND) provides superior texture averaging and it uses the largest number of peaks in the analysis, with 

interaction volumes of the order of ≈ 100 mm3, which is similar to 

FERITSCOPE. Most notable, however, is the increasing difference 

1 AK Steel Corporation, West Chester, OH 45069

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

FIGURE 1: Comparison of austenite volume fraction by magnetic induction, 

X-ray diffraction and neutron diffraction for specimens deformed in uniaxial 

tension (0 % to 50 % engineering strain) at 4 °C. The accompanying microstructural changes are shown in the micrographs. Light colored regions 

indicate austenite; darker regions are martensites. Legend: University of 

Cincinnati (UC); Colorado School of Mines (CSM); NIST Center for Neutron 

Research (NIST).

32 NIST CENTER FOR NEUTRON RESEARCH ENGINEERING PHYSICS
between diffraction results and MI measurements. This finding 

holds across different deformation paths as shown in Fig. 2 for 

cold rolled samples.

Dependence of deformation mode on the relationships between 

neutron diffraction and magnetic induction is shown in Fig. 4; it is 

apparent that the regression slopes vary substantially with deformation mode. Plane strain and balanced biaxial stretching slopes 

are lower than for uniaxial tension and cold rolling which creates 

concerns in using a single regression slope for converting magnetic 

induction measurements to neutron diffraction estimates in 

different deformation modes. The reasons for the observed 

differences in the relationship between different measurement 

techniques and deformation mode require further investigation 

beyond the scope of this work.

Reference

[1] K. S. Raghavan, G. Thomas, J. Arnold, T. Gnaupel-Herold, 

Proc. of MS&T, Pittsburgh, PA, in press (2014).

Folded into the results shown in Fig. 1 and Fig. 2 is not only the 

evolving texture but also the appearance of the hard-to-detect 

paramagnetic ε-martensite which tops out at a volume fraction 

of 11 % before nearly disappearing by 40 % strain (Fig. 3). The 

appearance of ε-martensite provides a partial answer to the 

question why neutron diffraction yields the lowest estimate 

of austenite content: the estimates from MI and XRD (Fig. 2) 

represent the sum of austenite and ε-martensite while neutron 

diffraction represents austenite only. The reason for the remaining 

difference between MI and diffraction methods cannot be conclusively discussed here; the purpose of this investigation was to 

elucidate the functional relationship between the estimates from 

FERITSCOPE and neutron diffraction. The result is shown in Fig. 4.

FIGURE 2: Comparison of austenite volume fraction measurement with 

magnetic induction, X-ray diffraction and neutron diffraction methods for 

specimens cold rolled (CR) up to 40 % at room temperature. 

FIGURE 3: Phase volume fraction changes based on neutron diffraction 

measurements as a function of strain during isothermal tensile straining 

at 4 °C. One standard deviation is approximately 3 %.

FIGURE 4: Comparison of neutron diffraction measurement with FERITSCOPE magnetic induction to study evolution of strain induced martensite 

in austenitic stainless steel under different strain paths.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 33ENGINEERING PHYSICS
Determining the effective transverse 

coherence of a neutron wave packet

C. F. Majkrzak,1 C. Metting,1,2 B. Maranville,1 J. A. Dura,1 S. Satija,1 T. Udovic,1 and N. F. Berk1,2

T

he goal of this investigation [1] was to determine the effective 

coherent extent of the neutron wave packet transverse to its 

mean propagation vector k, when it is prepared in a typical 

instrument used to study the structure of materials in thin film 

form via specular reflection. There are two principal reasons for 

doing so. One is the fundamental physical interest in the characteristics of a free neutron as a quantum object while the other is of 

a more practical nature, relating to the understanding of how to 

interpret elastic scattering data when the neutron is employed as a 

probe of condensed matter structure on an atomic or nanometer 

scale. Knowing such a basic physical characteristic as the neutron’s 

effective transverse coherence can dictate how to properly analyze 

specular reflectivity data obtained for material film structures 

possessing some amount of in-plane inhomogeneity. We describe 

a means of measuring the effective transverse coherence length 

of the neutron wave packet by specular reflection from a series 

of diffraction gratings of different spacings.

The process of elastic, specular neutron reflection (SNR) 

(momentum transfer Q normal to the film surface) from layered 

film structures can be remarkably well described by plane wave 

solutions of a time-independent, one-dimensional Schrödinger 

wave equation. Nonetheless, it is unphysical, in principle, to 

describe the neutron wave function as a single plane wave 

composed of identical, parallel wave fronts of infinite lateral 

extent. In reality, the wavefronts representing an incident neutron 

are of finite size. Consequently, a theoretical analysis of SNR is 

valid only if the in-plane sample area illuminated by the projection 

of the transverse extent of the wave onto the surface is sufficient 

to effectively average over any existing in-plane inhomogeneities 

in scattering length density (SLD). Otherwise, an area-weighted, 

incoherent sum of independent reflectivities would be measured, 

necessitating a modified, more complicated analysis and 

interpretation of the data.

For neutrons produced at a source that is both temporally and 

spatially incoherent, the remark by Dirac [2] that “. . . a photon only 

interferes with itself . . .” applies in this case to neutrons as well. 

To describe the wave-like behavior of a localized quantum object 

such as the neutron, the concept of a wave packet was originally 

conceived as a mathematical representation consisting of a continuous, coherent superposition of plane-wave momentum eigenstates. The wave packet construction effectively creates a probability distribution for finding a neutron in a finite, localized region 

of ordinary space while at the same time preserving the essential 

wave property of coherence. Such a picture is consistent with, and 

is a natural consequence of, the Heisenberg uncertainty principle.

Now the very same optical elements in an experimental set-up, 

i.e., moderator, guides, monochromating crystal, and slits which 

impart a particular form and size to the neutron wave packet also 

define, at the same time, the incoherent distribution of mean 

wavevector values corresponding to each of the individual neutron 

wave packets that compose a beam and associated resolution. 

By analyzing the shape of the specular reflection curve for each 

of a set of uniform, rectangular gratings of incrementally differing 

periods – particularly in the region about the characteristic critical Q

below which total external neutron reflection occurs – the effective 

transverse coherence length of the neutron wave packet can be 

determined within well-defined limits, almost independently of 

the angular divergence and wavelength spread of the beam.

In the experiments reported here, the conventional roles of the 

neutron and grating are interchanged – we use the gratings 

of “known” physical characteristics to probe an “unknown” 

wave property of the neutron. A comprehensive set of specular 

reflectivity measurements were performed for various neutron 

monochromators and sources (pyrolytic graphite, perfect single 

crystal silicon, vanadium) and different beam angular divergences 

and wavelength bandwidths. (The results of the specular measurements were corroborated by conventional non-specular, grating 

reflection width analysis.)

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

2 University of Maryland, College Park, MD 20742

FIGURE 1: Grating stripes perpendicular to the scattering plane defined 

by incident and reflected nominal wavevectors. (In the actual instrumental 

configuration, the scattering plane is horizontal.)

34 NIST CENTER FOR NEUTRON RESEARCH NEUTRON PHYSICS
The basic orientation of the grating structure used in the specular 

reflectivity measurements is shown in Fig. 1. If in-plane variations in 

SLD are present but of sufficiently small magnitude and/or spatial 

extent that the specular analysis remains a good approximation, 

then the effective SLD depth profile corresponds to the in-plane 

average SLD. A typical specular reflectivity model curve for a film 

(approximately 1000 Angstroms thick) composed of equal areas 

of two different constant SLDs (for Ni and Si on a semi-infinite 

substrate of Si) – and for which the dimensions of the in-plane 

areas of each of the two materials are sufficiently smaller than 

the projected length of the transverse dimension of the neutron 

wave packet (as depicted in the inset) – is shown in Fig. 2(a). In this 

case a single critical Q is observed which is related to a SLD that 

is the average of that for the two materials. In Fig. 2(b) is another 

real-space structure which has, again, equal net areas of the 

same pair of different constant SLDs but where now the areas of 

each material are divided into constituent sub-areas which have 

dimensions large enough that effective coherent averaging does 

not appreciably occur. In this latter case, the observed reflectivity 

is essentially an area-weighted incoherent sum of two distinct 

reflectivities, each for one of the two different SLDs. In this latter 

case, two critical Q values are observed, one corresponding to the 

material of lower SLD (Si) (below which the reflectivity is unity) and 

another determined by the SLD of the material of higher SLD (Ni). 

Between these two critical Q values the reflectivity is 50 percent, 

corresponding to the equal in-plane areas of the two materials. 

The differences between the reflectivity curves for the two cases 

shown in Fig. 2 are striking and clearly indicative of the length scale 

over which effective averaging takes place. Note that for glancing 

angles of incidence, the projected length of the transverse coherence length is greatly enhanced.

Fig. 3 summarizes the specular reflectivity results, showing reflectivities for a representative grating period in each of three classes 

– incoherent, intermediate, and coherent. In the coherent limit, the 

neutron wave packet effectively averages over a sufficient number of 

periods in the grating structure. There is only a single critical Q – that 

corresponding to a film with half the SLD of Ni on a semi-infinite Si 

substrate. In the incoherent limit, on the other hand, the neutron 

wave packet effectively sees either a Ni stripe or an intervening 

Si area – so that for a sufficient number of incident neutrons in 

a beam, two distinct critical edges are observed, as discussed 

previously. In between these two limiting cases, a more complicated 

specular reflectivity curve is observed representing a cross-over 

region where the relatively large distortions observed are also a 

manifestation of the grating structure itself, as discussed in reference 

[3]. All of the specular and non-specular measurements performed 

in this work are consistent with a value of approximately one micron 

for the effective transverse coherence of the neutron packet.

In summary, by analyzing the specular reflectivity from a set of 

well-characterized diffraction gratings of different periods, we have 

obtained a measure of the effective transverse coherence length of a 

neutron wave packet – as prepared in a typical reflectometer configured for the study of the structure of condensed matter in thin film 

form – which is of the order of one micron. The particular measure 

of transverse coherence obtained in this manner is indicative of the 

ability of the packet to effectively average over in-plane variations 

of scattering density in specular reflectivity measurements. 

References

[1] C. F. Majkrzak, C. Metting, B. M. Maranville, J. A. Dura, S. Satija, 

T. Udovic, N. F. Berk, Phys. Rev. A 89, 033851 (2014).

[2] P. A. M. Dirac, Quantum Mechanics, 4th Ed., (Oxford University 

Press, London, 1958) p. 9.

[3] N. F. Berk, Phys. Rev. A 89, 033852 (2014).

FIGURE 2: Reflectivity curves corresponding to coherent or incoherent 

averaging of two different SLDs, as described in the text. In the real space 

schematic of the grating structures, the material for the periodic rectangular 

structure is the same as the substrate and is taken to have the SLD of Si 

– the troughs in between, have the SLD of ordinary Ni. For the structure 

on the bottom (a), only a single critical Q is observed. Note that the real 

space figures are a highly schematic representation of the projection of the 

wave packet’s transverse coherence length onto the grating. In reality, the 

wavefront structure of the packet is highly distorted in the vicinity of its 

interaction with the material. Grating (b) corresponds to an incoherent sum 

of two independent areas of in-plane SLD in the film, as described in the text. 

Note the appearance of two distinct critical Q values in the reflectivity curve.

FIGURE 3: Summary of the specular reflectivity results, showing the reflectivity for a representative grating period in each of the three classes – 

incoherent, intermediate, and coherent. Error bars on the data points are 

statistical and represent one standard deviation.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 35NEUTRON PHYSICS
Improved determination of the neutron lifetime

A. T. Yue,1 M. S. Dewey,1 D. M. Gilliam,1 G. L. Greene,2,3 A. B. Laptev,4 J. S. Nico,1 W. M. Snow,5 and F. E. Wietfeldt6

T

he accurate determination of the mean lifetime of the free 

neutron addresses important problems in physics [1]. The 

neutron lifetime is used in precision tests of the weak sector 

of the Standard Model, is an important input for models of light 

element formation following the Big Bang, and is required for 

comparisons between the measured and predicted antineutrino 

flux produced by nuclear reactors [2]. High-precision measurements (1 s to 5 s total uncertainty) have been performed with two 

distinct experimental strategies, yielding the Particle Data Group 

(PDG) world average neutron lifetime of τn = (880.0 ± 0.9) s [3]. 

In the “beam” method, the absolute density of neutrons and 

the absolute decay rate are measured in a well-defined volume 

of a beam. In the “bottle” method, neutrons are confined to 

a storage vessel for varying times and the remaining neutrons 

are counted. As seen in Fig. 1, the beam and bottle measurements demonstrate reasonable internal consistency, but the 

weighted averages from the two methods differ by 2.6 σ

(∆τn ≡ τnbeam - τnbottle = (887.3 ± 2.8) s - (879.6 ± 0.8) s = (7.7 ± 2.9) s).

This discrepancy casts doubt on the accuracy of the world 

average at the level of several seconds. The discrepancy is best 

addressed by reducing the uncertainty in the comparatively lower 

precision beam experiments. To that end, we have significantly 

improved the neutron flux measurement technique used in the 

NIST beam lifetime experiment. It has been used to retroactively 

improve the determination of the neutron lifetime [4] and it 

provides a clear path to 1 s total uncertainty in a new run of the 

lifetime experiment [5].

The most precise beam neutron lifetime measurement was 

performed at the NCNR in 2000 [6, 7]. As shown in Fig. 2, the 

experiment uses an electromagnetic proton trap to determine 

the absolute rate of neutron decay in a well-defined volume 

of the beam, and a neutron monitor to measure the absolute 

density of neutrons in the trap. The neutron monitor operates 

by counting the charged particle products from the 6Li(n,t)4He 

reaction. The neutron beam passes through a thin deposit 

of 6LiF and the reaction products are counted with surface 

barrier detectors masked by precision apertures. The detection 

efficiency for the monitor is determined from the evaluated 

nuclear data file value for the 6Li(n,t)4He cross section, and from 

measurements of the areal density of the 6LiF deposit and the 

solid angle subtended by the detectors. The NIST experiment 

reported a lifetime of τn = (886.3 ± 3.4) s with the uncertainty 

dominated by the detection efficiency of the neutron monitor 

(2.7 s) [7]. Through the use of a totally absorbing neutron 

detector called the Alpha-Gamma (AG) device, we have directly 

measured the detection efficiency of the lifetime neutron 

monitor without reference to the 6Li(n,t)4He cross section 

and deposit density, circumventing the dominant sources 

of uncertainty in the prior efficiency determination.

1 National Institute of Standards and Technology, Gaithersburg, MD 20899

2 University of Tennessee, Knoxville, TN 37996

3 Oak Ridge National Laboratory, Oak Ridge, TN 37831

4 Los Alamos National Laboratory, Los Alamos, NM 87545

5 Indiana University, Bloomington, IN 47408

6 Tulane University, New Orleans, LA 70118

FIGURE 1: The neutron lifetime measurements used in the PDG 2013 world 

average. Three weighted averages (dashed lines) and their respective 1-σ

uncertainties (rectangles) are shown: beam lifetimes (red), bottle lifetimes 

(blue), all lifetimes (green).

FIGURE 2: A schematic of the NIST beam neutron lifetime experiment. 

Protons produced by neutron decay are trapped radially by a 4.6 T magnetic 

field and axially by an electrostatic potential from voltage applied to the 

electrodes. The upstream electrodes are periodically grounded to flush 

protons out to the proton detector. Simultaneously, the neutron density in 

the trap is determined with a 6Li-based neutron monitor.

36 NIST CENTER FOR NEUTRON RESEARCH NEUTRON PHYSICS
The AG device determines the flux of neutrons impinging on a 

totally-absorbing 10B-enriched boron carbide target by counting 

the 478 keV 10B(n,γ)

7Li reaction gamma rays with high-purity 

germanium (HPGe) detectors. The flux is determined from the 

measured gamma rate and the absolute detection efficiency of 

the HPGe detectors for the capture gamma. The gamma detection 

efficiency is determined in a separate calibration procedure in 

which the precisely known activity of an alpha source is successively transferred through a series of intermediate steps [8].

The AG device and beam lifetime neutron monitor were operated 

simultaneously on NG-6M, a monochromatic cold neutron beam 

(as shown in Fig. 3). The measured flux from the AG device, the 

measured rate of 6Li(n,t)4He reaction products in the neutron 

monitor, and the measured wavelength of the beam are then used 

to determine the detection efficiency of the neutron monitor for 

thermal neutrons without reference to the 6Li(n,t)4He cross section 

or the target density. As shown in Fig. 4, data taken with three 

different beam collimations show good statistical consistency 

after correction for several systematic effects that may alter the 

efficiency. Including the uncertainties from systematic effects, 

the neutron monitor efficiency has been determined to 0.06 % 

with the AG device, a five-fold improvement [9].

The measured detection efficiency is in good agreement with 

the value used in the prior work. We have verified the temporal 

stability of the neutron monitor (stability of the aperture frame 

and stability of the 6LiF deposit density) through additional 

measurements. This allows us to use the newly measured 

detection efficiency to improve the neutron flux determination 

in the lifetime experiment, yielding an improved lifetime result of 

τn = (887.7 ± 2.3) s that replaces the prior result [4]. As seen in 

Fig. 5, this results in a new world average of τn = (880.3 ± 1.1) s

and (∆τn = (888.0 ± 2.1) s - (879.6 ± 0.8) s = (8.4 ± 2.2) s), increasing

the significance of the discrepancy to 3.8 σ. It is important that 

this discrepancy be resolved through measurements at higher 

precision. The NIST experiment will continue to play an important 

role, as the improvements in neutron flux determination reported 

here allow for the possibility to achieve 1 s total uncertainty with 

the existing apparatus in a new measurement.

References

[1] D. Dubbers, M. G. Schmidt, Rev. Mod. Phys. 83, 1111 (2011).

[2] G. Mention et al., Phys. Rev. D 83, 073006 (2011).

[3] J. Beringer et al., Phys. Rev. D 86, 010001 (2012).

[4] A. T. Yue et al., Phys. Rev. Lett. 111, 222501 (2013).

[5] M. S. Dewey et al., Nucl. Instr. and Meth. A 611, 189 (2009).

[6] M. S. Dewey et al., Phys. Rev. Lett. 91, 152302 (2003).

[7] J. S. Nico et al., Phys. Rev. C 71, 055502 (2005).

[8] D. M. Gilliam, G. L. Greene, G. P. Lamaze, Nucl. Instr. and Meth. 

A 284, 220 (1989).

[9] A. T. Yue, Ph.D. thesis, University of Tennessee (2011).

FIGURE 3: Schematic of the instrument setup on NG-6M.

FIGURE 4: Normalized neutron monitor detection efficiency measurements 

with the AG device for three beam collimations. Corrections for systematic 

effects depending on beam collimation are included. The error bars are 

statistical only. The dashed black line is a weighted average of the data, 

and the grey bar represents the 1 σ uncertainty on the fit.

FIGURE 5: The neutron lifetime measurements used in the PDG 2013 world 

average after replacement of the 2005 NIST beam lifetime result with the 

2013 result.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 37NEUTRON PHYSICS
Shaken or stirred? It matters when addressing 

the dynamics and stability of macromolecular 

nanocarriers in aqueous solution

T. H. Epps, III, M. O. Sullivan, R. P. Murphy, E. G. Kelley, J. E. Seppala, T. P. Smart, and S. D. Hann

T

he solution self-assembly of macromolecular amphiphiles, 

such as block copolymers, offers an efficient strategy for 

producing well-defined nanocarriers, with applications 

ranging from drug delivery and diagnostics to nanoreactors 

and reagent recovery. Typically, the formation of nanocarrier 

architectures is dictated by processing methods that employ 

cosolvent mixtures. These fabrication strategies rely on the 

assumption that polymeric solution nanostructures are kinetically 

stable following transfer from an organic/aqueous solution 

into an aqueous medium. We recently demonstrated that 

step-changes in polymer micelle populations could occur over 

days to weeks following transfer into a highly selective solvent, 

such as water [1]. This unexpected micelle growth was critically 

dependent on the method and rate of solution agitation (Fig. 1) 

and has a major impact on the assumed stability of polymer 

assemblies for therapeutic applications.

Amphiphilic macromolecules, such as block copolymers, are 

promising for many applications as molecular design offers 

enormous chemical versatility and exquisite control over the size 

and shape of solution assemblies. Of particular interest are the 

unique material properties conferred by the macromolecular 

nature of the hydrophobic block, such as exceptionally slow 

inter-aggregate chain exchange in highly selective solvents. 

These characteristics overcome key limitations of small molecule 

aggregates by improving the retention of encapsulated cargo 

for delivery and nanoreactor applications [2].

Many common preparation methods employ cosolvent mixtures to 

enable the loading of self-assembled morphologies with various 

hydrophobic cargoes such as dyes and therapeutic agents for 

diagnostics and drug delivery applications [2]. Cosolvent methods 

are essential to solubilize both the hydrophobic cargo and amphiphilic copolymer to facilitate efficient encapsulation. As nanocarriers are routinely used in aqueous solution, these preparation 

methods also hinge on the assumption that the assemblies are 

kinetically trapped (and nanostructure is preserved) following 

transfer from an organic/aqueous solution into water. 

Although the effects of cosolvent introduction on the generation of block copolymer assemblies are well researched, the 

consequences of cosolvent removal on self-assembled structures 

typically are overlooked [1]. While some macromolecular assemblies are known to be kinetically trapped over time scales of days 

Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716

or even months, a cohesive understanding of polymeric micelle 

dynamics is still lacking [1]. In the present work, it is shown that 

significant dynamic processes occur in block copolymer micelles 

following cosolvent removal, even in highly selective solvents. 

In the absence of agitation, the micelles are stable, consistent 

with scaling theories. However, gentle agitation, which is not 

considered in many scaling theories, leads to a marked increase 

in the micelle size. The micelle sizes evolve through a bimodal 

distribution, in which well-defined step-changes in size lead to a 

monodisperse final nanostructure population with an aggregation 

number much larger than that of the starting population. 

FIGURE 1: Schematic representation of contrast conditions used to study 

chain exchange as a result of solution agitation. Micelles containing protonated PB chains in the core and either non-deuterated or deuterated PEO 

chains in the corona (lower left panel) were agitated using rapid vortex 

mixing, Couette flow, or nitrogen gas sparging. SANS was used to measure 

the scattering intensity as a function of mix time and hence to quantify the 

extent of chain exchange (lower right panels). Chain exchange between 

micelles decreases the solvent-corona contrast and the scattered intensity, 

and under certain agitation conditions, the scattered intensity gradually 

approaches that of micelles with randomly mixed hPEO/dPEO corona chains.

38 NIST CENTER FOR NEUTRON RESEARCH SOFT MATTER
The growth of poly(butadiene-b-ethylene oxide) [PB-PEO] micelles 

following solvent transfer (from tetrahydrofuran [THF]/water 

mixtures) into pure water was examined using small angle neutron 

scattering (SANS) and cryogenic transmission electron microscopy 

(cryo-TEM). Specifically, chain exchange in water was investigated 

using SANS by exploiting contrast variations and monitoring the 

temporal changes in the scattered intensity. Separate PB-PEO and 

PB-dPEO micelle solutions were prepared in an H2O/D2O mixture 

and mixed at time t = 0, giving rise to a maximum in scattered 

intensity due to contrast between the coronas and solvent. The 

lack of a temporal change in intensity in these mixed solutions 

indicated that single chain exchange was not prevalent in the 

highly amphiphilic PB-PEO systems [1].

Thus, fusion processes were examined as the other mechanism 

that could promote micelle reorganization. To visualize the micelle 

growth, cryo-TEM was employed to follow the temporal evolution 

of a micelle solution over a 21-day period following cosolvent 

removal. As one example, the data are illustrated for a solution 

that was initially in a solvent of volume fraction 43 % THF, prior 

to transfer into pure water at day 0. The core radii at day 0 

were described by a single and nearly monodisperse distribution 

centered at (5 to 6) nm. Unexpectedly, a second distinct distribution of core radii centered at (10 to 11) nm appeared after 1 day. 

This second distribution represented an approximate eight-fold 

increase in core volume or aggregation number from the initial 

distribution. The distinct bimodal distribution persisted for 

≈ 10 days, with the population weighting shifting from the smaller 

to the larger distribution over time. By day ≈ 16, the core size 

distribution exhibited a single and nearly monodisperse population 

at (10 to 11) nm. Similar behavior was noted for samples prepared 

from solutions of volume fraction 30 % THF and 50 % THF, 

suggesting that specimens prepared at high THF contents grew 

through a fusion-controlled process.

The size evolution also was examined as a function of micelle 

concentration using cryo-TEM and SANS. The cryo-TEM images 

show that on day 10/11, 2 mg mL-1 and 5 mg mL-1 solutions 

still contained an appreciable bimodal population of micelles, 

while the 10 mg mL-1 solution had transitioned to primarily 

larger micelles (Fig. 2). These micrographs suggested that the 

relative weighting of the larger population increased with micelle 

concentration and further supported that the micelles grew 

through fusion. For the SANS experiments, the micelle coronas 

were contrast-matched to the solvent (D2O) by blending PB-PEO 

and PB-dPEO polymers, thereby probing only the PB core size 

distribution. The SANS data showed a marked difference in micelle 

populations for the 2 mg mL-1 sample vs. the higher concentration 

samples (Fig. 2). However, the maxima and minima were located 

at approximately the same q-values, supporting that the larger 

micelles were the same size in all samples (Fig. 2). The bimodal 

core distribution centered at Rc ≈ 5 nm and ≈ 10 nm was in good 

agreement with the cryo-TEM results, supporting the fusion 

mechanism for micelle growth.

In summary, the distinct bimodal distribution found in the present 

work does not reflect standard predictions for micelle growth 

process [1]. Additionally, the micelle size evolution critically 

depended on solution agitation, suggesting that the growth 

may be an interfacial phenomenon. Hence, further quantitative 

studies are needed to distinguish the detailed mechanism and 

associated kinetics to fully understand the air-water interfacial 

effects on the long-term stability of macromolecular assemblies 

[3]. This relationship between processing conditions and 

subsequent dynamics has critical implications on the stability 

and overall “shelf-life” of solution nanostructures.

References

[1] E.G. Kelley, R. P. Murphy, J. E. Seppala, T. P. Smart, S. D. Hann, 

M. O. Sullivan, T. H. Epps, III, Nature Comm. DOI:10.1038/

ncomms4599 (2014).

[2] E. G. Kelley, J. N. L. Albert, M. O. Sullivan, T. H. Epps, III, 

Chemical Society Reviews 42, 7057 (2013).

[3] R. P. Murphy, E. G. Kelley, S. A. Rogers, M. O. Sullivan, T. H. 

Epps, III, (2014) submitted to ACS Macro Letters.

FIGURE 2: Cryo-TEM micrographs showing changes in micelle core radii 

between day 0 (a) and day 10 or day 11 (b) for several polymer concentrations. Scale bars are 100 nm. (c) SANS data (points) and fits (solid lines) 

for micelle solutions at different concentrations. (d) Corresponding number 

frequency distribution of core radii from fits to SANS data. Samples for the 

SANS experiments were prepared in a solvent of volume fraction 43 % THF 

and dialyzed against D2O, and SANS experiments were performed at day 11 

post dialysis to D2O. The relative percentages of the smaller (Rc < 8 nm) and 

larger (Rc ≥ 8 nm) core radii populations are shown on the frequency curves.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 39SOFT MATTER
Universal scaling of polymer diffusion 

in nanocomposites

J. Choi,1 M. J. A. Hore,2,3 J. S. Meth,4 N. Clarke,5 K. I. Winey,1 and R. J. Composto1

Nanoparticles are added to polymers to form polymer nanocomposites (PNCs), which often exhibit enhanced physical properties due to the presence of the nanoparticle component. For example, PNCs possess properties that are attractive for 

biological, energy, and sensing applications, and have received 

growing interest due to the variety of functional nanoparticles 

that are available. In addition, advances in grafting polymers 

to surfaces have lead to powerful approaches for controlling 

nanoparticle dispersion by mediating the interactions between 

the nanoparticles and the free polymer. The processing of PNCs 

into bulk materials or films depends on the mobility of polymer 

chains in the presence of the nanoparticles, which can be grafted 

with small molecules or longer polymer chains. Unfortunately, 

while polymers with and without nanoparticles exhibit similar 

dynamics, a unified picture of polymer dynamics in the presence 

of nanoparticles is not available. Previous work [1] has demonstrated that polystyrene diffusion in PNCs containing bare 

nanoparticles obeys a universal rule, and is parameterized by a 

single confinement parameter ID/2Rg, where ID is the interparticle 

distance and Rg is the radius of gyration of the diffusing polymer 

chains. The confinement parameter characterizes the effective 

size of a diffusion pathway relative to the size of the diffusing 

polymer. In this way, if ID/2Rg is small, the diffusion pathway near 

nanoparticles is small compared to the diffusing polymer, and the 

diffusing polymer is more strongly confined – leading to a slowing 

down of dynamics and a decrease in the diffusion constant. 

When bare nanoparticles are replaced with polystyrene-grafted 

nanoparticles, however, the diffusion constants do not follow this 

rule. Using a combination of self-consistent field theory (SCFT) 

and small-angle neutron scattering (SANS), we demonstrate that 

nanoparticles can appear larger or smaller to a diffusing polymer, 

depending on the molecular weight of that polymer, which 

in turn leads to an “effective” confinement parameter. When 

the polymer diffusion is instead parameterized by the effective

confinement parameter, polymer diffusion in both systems 

collapses onto a single master curve [2].

The interparticle distance, ID, is a function of the nanoparticle 

volume fraction, which in turn depends on the nanoparticle 

size. To determine the effective interparticle distance, IDeff, 

we performed SCFT calculations on a system consisting of a 

polymer-grafted nanospheres (molecular weight 87 kg/mol), 

embedded in a polymer matrix (molecular weight 160 kg/mol) that 

contains a volume fraction of 10 % of a diffusion tracer. As shown 

in Fig. 1, for a low molecular weight tracer, the volume fraction 

profile for the tracer polymer is fairly uniform as the distance to 

the nanoparticle surface decreases. In other words, the tracer 

polymer is not excluded from the grafted polymer region. On the 

other hand, for a larger tracer molecular weight (532 kg/mol, left) 

the tracer volume fraction falls off from 10 % to approximately 

5 % at a distance 2Rg from the nanoparticle surface, as indicated 

by the blue arrow. In this situation, the tracer polymer cannot 

diffuse farther into the grafted polymer layer. Therefore, the size 

of the nanoparticle appears larger to a high molecular weight 

polymer, Reff = RNP + h, where Reff is the effective nanoparticle 

radius, RNP is the physical nanoparticle radius, and h is the brush 

height that the tracer polymer cannot penetrate into. Thus, 

nanoparticles appear larger or smaller to a diffusing polymer 

depending on the molecular weight of the tracer. If the molecular 

weight of the tracer is larger than that of the grafted polymer, 

Reff > RNP; otherwise, Reff ≈ RNP. This behavior is entropic in nature, 

and due to autophobic dewetting between the two polymers. 

The effective confinement parameter IDeff is obtained from the 

effective radius.

1 University of Pennsylvania, Philadelphia, PA 19104

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

3 Case Western Reserve University, Cleveland, OH 44106

4 E.I. DuPont de Nemours and Co., Inc., Wilmington, DE 19801

5 Sheffield University, Sheffield, S10 2TN United Kingdom

FIGURE 1: Self-consistent field theory (SCFT) calculations of the density of 

the grafted polymer (black), matrix polymer (red), and tracer polymer (blue) 

as a function of distance from the nanoparticle surface for two different 

tracer molecular weights. The arrow denotes the brush thickness h that 

the tracer polymer cannot penetrate. For example, h = 0 implies that the 

tracer polymer penetrates through the entire brush.

40 NIST CENTER FOR NEUTRON RESEARCH SOFT MATTER
The SCFT results were validated by small-angle neutron scattering 

(SANS) measurements. PNCs were synthesized that matched the 

parameters of the SCFT calculations. Polystyrene (PS) grafted SiO2

nanospheres (RNP = 25 nm, PS molecular weight 87 kg/mol) were 

added to a hydrogenated polystyrene matrix (molecular weight 

160 kg/mol) that contained a volume fraction of 10 % deuterated 

polystyrene (dPS, 23 kg/mol or 532 kg/mol). The dPS provided 

contrast in the system by changing the scattering length density 

of the polymer “shell” surrounding the nanoparticles. Shown 

on the left in Fig. 2 are the scattering length densities (SLDs) of 

the polymer shell around the nanoparticle, obtained from the 

tracer polymer volume fractions in Fig. 1. For the 23 kg/mol 

tracer, the ratio of deuterated polymer to hydrogenated polymer 

is very close to that in the bulk of the sample (i.e., away from 

the nanoparticles). Thus, there is little contrast between the two 

components and only the bare nanoparticles can be observed in 

SANS (i.e., the nanoparticles are “hard” nanoparticles). On the 

other hand, for larger tracer molecular weights, the deuterated 

tracer is excluded from a region of size h near the nanoparticle, 

which leads to a large contrast between these two regions. In 

this case, SANS sees the bare nanoparticles with a surrounding 

shell of hydrogenated polymer (i.e., the nanoparticles are “soft” 

nanoparticles). When these values are used to fit the SANS 

intensities with a modified core/multi-shell model (Fig. 2, right), 

the fits reproduce the scattering data quite well, indicating the 

validity of the SCFT description of the system.

By using this ability to transform nanoparticles from hard to soft 

by varying the molecular weight of the diffusing polymer, we 

have uncovered a universal scaling rule for polymer diffusing in 

nanocomposites. Diffusion constants of deuterated polymers with 

varying molecular weights diffusing into PNCs containing a volume 

fraction of 5 % SiO2 nanoparticles were measured using elastic 

recoil detection (ERD). The diffusion constants, D, were normalized 

by D0, the diffusion constant measured in the absence of nanoparticles. Fig. 3 shows the scaled diffusion constant as a function of 

the effective confinement parameter IDeff/2Rg. As the confinement 

parameter decreases, the diffusion constant decreases substantially compared to D0 due to the presence of entropic bottlenecks 

that hinder diffusion into the PNC. Remarkably, the scaled diffusion constants for both the hard and soft nanoparticle systems 

fall onto a single master curve, indicating a universal diffusion 

behavior in both classes of systems.

By combining self-consistent field theory and small-angle neutron 

scattering measurements, we have demonstrated that the effective size of a polymer-grafted nanoparticle can be larger than the 

physical size of the nanoparticle core, depending on the molecular 

weight of the diffusing polymer. For diffusing polymers with large 

molecular weights, relative to the brush, the grafted polymer 

exclude the diffusing polymers from the grafted layer, leading to a 

larger effective size, and a larger degree of confinement. Plotting 

the scaled diffusion constant D/D0 as a function of IDeff/2Rg

yields a single master curve that describes polymer diffusion 

into polymer nanocomposite systems [2].

References

[1] S. Gam, J. S. Meth, S. G. Zane, C. Chi, B. A. Wood, M. Seitz, K. I. 

Winey, R. J. Composto, Macromolecules 44, 3494 (2011).

[2] J. Choi, M. J. A. Hore, J. S. Meth, N. Clarke, K. I. Winey, R. J. 

Composto, ACS Macro Letters 2, 483 (2013).

FIGURE 2: (Left) Calculated scattering length density (SLD) from SCFT in 

the grafted polymer layer as a function of distance from the nanoparticle 

surface. The red curve corresponds to a 23 kg/mol tracer polymer, and blue 

to a 532 kg/mol tracer polymer. The scattering length density is higher for 

the lower molecular weight tracer because more deuterated polymer is 

present within the brush. (Right) Small-angle neutron scattering (SANS) 

measurements and fits, according to a modified spherical core-shell model 

using the calculated SLDs.

FIGURE 3: A plot of the scaled diffusion constant versus the confinement 

parameter yields a master curve. Closed and open symbols represent 

polystyrene diffusion in nanocomposites with soft and hard nanoparticles, 

respectively. The effective confinement parameter was determined using 

SCFT calculations, such as those shown in Fig. 1.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 41SOFT MATTER
Probing the relationship between water content 

and chain dynamics in fuel cell membranes 

K. A. Page,1 B. W. Rowe,1 K. Masser,1 and A. Faraone2,3

F

uel cells based on polymer electrolyte membranes (PEM) 

show promise as a means of energy conversion for a wide 

range of applications both in the transportation sector 

and for stationary power production due to their high charge 

density and low operating temperatures. Perfluorosulfonate 

ionomers (PFSI’s), particularly Nafion, are one of the most 

widely studied classes of materials for use as PEMs in fuel cell 

applications. In order to understand the performance of these 

membranes, it is necessary to understand the structure, water 

dynamics, and proton conductivity in these materials over a 

large range of relative humidity, temperatures, and processing 

conditions. Water and polymer dynamics play a critical role in 

the performance (i.e., proton conductivity) and durability of 

membrane materials in operating hydrogen fuel cells. Ultimately, 

researchers would like to find ways to reduce the amount of 

water necessary for high proton conductivity because the fuel cell 

could then be operated at higher temperatures, which improves 

the efficiency of the cell. Therefore, many studies have focused 

on understanding the bulk water transport with considerable 

effort to learn how this transport is related to the nanostructure 

of the membrane. Researchers have used neutron techniques 

to investigate the local water dynamics within the nanoscale 

structures present in the material and to correlate the motions of 

water at the nanoscale to the bulk transport of water, which is 

critical to the performance of these materials in electrochemical 

devices. While the focus has mainly been on water, the complex 

structural features of these materials as well as the relationship 

between the water (both local and macroscopic) and the polymer 

chain dynamics have received less attention. However, if any 

advances are to be made in the elucidation of the fundamental 

properties of water transport, one must develop a working 

knowledge of the interplay between water dynamics/transport 

and chain motions. One way to approach this problem is to 

measure the collective structural dynamics in hydrated PFSI 

materials at elevated temperatures and to relate those dynamics 

to the content and behavior of water. In this work, we have used 

neutron spin echo (NSE) spectroscopy and dielectric relaxation 

spectroscopy (DRS) to investigate the relationship between 

water content and chain dynamics in Nafion membranes [1, 2].

Figure 1 demonstrates typical results from the NSE measurement which is the normalized intermediate scattering function, 

S(Q,t)/S(Q,0), as measured for dry (λ ≈ 0) and hydrated (λ ≈ 16) 

Nafion membranes at 335 K (where λ is the moles of water per 

mole of sulfonic acid groups in the polymer). The measured 

S(Q,t)/S(Q,0) is associated with motions occurring on the length 

scale of the inter-chain distances (ca. 5 Å) of the polymer 

backbone as determined from the coherent structure-factor 

(inset, Fig. 1). The data was fit with a Kohlrausch-Williams-Watts 

(KWW) equation (inset, Fig. 1) to determine the time scale 

associated with the polymer chain motions both as a function of 

water content and temperature. Clearly, S(Q,t)/S(Q,0) decays at 

a faster rate with the addition of water which indicates that the 

motions occurring on the length scale of the inter-chain distance 

are occurring at shorter time scales. Moreover, at a given water 

content a similar behavior is exhibited with increasing temperature. A summary of the quantitative analysis of the relaxation 

1 National Institute of Standards and Technology, Gaithersburg, MD 20899

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

3 University of Maryland, College Park, MD 20742

FIGURE 1: The normalized intermediate scattering function, S(Q,t)/S(Q,0), 

for a nominally dry and hydrated (λ = 16) Nafion membrane at Q = 1.2 Å-1. 

The Q value was chosen to coincide with the peak in the coherent structure 

factor associated with inter-chain scattering of the Nafion polymer backbone (inset). The S(Q,t)/S(Q,0) was fit with the KWW equation as shown in 

the graph, where τKWW is the relation time of the polymer chains and β is 

related to the distribution of relaxation times observed. Notice the remarkable 

increase of the polymer chains’ mobility as the water content increases. Error 

bars represent one standard deviation in the measured scattering intensity.

42 NIST CENTER FOR NEUTRON RESEARCH SOFT MATTER
process(es) can be found in Fig. 2. The time scale of the backbone 

dynamics, τKWW, undoubtedly has a strong dependence on both 

λ and temperature. Essentially, as the temperature and the water 

content, λ, increase; τKWW decreases accordingly, indicating that 

the chain motions are becoming faster, which is to be expected. 

With increasing levels of water, the electrostatic interactions 

are weakened and the polymer is effectively plasticized by the 

water molecules. Additionally, τKWW begins to decrease less 

significantly with λ for values greater than approximately 6. 

Interestingly, researchers have shown that the effective diffusivity 

of water through the membrane and the local water dynamics 

both seem to plateau at approximately the same water content 

(λ ≈ 6). This is evidence that there is a strong inter-dependence 

of the dynamics of water and the polymer chains. As with the 

local water dynamics, at water contents greater than λ ≈ 6, 

the chain dynamics seem to be approaching a plateau and the 

relaxation times of the chains are no longer, to a large degree, 

being plasticized by the presence of additional water molecules. The increased mobility in molecular relaxations induced 

by the presence of water points to the molecular origins of the 

temperature- and humidity-dependent softening mechanisms in 

Nafion and other perfluorinated sulfonic acid (PFSA) membrane 

materials. Moreover, we have determined the activation energy, 

Ea, for the segmental dynamics through an analysis of the 

temperature dependence of relaxation times measured and 

found a decrease in the activation energy for this process with 

increasing water content. This is a similar behavior that has been 

observed by Lingwood and coworkers [3] for the energetics of 

water transport in Nafion. Taking both studies into consideration, 

it is important to note that the activation energy for water transport at low water contents is comparable to that measured for 

the polymer chain motions as measured by both NSE and DRS [4]. 

This is strong evidence that the water/proton transport in these 

materials is strongly coupled to the polymer chain dynamics.

We have successfully measured the chain dynamics as a function 

of water content and temperature using NSE spectroscopy and 

have demonstrated that the chain dynamics become faster with 

increasing temperature and water content. And, more importantly, that the energetics of water transport and chain dynamics 

are quite comparable at relatively low water contents. These 

results provide evidence that there is a strong coupling between 

the water transport and the polymer segmental dynamics at low 

water contents in perfluorinated sulfonic acid (PFSA) membrane 

materials. These results have strong implications if materials 

capable of achieving high performance at low water content are 

to be engineered. Going forward, this information aids chemists in 

the design of polyelectrolyte membrane materials that have higher 

proton conductivity at low water contents by finding ways to 

incorporate acid groups with fast dynamics at low water contents 

or decoupling the water and polymer dynamics altogether.

References

[1] Y. Wang, K. S. Chen, J. Mishler, S. C. Cho, X. C. Adroher, Appl. 

Energ. 88 (4), 981 (2011).

[2] K. Mauritz, R. Moore, Chem. Rev. 104, 4535 (2004).

[3] M. D. Lingwood, Z. Y. Zhang, B. E. Kidd, K. B. McCreary, 

J. B. Hou, L. A. Madsen, Chem. Comm. 49, 4283 (2013).

[4] K. A. Page, B. R. Rowe, K. A. Masser, A. Faraone, J. Polym. Sci. 

Part B Polym. Phys. 52 (9), 624 (2014). 

FIGURE 2: Time scale of backbone dynamics, τKWW, at various water contents 

(dry, λ = 6, and λ = 16) at ( ) 335 K, ( ) 350 K, ( ) 365 K, ( ) 380 K, and 

( ) 395K. Error bars represent one standard deviation in the determination 

of τKWW from fitting of the KWW equation to the intermediate scattering 

S(Q,t)/S(Q,0). Dashed lines are guides for the eye.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 43SOFT MATTER
Observation of spatially dependent 

heterogeneity of constrained local motions 

of rubber in carbon black nanocomposites 

J. H. Roh,1 M. Tyagi,2,3 and C. M. Roland4

Understanding the molecular dynamics and vitrification 

transition of polymers at the interface with fillers remains a 

challenge for material scientists. The physical and chemical 

properties of polymers in proximity to substrates are directly 

coupled to the local dynamics at the interface. The binding 

affinity can give rise to dynamic heterogeneity of the motions, 

as reflected in spatial and temporal correlations, as well as a 

distribution of relaxation times [1].

However, the physical interactions between polymers and 

interfaces and their effect on dynamical properties remain 

poorly understood, with discordant conclusions from various 

experimental studies. It is more intuitive that binding of polymer 

segments to hard particles suppresses local motions, to increase 

both the relaxation time [2] and the length scale of the cooperativity [3]. Interestingly, a few quasielastic neutron scattering 

(QENS) studies showed increased librational mobility of the 

polymer chains in the glassy state due to the presence of carbon 

black (CB) nanoparticles. Accordingly, there is no clear distinction 

between backbone units adsorbed at the surface of a substrate 

and local segments immobilized by their spatial proximity to 

the interface.

Our quasielastic scattering studies aimed to investigate how 

dynamic heterogeneity and flexibility of 1,4-polybutadiene (PBD) 

is influenced by its physical interactions with CB particles. The 

initial composition of carbon (volume fraction) of 20.5 % in the 

composite increased to 60 % after extracting PBD chains that 

did not bond to CB particles. Quasielastic neutron scattering 

experiments were conducted using the High Flux Back-Scattering 

(HFBS, NG2) and Disk Chopper (DCS, NG4) spectrometers. The 

dynamic scattering function, S(Q,E), was measured at HFBS 

with an energy resolution of 0.8 μeV up to 17 μeV; the Q range 

was 0.31 Å-1 to 1.71 Å-1. The boson peak of neat PBD and the 

nanocomposite was measured at DCS with energy resolution 

of about 25 μeV. The fraction of incoherent scattering cross 

section of H-atoms in the polymers was estimated to be 94 % 

of the total scattering for neat PBD and 82 % for the extracted 

nanocomposite, ensuring that the measured data represent 

dynamic scattering functions of PBD chains only. The wavevector 

(Q) dependent Kohlrausch-Williams-Watts (KWW) equation was 

used to obtain the spatial dependence of the local segmental 

relaxation times (τα).

 ΦKWW(Q,t) ∝ exp(-[t/τα(Q)]β(Q) )

Since the accessed dynamic range of neutron scattering is too 

narrow to determine the values of both the stretch exponent β

and the relaxation time, the former was obtained from dielectric 

measurements on the same material.

The spatially dependent relaxation times from the quasielastic 

neutron scattering measurements show a transition from 

Gaussian to non-Gaussian behaviors. At small Q (below ≈ 1 Å-1) 

where the first maximum of the static structure factor emerges, 

the microscopic motions exhibit simple Gaussian diffusion, with 

τβ

α ~ Q-2. At larger Q, the spatial dependence is much weaker, 

and is referred to as sub-linear diffusion. Such behavior is 

predicted by various theoretical models, including mode-coupling 

theory (MCT), jump diffusion models, and caging-decaging 

fractals [4, 5].

1 Center for Self-assembly and Complexity, Institute for Basic Science, Pohang, Republic of Korea, 790-784

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

3 University of Maryland, College Park, MD 20742

4 Chemistry Division, Code 6120, Naval Research Laboratory, Washington DC 20375

FIGURE 1: Incoherent dynamic structure factors at 300K at the indicated 

wavevectors for neat PBD (circles) and the nanocomposite (triangles). Dashed 

line is the resolution function measured at 4 K.

44 NIST CENTER FOR NEUTRON RESEARCH SOFT MATTER
than that for the neat PBD at higher temperatures (> 240 K). 

The difference is proportional to the amount of hydrogen atoms 

immobilized in the nanocomposite. Analysis of boson peaks at 

60 K revealed that the number of mobile sites involving only the 

fast process and collective vibrations is essentially the same for 

the neat polymer and the nanocomposites. This shows clearly 

that only the segmental motions of polymers are affected by 

the binding affinity of the nanoparticle.

Our main result is that binding of PBD chains to the carbon 

particle surface slows the segmental motions and increases 

the heterogeneity of the dynamics. We also found that the 

spectral stretching and change in τα are spatially dependent. 

Both the breadth of the relaxation peak and the relaxation time 

are larger in the CB nanocomposite. The fact that this slowing 

down is observed primarily at shorter length scales implies that 

the constraints on the chains from the particles depend on the 

proximity of a segment to the particle surface.

References

[1] M. D. Ediger, Ann. Rev. Phys. Chem. 51, 99 (2000).

[2] C. G. Robertson, C. M. Roland, Rubber Chem. Technol. 81, 

506 (2008).

[3] F. W. Starr, J. F. Douglas, Phys. Rev. Lett. 106, 115702 (2011).

[4] R. Zorn, Phys. Rev. B 55, 6249 (1997).

[5] B. Vorselaars, A. V. Lyulin, K. Karatasos, M. A. J. Michels, 

Phys. Rev. E 75, 011504 (2007).

[6] J. H. Roh, M. Tyagi, T. E. Hogan, C. M. Roland, Macromolecules 

46, 6667 (2013).

[7] J. H. Roh, M. Tyagi, T. E. Hogan, C. M. Roland, J. Chem. 

Phys. 139, 134905 (2013).

FIGURE 2: Local segmental relaxation times from QENS for (a) unfilled 

PBD with the value of the stretch exponent obtained from dielectric and 

mechanical spectroscopy. (b) extracted nanocomposite with the β(Q) (plotted 

in the inset) taken to be the values giving conformance to the Gaussian 

approximation for < 0.8 Å-1, and fixed at 0.41 for higher Q. Lines are least 

squares fits having a slope equal to −2 at small Q.

FIGURE 3: Quasielastic incoherent structure factor (QISF) for the nanocomposite and the neat PBD. These QISF values were averaged for Q ≥ 1.16 Å-1.

The stretch exponent for neat PDB was determined from its 

dielectric spectrum, yielding β = 0.41. For the filled polymer, 

β = 0.38 was found from the mechanical shear loss modulus (G′′) 

peak, although there is some deviation at lower frequencies [6]. 

Fig. 1 clearly shows that the dynamic structure function, S(E) for 

the nanocomposite is narrower than that for neat PBD, which is 

a consequence of greater constraints on the segmental motions 

[6]. For the neat PBD, the Q-dependence of the relaxation times 

is shown in Fig. 2a. For Q < 1 Å-1 the Gaussian approximation 

holds, τα

0.41 ~ Q-2. At larger Q ranges, the behavior changes, with 

the Q-dependence becoming weaker, τα

0.41 ~ Q-0.9. This non-Fickian 

diffusion implies more local and/or isolated motions. 

We calculated the β value using the expected τα

0.41 ~ Q-2/β behavior 

for small Q’s (Fig. 2b). Similar to the Q-dependence of relaxation 

times for neat PBD, a transition to a weaker Q-dependence is 

observed for the nanocomposite at larger Q. The β(Q) values for 

the nanocomposite are plotted against Q in the inset to Fig. 2b [6]. 

Fig. 3 shows the quasielastic incoherent structure factor (QISF), 

reflecting the more mobile fraction of the local motions at the 

accessed timescales [7]. QISF for the nanocomposites is less 

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 45SOFT MATTER
Development of a neutron microscope

D. S. Hussey,1 D.L. Jacobson,1 D. Liu,2 B. Khaykovich,2 M.V. Gubarev,3 and M. Arif1

An effective neutron lens is hard to find. To be a good lens 

for light, neutrons, X-rays, etc., a material must substantially 

change the path of the incoming wave. The refractive index 

of the material characterizes this change and the refractive index of 

vacuum is 1 (air is also close to vacuum). Many materials strongly bend 

visible light, for instance the refractive index of polycarbonate (used 

in reading glasses) is about 1.6, a 60 % relative change. The situation 

is completely different for neutrons, for which the refractive index 

for polycarbonate differs from air by only 0.001 %, and the focal 

length of such a lens is hundreds of meters. However, neutrons can 

be focused in a few meters by reflection from curved surfaces and 

recent efforts at NASA will enable the development of a truly effective 

neutron lens and lead to the world’s first neutron microscope.

Lens materials for soft X-rays and cold neutrons have similar, small 

refractive indices. Astronomers have developed reflective optics 

in order to image faint X-ray sources with telescopes such as the 

CHANDRA X-ray observatory. This optics was first proposed by 

Hans Wolter and is based on reflection from two confocal conic 

sections [1]. The two reflections cancel coma, meaning that this 

optics possess good off-axis imaging properties. The advance in this 

technology that NASA has made is to create high resolution mirrors 

from thin nickel foils [2] rather than CHANDRA’s mirrors which are 

thick, highly polished glass substrates coated with iridium. Nickel 

is an excellent neutron mirror and thin foils allow nesting several 

such mirrors in order to increase the solid angle of the optics. NASA 

continues to improve the resolution of these mirrors and believes 

that an angular resolution of 1 arcsec will be obtained in the very 

near future. With a focal length of 4 m, the spatial resolution of 

such a lens is about 15 μm; further improvements in mirror quality 

will enable spatial resolution of about 1 μm [3].

Without a lens, neutron imaging uses pinhole optics geometry, where 

the pinhole diameter is on the order of a centimeter. With such a 

large aperture, the object must be placed as close to the detector as 

possible to obtain the best spatial resolution. This means that one 

cannot magnify the image and to improve the achievable spatial resolution one can only improve the detector; currently the best neutron 

imaging detector has a resolution of about 15 μm. To image a thick 

object at high spatial resolution requires the use of small apertures 

which in turn strongly reduces the neutron intensity and results in 

long exposure times – typical exposure times for a 15 μm image 

are about 20 minutes. On the other hand, a lens determines the 

image spatial resolution and does not require one to use such strong 

collimation – for an image with 15 μm spatial resolution, the exposure 

time could be reduced by a factor of 100. As well, a lens can magnify 

the image which improves the resolution of the detector – a magnification of 10 will improve the resolution of the best detectors to about 

1 μm. These dramatic improvements will enable neutron imaging to 

contribute to many new areas of materials science. 

A prototype neutron microscope was built on the NG-1 beam line to 

demonstrate the concept [4]. The lens was designed for magnification 

of 4 with an overall focal length of 3.2 m. The measured spatial resolution of the images was about 75 μm which was in agreement with the 

angular resolution of about 110 μrad measured by X-rays. The effect 

of image magnification and increased intensity are shown in Figure 1 

where images of a pinhole array with 100 μm wide holes on 200 μm 

spacing using conventional neutron imaging and microscope neutron 

imaging are compared. The intensity in the microscope is increased 

by 5 and the holes in the center of the array are clearly distinguished 

in the neutron microscope image whereas they are blurred in the 

conventional image. This proof of concept measurement has spurred 

the development of an optimized neutron microscope at the NCNR, 

and it is anticipated that user operation will begin by 2017.

References

[1] H. Wolter, Ann. Der Physik 10, 52 (1952).

[2] M.V. Gubarev et al., NASA, assignee. Patent 8,575,577 (2013).

[3] K. Kilaru, B. D. Ramsey, M. V. Gubarev, D. A. Gregory, Opt. 

Eng. 50, 106501 (2011).

[4] D. Liu et al., Appl. Phys. Lett. 102, 183508 (2013).

1 Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899

2 Massachusetts Institute of Technology, Cambridge, MA 02139

3 NASA Marshall Space Flight Center, Huntsville, AL 35812

FIGURE 1: Images of a pinhole mask with conventional neutron imaging 

(left) and the prototype neutron microscope (right). The individual pinholes 

are clearly visible only with the neutron microscope.

46 NIST CENTER FOR NEUTRON RESEARCH ADVANCES IN MEASUREMENT
NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899

A scaling law to describe the average 

local structure of biomolecules

M. C. Watson and J. E. Curtis

S

mall-angle neutron and X-ray scattering have become 

invaluable tools for probing the nanostructure of molecules 

in solution. It was recently shown that the definite integral 

of the scattering profile exhibits a scaling (power-law) behavior 

with respect to molecular mass [1]. We have derived the origin of 

this relationship, and shown that the integrated scattering profile 

can be used to identify differing levels of disorder over local 

(3 nm) length scales [2].

Proteins and polymers in solution have many common features. 

Like a polymer chain, proteins are composed of a long chain of 

monomer units. The degree of folding for both polymers and 

proteins is strongly influenced by their interactions with the solvent. 

The global structure of many proteins is consistent with Flory’s 

scaling law for polymers, Rg = R0Nν where Rg is the radius of 

gyration, N is the number of chain segments, and R0 is the length 

of each segment. The value of ν lies in the range 1/3 < ν < 3/5, 

and depends on the nature of the polymer chain. Experimental 

measurements have found that unfolded proteins exhibit the 

behavior of a self-avoiding random walk (ν = 0.588). When interactions between the solvent and chain are sufficiently unfavorable, 

polymers collapse into a compact shape (ν = 1/3). This prediction 

is in good agreement with measurements of globular proteins.

Unlike polymers, however, globular proteins adopt conformations specific to their amino-acid sequence and physiological role. 

Despite the overall scaling trend described by Flory, the spread in 

the experimental data is large. Two proteins with the same number 

of residues can have radii of gyration that differ by an order of 

magnitude. Although Flory’s scaling law offers a qualitative model 

of protein size, it does not provide a structural description that is 

closely obeyed by all proteins. Calculating the definite integral of 

the small-angle scattering profile, Vc(qm), provides a quantity that 

shows clear differences depending on the degree of disorder of a 

protein. For a given qm, Vc(qm) is larger as the protein becomes more 

disordered. This is shown clearly in Fig. 1 for three different protein 

structures. Then, constructing a scaling similar to Flory: Vc(qm) = aNμ

and analyzing more than 9000 proteins provides a master scaling 

showing clear trends based on the amount of disorder in the 

protein [2].

Our analysis was applied to both globular and intrinsically disordered proteins. For nearly all cases, the integrated scattering profile 

scales with the number of chain segments, but exhibits much less 

dispersion, reflecting similarities in density on length scales below 

3 nm. Integrating to a finite qm corresponds to scanning the entire 

particle with a probe of radius 2π/qm, providing structural information that cannot be directly obtained from the scattering profile 

itself. In addition, we have shown how an individual molecule’s 

deviation from this scaling trend can be used to quantify its degree 

of disorder. For a given number of residues, the disorder and 

shape of any two molecules can be compared by measuring their 

respective Vc(qm). The integrated profile of a new molecule can 

therefore be compared with previous measurements to infer its 

degree of disorder and/or asphericity. This general framework for 

interpreting the integrated profile is not restricted to proteins, and 

may be applied to other macromolecules. The integrated profile can 

also be used in concert with other measurements to gain a deeper 

understanding of molecular form and function.

References

[1] R. P. Rambo, J. A. Tanier, Nature 496, 477 (2013).

[2] M. C. Watson, J. E. Curtis, Biophys. J. 106 (11), 2474 (2014). 

FIGURE 1: Degree of disorder as revealed by Vc(qm) and the unitless Kratky 

Plot for a compact quasi-spherical globular protein, a partially folded protein, 

and and intrinscially disordered protein IDP.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 47ADVANCES IN MEASUREMENT
Comparison of INAA and LC-ICP-MS for the 

determination of As species in marine tissues

R. Zeisler,1 L. L. Yu,1 R. Oflaz,1 V. M. O. Carioni,2 and C. S. Nomura3

Arsenic (As), a well-known toxic element and proven human 

carcinogen, remains a major human health concern. It can 

occur in high concentrations in products used for human 

consumption, for example as arsenate of geological origin in some 

drinking waters and organic arsenicals in marine organisms. With 

the introduction of regulations for As species in foodstuffs and for 

environmental control, it has become more important to quantify 

the amount of arsenic species present. To address this concern, new 

reference materials (RMs) for validation and quality assurance of As 

speciation measurements are being developed. Initial studies involve a 

tuna tissue RM developed in Brazil (CRM 1101 Tecido de Atum) [1, 2], 

a candidate seaweed Standard Reference Material (SRM 3232 Kelp), 

and several marine certified RMs as controls. The aim of this work is 

to acquire traceable quantitative results for total As in whole samples 

and in extracts containing As species. Instrumental neutron activation 

analysis (INAA) is well suited for such measurements to validate the 

As mass fraction determined by liquid chromatography combined 

with inductively coupled plasma mass spectrometry (LC-ICP-MS).

For tuna tissue, INAA was used to determine total As and trace 

elements in original solids, extracted solids, and in extracts as well 

as LC fractions; LC-ICP-MS was limited to the determination of As 

species in extracts. Extracts were used for quantitative As species 

evaluation with LC-ICP-MS incorporating internal standards and single 

point standard addition, while the sum of all As fractions was monitored by INAA. Typical results are shown in Table 1 for three certified 

RMs where excellent agreement with certified values is achieved. 

Differences between the techniques may be explained by the substantial dilution required by LC-ICP-MS resulting in very low mass fractions 

of other species in the extracts not being detected, and/or inadvertent 

blank contributions in INAA.

TABLE 1: Results for certified RMs after ultrasonic bath extraction using acetone/

methanol/H2O (1:1:1). Mass fractions values are for As (not the compound); 

uncertainties are one standard deviation for DORM-3, DOLT-3 and BCR 627 

(n = 3), and expanded uncertainties for certified values.

CRM

Extracted 

As 

(LC-ICP-MS) 

(mg/kg)

Extracted 

As 

(INAA) (mg/

kg)

Remaining 

As (INAA) 

(mg/kg)

Total As 

Calculated 

(mg/kg)

Certified 

value for 

total As 

(mg/kg)

DORM-3 5.71 ± 1.01 5.58 ± 0.51 1.44 ± 0.01 7.02 ± 0.51 6.88 ± 0.30

DOLT-3 8.10 ± 0.36 8.93 ± 0.22 1.21 ± 0.18 10.13 ± 0.20 10.2 ± 0.5

BCR 627 4.15 ± 0.10* 4.28 ± 0.18 0.47 ± 0.11 4.75 ± 0.17

4.81 ± 0.11**

4.8 ± 0.3

*sum of AB + DMA, measured AB = 3.99 ± 0.08; DMA = 0.148 ± 0.010; certified 

values: AB = 3.91 ± 0.23; DMA = 0.15 ± 0.02.

**original solid measured by INAA.

The measurement of the aforementioned species, mainly the arsenobetaine (AB), plus the dimethyl arsinic acid (DMA) using LC-ICP-MS 

is widely used and can be considered reliable. Complementing these 

measurements with INAA for value assignment in an RM delivers 

validated results. Expanding these measurements to nutritional 

supplements like seaweed presents a challenge, in part identifying a 

traceable As species. We selected two widely consumed species of 

seaweed, laver and kelp, as candidates for the developmental work.

The As species in the seaweeds are assessed with anion exchange 

LC-ICP-MS. Three major un-identified arsenic species are found in 

kelp (Fig. 1) and subsequently identified by electrospray ionization 

ion trap time-of-flight mass spectrometry (ESI-IT-TOF) as As-sugars. 

The individual fractions shown in the chromatogram are collected, 

concentrated, and determined by INAA. These INAA results are 

then used to calibrate the peaks in the LC-ICP-MS chromatogram.

The investigations have laid out a roadmap towards the value assignment and certification of As species in marine tissue and related RMs. 

Species, including those not available as standards, e.g., the arsenosugars found in kelp, can be accurately determined by INAA and used 

as calibrants. INAA and LC-ICP-MS thus were successfully used as 

comparable and complementary techniques for characterization and 

traceability studies related to the development of RMs for As species.

References

[1] V. M. O. Carioni, R. Chelegao, J. Naozuka, C.S. Nomura, Accred. 

Qual. Assur. 16, 453 (2011).

[2] V. M. O. Carioni, C. S. Nomura, L, L. Yu, R. Zeisler, J. Radioanal. 

Nucl. Chem. 299, 241 (2014).

1 Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899

2 Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre-SP, Brazil

3 Universidade de Sao Paulo, Instituto de Quimica, Sao Paulo-SP, Brazil

FIGURE 1: LC-ICP-MS chromatogram of kelp extract overlaid with 

columns indicating the amount of As determined by INAA. The column 

width represents the collection time from the chromatography column; 

the height is the mass of As (ng) including blank. Monomethylarsonic acid 

(MMA) was added as an internal standard.

48 NIST CENTER FOR NEUTRON RESEARCH ADVANCES IN MEASUREMENT
Wide-angle polarization analysis 

with neutron spin filters

T. R. Gentile,1 Q. Ye,1,2 W. C. Chen,1,2 S. Watson,1 J. Anderson,1 J. Fuller,1 A. Kirchhoff,1 R. W. Erwin,1

Y. Qiu,1,2 J. A. Rodriguez-Rivera,1,2 C. Broholm,1,3 and Y. Nambu4

Many neutron experiments would benefit from the capability 

to perform polarization analysis over a wide range of angles. 

However, polarization analysis generally yields an order of 

magnitude or more decrease in data collection rates, making such 

experiments highly demanding. The Multi-Axis Crystal Spectrometer 

(MACS) [1], was specifically designed for high neutron flux, but 

polarization analysis was not part of its original design scope. While 

neutron spin filters (NSFs) based on nuclear spin-polarized 3He gas 

have been routinely applied at the NCNR [2] to small-angle neutron 

scattering (SANS) and thermal neutron triple-axis spectrometry (TAS) 

instruments, various technical developments were required to apply 

NSFs to MACS. Recently all the elements have come together, in 

particular the unique polarized 3He cells needed for the 220-degree 

range of scattering angles on MACS. In April 2014 the first polarized 

neutron scattering experiment utilizing these wide-angle cells was 

performed, with the goal of establishing the direction of magnetism 

in the triangular lattice antiferromagnet NiGa2S4. Here we describe 

the apparatus for wide-angle polarization analysis [3] and the 

performance in this first experiment. 

Neutron spin filters are based on the spin dependence of the neutron 

absorption cross section of 3He gas. An ideal NSF is a volume of 3He 

gas in which all the nuclear spins are aligned. Neutrons with spin 

antiparallel to the 3He nuclear spin are absorbed by the gas, and for 

a sufficient thickness of 3He the transmitted neutron beam is highly 

polarized. Spin-polarized 3He gas is produced by optical pumping, 

which effectively transfers angular momentum from circularly 

polarized laser light to the 3He nuclei. An intermediary that absorbs 

the laser light is required for this transfer, which for our method of 

spin-exchange optical pumping is provided by an alkali-metal vapor 

contained within the glass 3He cell heated to ≈ 490 K. Due to space 

constraints, the optical pumping is typically done off the beam line, 

hence the polarization storage time (“relaxation time”) is a key parameter. The relaxation time is maximized by using carefully prepared 

blown glass cells in which depolarization of 3He on the cell walls is 

minimized. In addition, a magnetic field with homogeneity of a few 

parts in 104 per cm or better is required to reduce relaxation due to 

spin flips from transit of 3He atoms through magnetic field gradients.

Figure 1 shows the polarization analysis apparatus for MACS, with 

the sample cryostat removed. The neutron beam passes through an 

end-compensated aluminum-wire solenoid that contains the 3He 

cells and the sample and provides a 3 mT uniform magnetic field. 

The beam passes through a cylindrical polarizer cell and is incident 

on a sample (not shown) at the center of the solenoid. The polarization of scattered neutrons is analyzed by two cells on either side of 

the incident beam, each of which covers an angular range of up to 

110 degrees. To control the direction of the incident beam polarization via nuclear magnetic resonance without affecting the analyzer 

cells, the polarizer cell is contained within a radio-frequency (RF) 

solenoid surrounded by an RF shielding box. After the polarized cells 

are installed, the “thimble” shown in the right photo is mounted to 

the MACS sample stage to receive the sample cryostat.

During the experiment, the typical initial 3He polarization in both the 

polarizer and analyzer cells was between 70 % and 80 %. For the 

3.7 meV energy of this elastic experiment the typical initial flipping 

ratio was nearly 30 with roughly an order of magnitude decrease 

in neutron flux for the desired spin state. Given the intense incident 

beam on MACS and high 3He polarization the initial polarized beam 

flux on the sample was approximately 3 x 107 cm-2 s-1. The relaxation 

times of the cells on MACS were between 90 h and 260 h. The polarization in the polarizer cell was routinely flipped with only 0.1 % loss 

per flip and essentially no effect on the analyzer cells. Measurements 

of non spin-flip scattering and spin-flip scattering were performed 

at various temperatures. This allowed separate determination of the 

components of the elastic magnetic scattering cross section parallel 

and perpendicular to the solenoid guide field. This successful experiment creates opportunities for a variety of high efficiency polarized 

inelastic magnetic scattering experiments on MACS.

References

[1] J.A. Rodriguez-Rivera et al., Meas. Sci. Technol. 19, 034023 (2008).

[2] W.C. Chen et al., Journal of Physics: Conference Series 294, 

012003 (2011).

[3] Q. Ye et al., Physics Procedia 42, 206-212 (2013).

FIGURE 1: Top view of the MACS polarization analysis apparatus. The neutron 

beam enters from the top of the images, where the MACS pre-sample optics 

can be seen. The left photo shows the 3He cells mounted within the 3 mT 

solenoid; the polarizer cell is contained in the aluminum box. The right photo 

shows the same view with an aluminum “thimble” that provides a mounting 

interface for the cryostat and protects the cells.

1 National Institute of Standards and Technology, Gaithersburg, MD 20899

2 University of Maryland, College Park, MD 20742

3 Johns Hopkins University, Baltimore, MD 21218

4 Tohoku University, Sendai, Miyagi 980-8577 Japan

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 49ADVANCES IN MEASUREMENT
Advances in measuring time-resolved neutron 

scattering from flowing complex fluids

S. A. Rogers, M. A. Calabrese, and N. J. Wagner

S

oft materials can undergo time-dependent flows during their 

production, processing and transportation, as well as during use. 

The microstructure of soft materials may be significantly different 

under flow than that at rest. Such flow-induced changes in microstructure may be beneficial, such as reducing the viscosity during the 

pouring of liquid detergents or transporting fluids while drilling oil and 

gas wells, or detrimental, such as the degradation of product stability 

during shipping. Therefore, there is a fundamental need for accurate, 

time-resolved measurements of microstructure under flow to aid in 

understanding and controlling the properties of flowing complex fluids.

This report presents new methods for probing microstructural changes 

on the nanoscale during dynamic deformations using time-resolved 

small-angle neutron scattering (SANS). Traditional SANS methods 

provide the necessary structural information on relevant length scales, 

but are typically averaged in time. With increases in neutron flux on the 

SANS instruments at the NCNR and through developing more efficient 

and accurate algorithms for analyzing data from temporally-resolved 

SANS experiments, we can now uncover previously unknown dynamic 

behaviors of materials whose static and steady-state flow properties 

may have been well-understood for decades.

As an example of the new information accessible using time-resolved 

SANS, we explore the effects of branching on the flow properties of 

self-assembled micellar solutions. The issue of branching in polymer 

science is a significant and long-standing scientific and technological 

challenge and worm-like, or polymer-like micelles are often used as 

model systems for understanding this class of complex fluids. Time 

dependent flows, such as flow startup and large amplitude oscillatory shear (LAOS), have been proposed as methods to characterize 

branching in such systems. We recently developed SANS techniques 

involving transient flows for the purpose of linking microstructural 

transitions to the macroscopic flow behavior [1-6].

The branched micellar solutions of interest are composed of the mixed 

cationic and anionic surfactant cetyltrimethylammonium tosylate (CTAT) 

and sodium dodecyl benzene sulfonate (SDBS) with sodium tosylate 

(NaTos) added to induce branching [7]. Under shear flow, segmental 

alignment of the micelles is observed in the flow direction and is 

quantified here by the scalar alignment factor, Af, which varies from 

0 for isotropic to 1 for full alignment. Material behavior is especially 

interesting under LAOS deformations [2, 4], where temporal resolution 

of ≈ 100 ms can be achieved. 

Reported here is an example from our recent study of the alternating 

state of a branched WLM under LAOS (Fig. 1). Time stamping and 

triggering capabilities allow the alignment factor to be measured 

throughout the course of the applied oscillation [4]. A new analysis 

method that employs signal-processing techniques is applied to the 

neutron scattering data. We compare the values of Af obtained from 

the standard stroboscopic method using binning techniques in Fig. 1a, 

where 15 discrete points were collected per half period against the 

same data but analyzed using the new procedure shown in (b). This 

new analysis provides a nearly continuous curve (b) revealing fine 

details in the time evolution of Af (circled region) that closely mimic 

similar features observed in the rheology, overlaid in Fig 1(b). These 

microstructural changes are not evident in the data obtained using 

traditional binning (a). The method also decreases the total measurement time required to achieve a given level of precision as compared to 

binning methods. Ongoing and future work will use these techniques 

to quantify the effects of branching on WLM rheology and should 

find numerous applications in broader studies of the time-dependent 

behavior of complex fluids and soft materials.

References

[1] A. P. R. Eberle, L. Porcar, Curr. Opin. Colloid Int. Sci. 17 (1), 

33 (2012).

[2] S. A. Rogers, J. Kohlbrecher, M. P. Lettinga, Soft Matter 8 (30), 

7831 (2012).

[3] A. K. Gurnon et al., J.Vis. Exp. 1 (84), 51068 (2014).

[4] A. K. Gurnon, C. R. Lopez-Barron, A. P. R. Eberle, L. Porcar, 

N. J. Wagner, Soft Matter 10 (16), 2889 (2014).

[5] A. K. Gurnon, C. R. Lopez-Barron, M. J. Wasbrough, L. Porcar, 

N. J. Wagner, ACS Macro Letters 3 (3), 276 (2012).

[6] C. R. Lopez-Barron et al., Phys. Rev. E. 89 (4), 042301 (2014).

[7] B. A. Schubert, E. W. Kaler, N. J. Wagner, Langmuir 

19 (10), 4079 (2003).

FIGURE 1: The alignment factor for a branched WLM during part of a LAOS 

cycle: (a) measured using standard binning methods and (b) using the new 

methods. The new technique (b) resolves features (circled regions) that are 

not apparent in (a) but that are evident in the rheological stress measurements during LAOS at 0.2 rad/s and 225 strain amplitude.

Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716

50 NIST CENTER FOR NEUTRON RESEARCH ADVANCES IN MEASUREMENT
Development of a scintillator-based proportional counter 

for use in a chromatically analyzing neutron detector

N. C. Maliszewskyj,1 A. N. Osovizky,2,3 K. Pritchard,1 J. Ziegler,1 Y. Yehuda-Zada,4 E. Binkley,1 and C. F. Majkrzak1

T

he Chromatic Analysis 

Neutron Diffractometer 

or Reflectometer 

(CANDoR) will use a polychromatic incident beam of 

neutrons and an energy-analyzing bank of detectors to 

measure a complete reflectivity curve with only a few 

settings of the instrument. 

The detector bank consists 

of 30 independent channels, 

each consisting of an array of 

54 HOPG monochromator crystals oriented at takeoff angles that 

Bragg diffract neutrons of discrete energies from 5.1 meV (4 Å) to 

2.3 meV (6 Å) into corresponding neutron proportional counters. 

In order to maximize the number of energy analyzing channels 

and approximate the performance of a conventional 3He tube, the 

proportional counter must be exceedingly thin (≈ 1 mm), highly 

efficient (90 % for 3.3 meV (5 Å) neutrons), and have excellent 

gamma rejection (10-7).

The proportional counter under development uses 6LiF:ZnS (Ag) 

plastic scintillator [1] into which wavelength shifting (WLS) fibers 

have been embedded. The WLS fibers conduct the scintillation light 

out of the scattering plane to a silicon photomultiplier (SiPM) for 

readout (Figs. 1 and 2). Although the photon yield from a neutron 

capture is quite large (nominally 160,000 photons/neutron capture), 

a number of factors (opacity of ZnS to its own scintillation light, 

losses encountered in photon transport, photodetection efficiency 

of the photosensor) conspire to reduce the signal to a tiny level. 

Further, the inherent gamma sensitivity of the scintillator and 

thermally induced avalanches in the photosensor makes neutron 

discrimination a challenging proposition.

GEANT4 [2] simulations of this system have already pointed to a 

number of important optimizations to be made in the grain size and 

stoichiometry of 6LiF and ZnS in the scintillator and the arrangement 

and placement of the WLS fibers in the scintillator.

SEM imaging of scintillator material indicates that LiF and ZnS 

grains will tend to cluster, effectively creating larger grains than 

expected. Additionally, optical transmission measurements indicate 

that adding a 50 % greater proportion of binder to the scintillator 

composition can result in a nearly fourfold increase in the transmission of scintillation light through the scintillator. We are working 

actively with scintillator manufacturers to improve the light production and transmission within their product.

Although the ZnS in the scintillator is inherently sensitive to gamma 

rays, the duration of a burst of photons resulting from gamma 

capture is very short, on the order of 200 ns, while the duration of 

a burst of photons resulting from neutron capture is much longer, 

up to 2 μs or more. Pulse shape discrimination techniques may 

then be applied to discard the short, intense bursts resulting from 

gamma capture or thermally induced noise. By integrating the SiPM 

in “prompt” (200 ns) and “delayed” (200 ns to 2 μs) windows 

and setting thresholds on each it is possible to distinguish neutron 

capture events from other signals. In the current incarnation of the 

discriminator, a high speed analog-to-digital converter digitizes the 

raw signal from the SiPM, which is then processed by the firmware 

of a field programmable gate array. 

Currently, the 1 mm thick prototypes we have tested exhibit 90 % 

stopping power and 46 % neutron sensitivity at 3.3 meV. The pulse 

shape discrimination has resulted in excellent gamma rejection 

(2 × 10-7) measured using isotopic sources. Indications are that we 

may be able to increase the sensitivity by optimizing the scintillator 

composition and WLS configuration, actively cooling the SiPM, and 

tuning pulse shape discrimination parameters without compromising the geometry of the sensor. Next steps for the project 

include design and fabricating a prototype analyzer/detector array 

and scaling up the electronics to manage the signals from that 

array of 54 proportional counters.

References

[1] L. A. Wraight et al., Nucl. Instr. Meth. 33, 181 (1965).

[2] http://geant4.web.cern.ch/geant4

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

2 University of Maryland, College Park, MD 20742

3 ROTEM Industries Ltd, Beer Sheva, Israel

4 Ben Gurion University of the Negev, Beer Sheva, Israel

FIGURE 1: Neutron detection concept. FIGURE 2: A working prototype detector.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 51ADVANCES IN MEASUREMENT
SLDMOL: A tool for the structural characterization 

of thermally disordered membrane proteins

J. E. Curtis,1 H. Zhang,2 and H. Nanda1,3

Membrane proteins that interact peripherally or that dwell 

inside the lipid membranes of our cells are essential to many 

biological functions, from our ability to detect light, to our 

immune system recognizing the difference between native cells and 

foreign invaders, to the regulation of cell division which if unchecked 

can lead to cancer. X-ray and neutron reflectivity have emerged 

as powerful tools to study the complex molecular architecture of 

biological membranes, filling a pressing need for techniques that 

can characterize proteins in physiological lipid environments. Typical 

analysis methods of measured specular reflection provide a 1-D 

scattering length density (SLD) profile normal to the membrane 

plane that represents the distribution of protein atoms projected 

along the membrane normal vector. An important advancement 

in reflectivity analysis has been the integration of high-resolution 

structural data (e.g. from crystallography or NMR) with reflectivity 

to yield a 3-D view of how proteins are situated on the membrane 

[1]. However, for many proteins only partial structural information is 

available due to large flexible and disordered domains that are not 

resolved by traditional structural techniques. 

We recently developed the SLDMOL [2] program as a tool to 

facilitate the molecular interpretation of reflectivity results for 

full-length proteins consisting of structured as well as intrinsically 

disordered regions. SLDMOL can function either as a fitting utility 

to determine the ensemble of conformational states that best 

represents the reflectivity data or as a modeling utility to help design 

experiments based on selective deuteration and H2O/D2O contrast 

variation. In addition, the incorporation of SLDMOL as a module in 

the SASSIE [3] software package provides extended capabilities to 

generate ensembles of proteins structures and filter them based on 

various structural criteria. 

As an example of the fitting module we show its application to NR 

data collected for the retroviral assembly protein HIV-1 Gag bound to 

a solid supported tethered lipid membrane [4]. HIV-1 Gag is the single 

critical factor that drives the formation of new viral particles and is a 

highly flexible molecule consisting of three structured domains – the 

matrix (MA), capsid (CA) and nucleocapsid (NC) – joined by unstructured linkers. Fig. 1A shows the experimentally derived SLD profile 

and the weighted fit using SLDMOL. A density plot of all 100,000 

Gag configurations sampled as well as the best-fit subset is shown 

in Fig. 1B and 1C. The subset of configurations shown in Fig. 1C 

gave the best fit to the NR data by restricting SLDMOL to use only 

configurations with Rg < 70 Å. Trial deuteration schemes of Gag with 

either the MA or CA domains labeled can be modeled as shown in 

Fig. 1D. The significant difference in the SLD profiles suggests that 

such a measurement would be able to distinguish the location of 

each domain along the membrane normal direction.

The SLDMOL program has been developed to fit NR data with 

detailed 3-D molecular structures of proteins. SLDMOL can easily be 

used to refine reflectivity measurements of protein structure at any 

surface or interface. In addition, the modeling facilities of SLDMOL 

can perform virtual selective deuteration allowing for optimization 

of experiment design.

References

[1] H. Nanda et al., Biophys. J. 99, 2516 (2010).

[2] J. E. Curtis et al., Comput. Phys. Commun. 183, 382 (2012).

[3] J. E. Curtis et al., Comput. Phys. Commun. in press (2014).

[4] S. A. K. Datta et al., J. Mol. Biol. 406, 205 (2011).

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

2 California Institute of Technology, Pasadena, CA 91125

3 Carnegie Mellon University, Pittsburgh, PA 15213

FIGURE 1: Modeling HIV-1 Gag protein bound to a solid supported tethered 

bilayer. (A): NR experiments were used to determine the 1-D structure of 

the tethered bilayer (gray line) and the SLD profile of Gag on the membrane 

(blue circles). SASSIE was used to generate 100,000 independent structures of the Gag protein by varying the backbone dihedrals of the flexible 

amino acid regions. An average SLD profile using a Monte-Carlo optimization to weight the structures provided a best fit to the data (blue lines). 

(B) and (C): Overlay of the 3-D density distribution from the entire conformations ensemble of Gag (grey density) with a single extended protein 

structure (B) and with Gag conformations that best fit to the NR data (C), 

shown as green density. (D): Modeling deuteration schemes of a compact 

Gag structure with either the MA or CA domain labeled.

52 NIST CENTER FOR NEUTRON RESEARCH ADVANCES IN MEASUREMENT
The NCNR participated in an International Physical Protection 

Advisory Service (IPPAS) assessment in FY 2014. The IPPAS is a 

program within the IAEA (International Atomic Energy Agency). 

The IPPAS team reviews and compares security regulations and 

nuclear facility physical protection systems with international 

guidelines and best practices. The Nuclear Regulatory Commission 

and NIST requested the IPPAS assessment, and the NCNR agreed 

to host a site visit and security posture evaluation. Experts in 

nuclear facility security from eight member states of the IAEA 

visited the NCNR and found the facility met or exceeded NRC 

security requirements and international guidance.

A new project began this year within ROE to consider a possible 

design for a replacement of the NBSR. Planning continues to relicense the NBSR for another 20 years in 2029, but NCNR management is considering an eventual replacement of the NBSR. The new 

reactor would be designed to operate using low enriched uranium 

(LEU) fuel and be optimized for the production of cold neutrons.

Neutron Source Operations 

FIGURE 1: NCNR Director Rob Dimeo (left) participating in the IPPAS kick-off 

meeting along with William Ostendorff (NRC) and Denis Flory (IAEA).

T

he NCNR neutron source, the 20 MW test reactor (NBSR), 

operated for 218 days in FY 2014 with a reliability of 93 %. 

Reliability, as defined by the NCNR, is the ability to deliver 

neutrons and experimental access for the scientific users on the 

day scheduled. The NCNR has historically started the facility on 

schedule and has typically only missed a few days per year of 

the scheduled experimental cycles due to equipment or other 

problems. The government-wide shutdown did not have a direct 

impact on facility operation for experiments because the experimental cycle 613 ended on September 30, 2013 and the government shutdown began the next day. Unfortunately, non-essential 

reactor maintenance had to be postponed until October 16, 

which delayed the start of the normal two week maintenance 

period that must occur between experimental cycles. During the 

two-week maintenance period, a mechanical problem with the 

NBSR fuel transfer system prevented loading sufficient reactor 

fuel for a full 39-day experimental cycle. After a full safety review 

to consider the off-normal fuel loading, the NBSR was started 

on October 28 to permit user experiments and to repair the fuel 

transfer system during the next shutdown period. Repairs to the 

fuel transfer system were completed in late December, which 

allowed the NBSR to return to a normal schedule, by February. 

During 2014, Reactor Operations and Engineering (ROE) continued 

the NBSR life extension program by replacing or upgrading older 

equipment and systems to position the facility to receive an additional 20-year facility license in 2029. One such system was the 

reactor emergency electrical power systems. The NCNR and NIST 

are supplied by fairly reliable commercial power, but the NBSR 

requires backup electrical systems in the event off-site power is 

lost. Large batteries supply one portion of that backup system 

and diesel generators supply another portion of the system. 

The designed reliability and redundancy (two independent battery 

systems and two independent diesel generators) assure the NBSR 

critical systems will continue to operate during an unplanned 

shutdown caused by a loss of site power.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 53NEUTRON SOURCE OPERATIONS
Facility Development

Two major relocation projects were completed within the Facility’s primary Instrument Development program. 

First, the Neutron Spin Echo instrument has been relocated 

from NG-5 to the recently installed NG-A guide. Its location in 

the new guide hall provides a magnetically quieter experimental 

area; thus the instrument is now less susceptible to stray magnetic 

fields. With the move came major investment, upgrading to all 

new power supplies and a new polarizing cavity, improving both 

the reliability and sensitivity of the instrument. The instrument has 

also migrated to the Facility’s new data acquisition and instrument control software, NICE, which marks a significant step in 

the roll-out of this new code. Following a rigorous commissioning 

program for the new power supplies the instrument is now back 

in the user program with substantial gains in performance. 

Second, one of the 30 m SANS instruments has also been moved 

from its long-standing location on NG-3 and reinstalled in the new 

guide hall. The instrument is now situated on NG-Bupper, next to the 

10 m SANS, on the second of two low-divergence 50 mm × 50 mm 

cross-section guides on the new guide network dedicated to the 

SANS program. Following detailed planning and capitalizing on an 

extended early-Spring shutdown required for building infrastructure 

work, the move was completed with minimal impact to the SANS 

user program. The move has also resulted in significant performance gains for the instrument by virtue of the new guide and 

from the opportunity to re-align guides in the pre-sample vessel.

The 30 m SANS relocation marked the first step toward installation of the 40 m very Small Angle Neutron Scattering (vSANS) 

instrument at the now vacant NG-3 position. vSANS is one of two 

new neutron scattering instruments currently under construction 

at the Facility and will be a highly versatile and unique instrument offering an extended Q-range (2.0 x 10-4 < Q(Å-1) < 0.7) 

thus bridging the gap between conventional SANS and uSANS 

instruments. The design includes both multiple converging pinhole 

and multiple converging slit geometries and is optimized to take 

advantage of the current large neutron guide at NG-3, thus 

offering appropriate intensity for the measurements. A control 

network has now been established at NG-3 for alignment of 

the vSANS pre-sample flight path components. The velocity 

selector bunker and pre-sample vessels are on site and ready 

for pre-assembly and installation in the coming months. 

The second of NCNR’s new instruments under development is 

the white-beam reflectometer CANDoR. The instrument will 

occupy the NG-1 beam line and all pre-sample components have 

completed designs and are now out for manufacture. CANDoR 

promises major performance gains by utilizing a polychromatic 

incident beam of neutrons and an energy analyzing bank of 

detectors to measure a complete reflectivity curve with only a 

few settings of the spectrometer. Accordingly the Facility has an 

on-going scintillator detector development program dedicated 

to the CANDoR project. Recent developments in this program 

are described in a highlight earlier in this report. 

Neutron Spin Filters

The NCNR supports an active program, operated in collaboration 

with the Physical Measurement Laboratory at NIST, to provide and 

develop 3He neutron spin filters (NSFs) to support measurement 

capabilities using polarized neutrons. Polarized beam experiments 

are routinely carried out on the BT-7 thermal neutron triple-axis 

spectrometer and the small-angle neutron scattering instruments. 

During the past year, the NCNR’s spin filter program serviced 

29 user experiments, for a total of 104 days of beam time and 

79 bar-liters of polarized 3He gas. 

FIGURE 1: The Neutron Spin Echo spectrometer in its new location on NG-A 

in the guide hall extension. (Photo credit: Yiming Qiu)

FIGURE 2: Riggers maneuver the 30 m SANS detector vessel from NG-3 to its 

new location on NG-Bu in the guide hall extension. (Photo credit: Yiming Qiu)

54 NIST CENTER FOR NEUTRON RESEARCH FACILITY DEVELOPMENT
3He gas is polarized by spin-exchange optical pumping (SEOP), 

in which alkali-metal atoms are polarized by optical pumping 

and the resulting electronic polarization is transferred to 3He 

nuclei in spin-exchange collisions. Alkali vapor is produced by 

heating a boron-free aluminosilicate glass cell containing 3He, 

N2 and a Rb-K mixture metal to 220 °C and illuminating it with 

near-infrared laser light provided by two or three 100 W diode 

lasers. Each laser is spectrally narrowed with feedback from a 

chirped volume holographic grating (VHG). The goal, as always, 

is to continually improve polarized neutronic performance 

and recent achievements include: fabrication of several large 

high-pressure cells to meet demands of polarized inelastic experiments on BT-7 with an energy transfer up to 35 meV; fabrication 

and operation of a large diameter SANS cell that allows users 

to access magnetic features at higher momentum transfer Q;

successful operation of wide-angle cells for use on the Multi-Axis 

Crystal Spectrometer (MACS). The success of the wide-angle cells 

is also highlighted earlier in this report.

Refurbishment of the new 3He spin filter laboratory has finally 

been completed and this has enabled an additional SEOP system 

(SEOP C) to be implemented in the new lab. Motivated by the 

need to polarize wide-angle analyzer cells for MACS, the new 

system is equipped with a larger oven and three diode lasers. 

The system has been commissioned and the higher laser power 

now enables full polarization of most large-volume cells within 

a day. This new capability permits more efficient support (about 

50 % faster) and better performance of polarized beam experiments. The two existing SEOP systems (SEOP A and SEOP B) will 

be upgraded to offer a similar capability in the near future.

Data Acquisition Software

The New Instrument Control Environment software package 

(NICE) has been deployed across the suite of reflectometers 

– MAGIK, PBR, and most recently on the horizontal sample 

geometry reflectometer on NG-7. A significant project milestone 

has been achieved with the roll out of NICE on the neutron spin 

echo spectrometer to meet the complex control requirements of 

the spectrometer’s new power supply system that could not be 

operated by the legacy software system deployed previously. 

NICE is a Java-based package that incorporates a highly versatile 

scripting capability to enable end user adaptations to be coded 

under all the major scientific programing languages. Beta-testing 

of the new code has started on 10 m SANS and on BT-4 in its 

triple-axis spectrometer configuration.

Data Analysis Software

The Facility is a contributor to the international SANS team 

working to develop the DANSE/SASview software package. 

SASView utilizes the bumps fitting engine that now includes an 

entropy calculator as a new feature and general developments 

to the package include uncertainly analysis and support for 

general-purpose computing on graphics processing units.

Development activity continues on the reflectometry analysis 

package Refl1d that originated from the DANSE (Distributed Data 

Analysis for Neutron Scattering Experiments) project. This package 

is used by many of our external users to fit their more complicated 

reflectometry models and a rudimentary graphical user interface 

has been added to facilitate the input and building of these models. 

Facility users of the inelastic neutron scattering instruments at the 

NCNR require an effective means of quickly reducing, visualizing 

and analyzing their experiment data. For the last dozen years the 

Data Analysis and Visualization Environment (DAVE) software 

suite has served as the primary platform through which a large 

toolset of programs have been compiled and distributed freely 

to users. The suite is actively maintained in response to feedback 

from the user community, updated regularly with new functionality and modified as needed to accommodate improvements to 

neutron scattering instrumentation.

One component that has recently received a major overhaul is the 

data reduction module for the Spin Polarized Inelastic Neutron 

Spectrometer (SPINS). This instrument can be operated in several 

modes. The conventional triple axis mode using a single detector 

is already handled in the generic Triple Axis Reduction component 

in DAVE. The new module – SPINS PSD Reduction – handles data 

taken using the flat but vertically focused multi-crystal analyzer 

and with the two-dimensional position sensitive detector (PSD). 

In this mode, the 20 cm x 25 cm PSD detector captures data 

with 256 individual pixels horizontally while integrating along the 

vertical direction. Multiple datasets can be reduced simultaneously 

and the resulting volumetric data can then be manipulated 

(2D planar slices and 1D cuts) further using Mslice and analyzed 

using the Peak Fitting module, PAN. The PSD on SPINS is 

currently underutilized, in part due to a lack of suitable software 

for interpreting the data. It is hoped that with this addition to 

DAVE, more users will capitalize on the increased count rate 

available when SPINS is operated in this mode.

FIGURE 3: The main interface for SPINS PSD Reduction in DAVE. 

The display window shows a single dataset portraying the intensity as 

a function of wavevector transfer in the scattering plane defined by the 

sample orientation vectors.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 55FACILITY DEVELOPMENT
Serving the Science and Technology Community

T

he mission of the NIST Center for Neutron Research is to 

assure the availability of neutron measurement capabilities 

to meet the needs of U.S. researchers from industry, 

academia and 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 beam 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 (The Johns Hopkins University) 

• Leslie Butler (Louisiana State University)

• Kushol Gupta (University of Pennsylvania) 

• Hye-Jung Kang (Clemson University)

• Ramanan Krishnamoorti (University of Houston)

• Valery Kiryukhin (Rutgers University) 

• Jennifer Lee (National Institutes of Health)

• Raul Lobo (University of Delaware)

• Janna Maranas (The Pennsylvania State University) 

• Steven May (Drexel University)

• Alan Nakatani (Dow Chemical Company)

• Lilo Pozzo (University of Washington)

• Stephan Rosenkranz (Argonne National Laboratory)

• Gila Stein (University of Houston)

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.

Collaboration with NIST

Some time on all instruments is available to NIST staff in support 

of our mission. This time is used to work on NIST research needs, 

instrument development, and promoting the widespread use 

of neutron measurements in important research areas, particularly by new users. As a result of these objectives, a significant 

fraction of the time available to NIST staff is used collaboratively 

by external users, who often take the lead in the research. Access 

through such collaborations is managed through written beam 

time requests. In contrast to proposals, beam time requests are 

reviewed and approved internally by NCNR staff. We encourage 

users interested in exploring collaborative research opportunities 

to contact an appropriate NCNR staff member.

Research Participation and Productivity

The NCNR continued its strong record of serving the U.S. 

research community this year. Over the 2014 reporting year, 

2271 research participants benefited from use of the NCNR. 

(Research participants include users who come to the NCNR to use 

the facility as well as active collaborators, including co-proposers 

of approved experiments, and co-authors of publications 

resulting from work performed at the NCNR.) As the number 

of participants has grown, the number of publications per year 

has increased in proportion. The quality of the publications has 

been maintained at a very high level. The trend of the past few 

56 NIST CENTER FOR NEUTRON RESEARCH SERVING THE SCIENCE AND TECHNOLOGY COMMUNITY
years, however, suggests that the number of participants and 

publications is beginning to saturate, as one might expect as the 

capacity of the facility is reached. Completion of instruments 

associated with the Expansion Initiative that has taken place over 

the past few years promises increasing activity and productivity.

2014 NCNR Proposal Program

In response to the last two calls for proposals for instrument 

time, we received 667 proposals, of which 386 were approved 

and received beam time. The oversubscription, i.e., the ratio of 

days requested on all proposals to the days available, was 2.0 

on average, but as high as 3.1 for specific instruments. Proposal 

demand has grown constantly since the NCNR first began 

accepting proposals in 1991, and has doubled in the past decade. 

The following table shows the data for several instrument classes. 

Instrument class Proposals

Days 

requested

Days 

allocated

SANS and USANS 263 964 461

Reflectometers 97 583 348

Spectrometers 257 1701 761

Diffraction 20 77 56

Imaging 30 146 100

Total 667 3471 1726

Users Group

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. The 

current members of the NUG Executive Committee are Despina 

Louca (University of Virginia, chair), Kate Gurnon (University of 

Delaware, student/postdoc member), John Katsaras (Oak Ridge 

National Laboratory), Michael Mackay (University of Delaware), 

Alan Nakatani (Dow Chemical), Megan Robertson (University of 

Houston), and Dale Schaefer (University of Cincinnati). 

Panel of Assessment

The major organizational components of NIST are evaluated 

annually for quality and effectiveness by the National Research 

Council (NRC), the principal operating agency of both the 

National Academy of Sciences and the National Academy of 

Engineering. A panel appointed by the NRC last reported on 

the NIST Center of Neutron Research in July 2013. The findings 

are summarized in a document that may be viewed online at 

http://www.nist.gov/director/nrc/upload/ncnr-final-report-2013.pdf. 

The panel members included Paul Fleury (Yale University), Peter 

Green (University of Michigan), Laura Greene (University of 

Illinois), Andrew Harrison (Institut Laue-Langevin), Alan Hurd (U.S. 

Department of State), Dale Klein (University of Texas), Wade Konze 

(Dow Chemical Company), Roger Alan Leach (DuPont Central 

Research and Development), Brian Maple (University of California, 

San Diego), V. Adrian Parseghian (University of Masssachusetts), 

and David Weitz (Harvard University).

The Center for High Resolution Neutron 

Scattering (CHRNS)

CHRNS is a national user facility that is jointly funded by the 

National Science Foundation and the NCNR. Its primary goal 

is to maximize access to state-of-the-art neutron scattering 

instrumentation for the research community. It operates six 

neutron scattering instruments at the NCNR, enabling users from 

around the nation to observe dynamical phenomena involving 

energies from ≈ 30 neV 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 61 

of this report.

Partnerships for Specific Instruments

NG-7 SANS Consortium

A consortium that includes NIST, the ExxonMobil Research 

and Engineering Company, and the Industrial Partnership for 

Research in Interfacial and Materials Engineering (IPRIME) led by 

the University of Minnesota, operates, maintains, and conducts 

research at the NG-7 30 m SANS instrument. The consortium uses 

57 % of the beam time on this instrument, with the remaining 

43 % allocated to the general scientific community through the 

NCNR’s proposal system. Consortium members conduct independent research programs primarily in the area of large-scale 

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. 

The nSoft Consortium

Formed in August 2012, the nSoft Consortium allows member 

companies to participate with NIST in the development of 

advanced measurements of materials and manufacturing 

processes, and develop their own expertise in state-of-the-art 

FIGURE 1: Research participants at the NCNR 1986 - 2014.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 57SERVING THE SCIENCE AND TECHNOLOGY COMMUNITY
measurement technologies to include in their analytical research 

programs. nSoft develops new neutron-based measurement 

science for manufacturers of soft materials including plastics, 

composites, protein solutions, surfactants, and colloidal fluids. 

Members receive access to leading expertise and training support 

in neutron technology and soft materials science at NIST. Contact: 

Ron Jones, nSoft Director, rljones@nist.gov, 301-975-4624.

NIST / General Motors – Neutron Imaging

An ongoing partnership and collaboration between General 

Motors and NIST that now includes Honda Motors through GM’s 

partnership with Honda continues to yield exciting results using 

neutron imaging. Neutron imaging has been employed to visualize 

the operation of fuel cells for automotive vehicle applications. 

Neutron imaging is an ideal method for visualizing hydrogen, 

the fuel of electric vehicle engines. These unique, fundamental 

measurements provide valuable material characterizations that will 

help improve the performance, increase the reliability, and reduce 

the time to market introduction of the next generation electric car 

engines. 25 % of the time on the BT-2 Neutron Imaging Facility 

is made available to the general scientific community through 

peer-reviewed proposals.

Interagency Collaborations

The Smithsonian Institution’s Nuclear Laboratory for 

Archaeological Research is part of the Anthropology Department 

at the National Museum of Natural History. It has had a productive 

35 year partnership with the NCNR, during which time it has 

chemically analyzed over 43,100 archaeological artifacts by 

Instrumental Neutron Activation Analysis (INAA), drawing 

extensively on the collections of the Smithsonian, as well as on 

those of many other institutions in this country and abroad. 

Such chemical analyses provide a means of linking these diverse 

collections together in order to study continuity and change 

involved in the production of ceramic and other artifacts.

The Center for Food Safety and Applied Nutrition, U.S. Food and 

Drug Administration (FDA), maintains laboratory facilities at the 

NCNR providing agency-wide analytical support for food safety 

and food defense programs. Neutron activation and low-level 

gamma-ray detection techniques yield multi-element and radiological information about foods and related materials and provide 

a metrological foundation for FDA’s field investigations and for 

radiological emergency response planning. Current studies include 

development and validation of swordfish and cocoa powder 

in-house reference materials, and emergency response/recovery 

work focuses on measuring cesium levels in soil to study cesium 

uptake behavior into food products.

58 NIST CENTER FOR NEUTRON RESEARCH SERVING THE SCIENCE AND TECHNOLOGY COMMUNITY
Neutron Workshop

T

he instruments currently under development at the NCNR 

are nearing completion so planning has begun for the next 

decade of instrument development. As part of this process, 

NIST and the University of Maryland co-hosted a workshop on 

“Neutron Measurements for Materials Design & Characterization” 

held on August 21st and 22nd, 2014 at the Bolger Center in 

Potomac, Maryland. More than 100 attendees employed their 

expertise and experience to help map out the future directions 

for NCNR instrument development. 

This workshop largely built upon the success of the “NCNR 

Expansion Initiative Workshop” held in July of 2006. Based in 

part upon the input from the attendees, the NCNR initiated 

an instrument development plan that addressed the identified 

research needs of the scientific community at that time. The NCNR 

will shortly commission the last two instruments identified in this 

plan: vSANS, a new small-angle neutron scattering instrument 

that will permit measurements over a very broad range of length 

scales; and CANDoR, a broad bandwidth reflectometer using 

energy dispersive detectors enabling high-throughput. After 

commissioning these instruments there will still be two vacant end 

positions and possibly two side positions available for additional 

instruments. The attendees of the recent August workshop were 

thus tasked with the goals of determining:

• New research opportunities that can be addressed by new 

capabilities in the NCNR Expansion.

• Neutron measurement capabilities that would open new 

research opportunities.

To achieve these targets, the attendees were divided into nine 

breakout groups based on their scientific expertise. Each group 

provided an oral report at the end of the workshop and a written 

report shortly thereafter. Rob Briber from the University of 

Maryland and Collin Broholm from Johns Hopkins University then 

condensed the various contributions into an executive summary.

This report highlighted the important contributions that neutron 

scattering has played and continues to play in the development 

and characterization of new materials that enhance our quality of 

life. It also called for fully instrumenting the NCNR. To quote the 

Executive Summary:

With the development of vSANS and CANDoR, the promise of 

a new D2 cold source, improvements in many other instruments 

and new detector technologies, the NCNR will remain one of 

a small number of leading neutron scattering facilities in the 

world. There are still open end positions available (one served 

with thermal neutrons and one with cold neutrons). These 

FIGURE 1: Attendees at the August workshop listen attentively to one of the plenary speakers.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 59NEUTRON WORKSHOP
positions are quite valuable and new instruments should be 

built at each after a careful evaluation of proposed instrumentation is carried out.

The summary then highlighted several possible choices for instrumenting these open positions including a high throughput powder 

diffractometer, a new cold triple axis instrument employing the 

revolutionary detector developed for CANDoR, a new SANS 

instrument for biological systems, and a substantially upgraded 

neutron spin echo instrument. 

In addition to the improvement in detector technology that will 

be employed on CANDoR mentioned above, the report also called 

for concerted efforts: 1) to develop new neutron optics (focusing 

optics and Wolter optics) to provide high flux neutron beams for 

all instruments; 2) to continue developing neutron polarization 

techniques through the use of spin filters based on polarized 3He 

and to expand their use to more instruments; 3) to engage the 

scientific community in identifying and developing new sample 

environment systems that extend the variety and range of the 

fields that can be applied to samples while performing neutron 

measurements; and to 4) continue to improve the quality of the 

scientific support infrastructure in terms of lab space for sample 

preparation, ancillary characterization tools, and high quality data 

collection, visualization, and analysis software. 

The participants at the workshop clearly believe that the NCNR is 

poised to continue its record of scientific excellence well into the 

future stating in the conclusion of the Executive Summary:

Through the implementation of the on-going and planned 

upgrades to the facility and new instrumentation and by 

following the science outlined by the participants at this 

workshop, the NCNR will remain a world leader in neutron 

science for the next decade and beyond.

FIGURE 2: Members of the Nanostructured Hard Materials breakout group take a brief break from their deliberations.

60 NIST CENTER FOR NEUTRON RESEARCH NEUTRON WORKSHOP
T

he Center for High Resolution Neutron Scattering is a 

national user facility that is jointly funded by the National 

Science Foundation through its Division of Materials 

Research (grant number DMR-0944772) and by the NCNR. The 

primary purpose of this partnership is to maximize access to stateof-the-art neutron scattering instrumentation for the research 

community using the NCNR’s proposal system. Proposals to use 

the CHRNS instruments are critically reviewed on the basis of 

scientific merit and/or technological importance. The core mission 

of CHRNS is fourfold: (i) to develop and operate neutron scattering instrumentation, with broad application in materials research, 

for use by the general scientific community; (ii) to promote the 

effective use of the CHRNS instruments by having an identifiable 

staff whose primary function is to assist users; (iii) to conduct 

research that advances the capabilities and utilization of CHRNS 

facilities; and (iv) to contribute to the development of human 

resources through educational and outreach efforts. 

Scattering Instruments and Research

During FY 2014, CHRNS supported operation of the following 

instruments: the NG-3 30 m Small Angle Neutron Scattering 

(SANS) instrument, the Ultra-Small Angle Neutron Scattering 

(USANS) instrument, the Multi- Angle Crystal Spectrometer 

(MACS), the Disk Chopper Spectrometer (DCS), the High Flux 

Backscattering Spectrometer (HFBS), and the Neutron SpinEcho (NSE) spectrometer. The small angle scattering instruments 

together provide structural information over length scales from 

≈ 1 nm to ≈ 10 μm. The spectrometers collectively yield dynamical information over time scales from ≈ 3 x 10-14 s to ≈ 10-7 s 

(energy scales from ≈ 100 meV to ≈ 30 neV). CHRNS users also 

have access to full polarization-analyzed SANS capabilities via 

the new double-V SANS polarizer (99 % polarization efficiency) 

used in conjunction with a radio frequency spin flipper and 3He 

spin analyzer cells. These wide ranges of capabilities 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 31), 219 proposals 

requested CHRNS instruments, and 125 of these proposals 

received beam time. Of the 1079 days requested for the CHRNS 

instruments, 551 were awarded. Approximately two-thirds of 

all proposals received by the NCNR request CHRNS instruments. 

Publications resulting from experiments on these instruments over 

the current one-year period are identified in the “Publications” 

section (p. 66). This report also contains several highlights of 

CHRNS publications. See the labeled highlights in the table of 

contents.

Scientific Support Services

CHRNS offers scientific support to our users in two critical areas: 

sample environment and chemical laboratories.

The laboratory staff ensures that users in our six user laboratories 

have the equipment and supplies they need for a successful 

experiment. Moreover, they advise and assist users with sample 

preparation. During the past year, Stacey Cochiara replaced 

Kim Tomasi as the primary laboratory support staff. Stacey is 

continuing the CHRNS tradition of working closely with our 

users to provide them with the items they need so that they can 

concentrate on their science rather than instrumental details. 

The majority of CHRNS users apply external fields to their 

samples. The CHRNS Sample Environment team operates and 

maintains the equipment needed to make neutron measurements under conditions of temperature, pressure, magnetic and 

electric fields, and fluid flow. This year we commissioned two 

high-temperature closed-cycle refrigerators (CCR). The new CCRs’ 

temperature range extends from 15 K to 800 K, a wider range 

than previously available. 

FIGURE 1: Sample Environment Team member Tanya Dax prepares one of 

the closed cycle refrigerators for a user.

The Center for High Resolution Neutron Scattering 

(CHRNS) 

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 61T H E C E N T E R F O R H I G H R E S O L U T I O N N E U T R O N S C A T T E R I N G ( C H R N S ) 
Education and Outreach

This year the Center for High Resolution Neutron Scattering sponsored a variety of educational programs and activities tailored to 

specific age groups and professions. The annual summer school, 

held on July 13 - 18, 2014 was entitled “Methods and Applications 

of Small Angle Neutron Scattering and Neutron Reflectometry.” 

Thirty-five graduate and postdoctoral students from 29 universities participated in the school. Course evaluations and student 

feedback was very positive. 

As part of its education and outreach effort, CHRNS offers 

to university-based research groups with BTAC-approved 

proposals the opportunity to request travel support for an 

additional graduate student to participate in the experiment. 

Announcements of this program are sent to all of the university 

groups whose experimental proposals receive beam time from 

the BTAC. The program is also advertised on the NCNR’s 

website at http://www.ncnr.nist.gov/outreach.html. 

For more than a year we have been fortunate to host Prof. 

Kimani Stancil at the NCNR via a cooperative research agreement 

with Howard University in Washington, DC. Prof. Stancil and his 

students spend their summers at the NCNR performing research on 

the structure of soft matter using SANS. They continue to work on 

these projects during the school year, as time permits. The success 

of this arrangement lays the groundwork for similar arrangements 

with professors from other minority serving institutions. 

As in previous years, CHRNS participated in NIST’s Summer 

Undergraduate Research Fellowship (SURF) program. In 2014 

CHRNS hosted 15 SURF students. The students made considerable contributions on research projects such as rheological flow 

of micelles and surfactants, magnetic ground state determination for thin-film industrial sensors, dynamics of methanol/water 

mixtures, gas adsorption in metal-organic frameworks, enhanced 

fitting engines for diffraction data refinement, and reactor control 

systems development. Students presented the results of their 

research at the NIST SURF colloquium in early August 2014.

FIGURE 2: Participants and instructors in the NCNR 2014 Summer School “Methods and Applications of Small Angle Neutron Scattering and Neutron Reflectometry.” 

FIGURE 3: The 2014 SURF students with NCNR director Rob Dimeo (right), CHRNS director Dan Neumann (second from left), and chief of reactor operations 

Sean O’Kelly (left). 

62 NIST CENTER FOR NEUTRON RESEARCH T H E C E N T E R F O R H I G H R E S O L U T I O N N E U T R O N S C A T T E R I N G ( C H R N S ) 
Elementary, Middle, and High School Activities

The Summer High School Intern Program (SHIP) has been a very 

successful, competitive NIST-wide program for students who are 

interested in performing scientific research during the summer. 

This year, the NCNR staff hosted seven high school interns. 

The students participated on research projects such as developing methodologies for imaging thin-film batteries and fuel 

cells, Monte Carlo simulation for anti-neutrino detector shielding, 

web-based data fitting, and model analysis of two-dimensional 

SANS data. The results of the students’ summer investigations 

were highlighted in a NIST-wide poster session in early August, 

as well as in an oral symposium at the NCNR. The success of the 

high school students is exemplified by the accomplishments of 

one of the 2013 SHIP students, André Guzmán from Poolesville 

High School, who received 2nd place in high school physics at 

the Montgomery County Science Fair as well as the Robert H. 

Herndon Award that is intended to encourage minority students 

to pursue careers in science and engineering.

The NCNR initiated a Research Experiences for Teachers (RET) 

program in the summer of 2010. Northwest High School teacher 

Richard Menendez (Montgomery County, MD) was selected 

for the program for the summer of 2014. He collaborated with 

NCNR’s Chris Bertrand and Koty McAllister, an undergraduate 

from the University of Delaware, on a project involving reversible 

colloidal aggregation in a near critical binary mixture.

The annual Summer Institute for Middle School Science Teachers 

brings middle school science teachers from across the United 

States (and for the first time, from American Samoa) to NIST for 

two weeks. Each year, CHRNS hosts the teachers for a one-day 

introduction to neutron scattering. Having toured the neutron 

guide hall and having seen several neutron instruments, the 

teachers learn about the types of experiments performed at 

the NCNR. To bring home projects suitable for middle school 

students, teachers then learn how to grow crystals of alum 

(hydrated aluminum potassium sulfate). Throughout the day 

and at lunchtime, the teachers have the opportunity to interact 

with NCNR staff. 

CHRNS also hosts a variety of other educational activities for K-12 

students including tours (more than 20 in the last year), “Take 

Your Daughters and Sons to Work Day”, and “Adventures in 

Science”, a hands-on science program for middle school students.

FIGURE 4: The 2014 high school interns with CHRNS director Dan Neumann (fourth from right).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 63T H E C E N T E R F O R H I G H R E S O L U T I O N N E U T R O N S C A T T E R I N G ( C H R N S ) 
Prof. Peter Dowding from Infineum UK 

Limited has received the Inspiration and 

Industry Award for 2014 from the Royal 

Society of Chemistry, “For his contribution to 

enthusing university students about research 

and colloid science.” Peter is a frequent 

NCNR user.

Tyrel M. McQueen Assistant Professor of 

Chemistry, Johns Hopkins University has been 

awarded a Cottrell Scholar Award from the 

Research Corporation for Science Advancement 

for his research “Superconductivity: From 

Discovery to Rational Design.” Tyrel often 

uses the NCNR facility for his work.

Kate Gurnon won a poster session award

at the 9th Annual European Rheology 

Conference, April 2014, held in Karlsruhe, 

Germany for her poster titled: “Spatiotemporal 

stress and microstructure evolution in dynami-

cally sheared wormlike micellar solutions using 

rheo- and flow-SANS.”

At the ACNS meeting in Knoxville, TN, June 

2014, Doug Godfrin won an ACNS student 

prize for his poster entitled: “Scattering study 

of reversible cluster formation in concentrated 

monoclonal antibody formulations” Doug is a 

graduate student at the University of Delaware 

stationed at the NCNR.

Thomas H. Epps, III of the University of 

Delaware received Sigma Xi’s Young 

Investigator Award for 2014 at their Annual 

Meeting held in Arizona, November 2014. He 

is the Thomas and Kipp Gutshall Associate 

Professor of Chemical and Biomolecular 

Engineering with a joint appointment in 

Materials Science. Thomas was recognized for 

his growing influence in the field of polymer 

physics where he designs, synthesizes, and 

characterizes new polymeric materials. 

Thomas has been a frequent NCNR facility 

user during his research.

Chetan Dital of Boston College received the 

2013-2014 Outstanding Dissertation in 

Magnetism Award from the APS Topical 

Group on Magnetism and its Applications 

(GMAG) for his dissertation: “Electronic Phase 

Separation and Magnetic Phase Behavior in the 

Ru-doped Spin-Orbit Mott Insulator Sr

3Ir2

O

7.” 

These awards recognize students who have 

conducted outstanding research leading to 

their dissertation.

Kate Ross of the NCNR has been awarded 

the 2014 NSSA Prize for Outstanding 

Student Research by the Neutron Scattering 

Society of America. Kate was recognized 

“For seminal neutron scattering studies of 

exotic ground states, ground state selection,

and spin excitations in XY pyrochlore magnets.”

Sushil Satija of the NCNR has been named 

as an NSSA Fellow for 2014 for “significant 

contributions to the advancement of the 

understanding of the physics of polymers at 

surfaces and interfaces through the develop-

ment and innovative application of neutron 

reflectometry.”

The NCNR’s Jeffrey Lynn has been listed 

as one of the “World’s Most Influential 

Scientific Minds” by Thomson Reuters, the 

publisher of the Web of Science. This recog-

nition is based on Thomson Reuters’ analysis 

of citations over the decade 2002-2012. Jeff is 

one of 144 scientists listed in the category of 

Physics. In addition, more than 40 of the scien-

tists on the various lists have participated in 

research at the NCNR over the past five years.

Jeff Lynn has also been awarded the 2014 

NSSA Sustained Research Prize by the 

Neutron Scattering Society of America. 

The award recognizes his “seminal studies 

of the colossal magneto-resistance effect 

and profound contributions to our under-

standing of the interplay of magnetism 

and superconductivity.”

2014 Awards 

64 NIST CENTER FOR NEUTRON RESEARCH 2 0 1 4 A W A R D S 
Wan Si Tang of the NCNR won a 

student poster award for her poster 

titled: “Altering the Structural Properties 

of A2B12H12 Compounds via Cation and 

Anion Modifications” presented at the 14th 

International Symposium on Metal-Hydrogen 

Systems held in Manchester, UK, in July 2014.

NCNR’s Daniel Hughes received the NIST 

Bronze Medal in December 2013. Dan 

was recognized “For outstanding oversight 

and coordination of all operational activities 

associated with the facility outage during 

the NCNR expansion project.”

A NIST Bronze Medal was awarded to the 

NCNR’s Paul Liposky in December 2013. 

Paul was recognized “For his innovative design 

and management of the NIST reactor spent-fuel 

storage pool refurbishment project.”

NCNR’s Rachel Pollock received the award for 

“Most Outstanding Poster” in the category 

of Materials for her poster titled “Kinetic 

Trapping of D2 in Mil-53(Al) Observed Using 

Neutron Scattering” at the annual Sigma Xi 

Post-doc poster presentation.

Andrew Yue of NIST’s Radiation Physics 

Division received the award for “Most 

Outstanding Poster” in the category 

of Physics for his poster titled “Improved 

Determination of the Neutron Lifetime” at the 

annual Sigma Xi Post-doc poster presentation.

Charles Majkrzak of the NCNR has received 

the Allen V. Astin Award. The award citation 

(in part) recognizes Chuck for “his numerous 

and seminal contributions to the measurement 

science and applications of neutron reflectivity. 

He has pioneered the exploration of many 

issues in “interface” science using this powerful 

technique, which has driven enormous 

advances in a huge range of scientific and 

technological areas.” The Allen V. Astin 

Measurement Science Award, first presented in 

1984, is granted for outstanding achievement 

in the advancement of measurement science or 

in the delivery of measurement services. 

NCNR’s Yun Liu received the 2014 NISTSigma Xi Katharine B. Gebbie Young 

Investigator Award. Yun is being recognized 

“For the discovery of dynamic cluster ordering 

in complex colloidal systems.”

Rana Ashkar of the NCNR and the University 

of Maryland has been selected as the winner 

of the Esther L. Kinsley Ph.D. Dissertation 

Award for 2013-2014 for her dissertation, 

“Dynamical Theory Applications to Neutron 

Scattering from Periodic Nanostructures” This 

is the highest honor for research that Indiana 

University bestows upon its graduate students.

The NCNR’s Shannon Watson won the best 

poster award at the Polarized Neutrons for 

Condensed Matter Investigations conference. 

Her poster was titled “Magnetostatic cavity 

advancements for 3He spin filters at the NCNR.” 

The conference was held in September 2014 

in Sydney, Australia.

The Samuel Wesley Stratton Award has been presented 

to the NCNR’s Qingzhen Huang, Jeffrey Lynn, and Taner 

Yildirim. The group is recognized “for their unusually significant 

research contributions concerning the origins of superconductivity 

in the new iron-based superconducting materials. Arguably 

the most important question in all of materials physics today 

concerns the origin of the electron pairing mechanism in 

high-TC superconductors.” The Samuel Wesley Stratton Award, 

first presented in 1962, is granted for outstanding scientific or 

engineering achievements in support of NIST objectives.

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 652 0 1 4 A W A R D S 
Publications: August 1, 2013 to July 31, 2014 

Abakumov, A.M., Tsirlin, A.A., Bakaimi, I., Van Tendeloo, G., 

Lappas, A., “Multiple Twinning as a Structure Directing 

Mechanism in Layered Rock-Salt-Type Oxides: NaMnO2

Polymorphism, Redox Potentials, and Magnetism,” 

Chem. Mater. 26, 3306 (2014).

Ahart, M., DeVreugd, C., Li, J., Viehland, D., Gehring, P.M., 

Hemley, R.J., “X-ray Diffraction Study of the PressureInduced bcc-to-hcp Phase Transition in the Highly 

Magnetostrictive Fe0.81Ga0.19 Alloy,” Phys. Rev. B 88(18), 

184102 (2013).

Akgun, B., Satija, S., Nanda, H., Pirrone, G.F., Shi, X., Engen, 

J.R., Kent, M.S., “Conformational Transition of MembraneAssociated Terminally Acylated HIV-1 Nef,” Structure 21, 

1822 (2013).

Alberca, A., Nemes, N.M., Mompean, F.J., Fehér, T., Simon, F., 

Tornos, J., Leon, C., Munuera, C., Kirby, B.J., Fitzsimmons, 

M.R., Hernando, A., Santamaria, J., Garcia-Hernandez, 

M., “Magnetoelastic Coupling in La0.7Ca0.3MnO3/BaTiO3

Ultrathin Films,” Phys. Rev. B 88(13), 134410 (2013).

Alberca, A., Azpeitia-Urkia, J., Tornos, J., Munuera, C., Mompean, 

F.J., Nemes, N.M., Leon, C., Hernando, A., Fehér, T., Simon, 

F., Kirby, B.J., Fitzsimmons, M.R., Santamaria, J., GarciaHernandez, M., “Magnetoelastic Coupling in Strained 

La0.7Ca0.3MnO3//BaTiO3Thin Films,” Mater. Res. Soc. 

Symp. P. 1587 (2013).

Alsmadi, A.M., Choi, Y., Keavney, D.J., Eid, K.F., Kirby, B.J., Liu, X., 

Leiner, J., Tivakornsasithorn, K., Dobrowolska, M., Furdyna, 

J.K., “Interfacial Exchange Coupling in Fe/(Ga,Mn)As 

Bilayers,” Phys. Rev. B 89(22), 224409 (2014).

Alves, L.M.S., de Lima, B.S., dos Santos, C.A.M., Rabello, A., 

Masunaga, S.H., Neumeier, J.J., Leão, J.B., “Phase Transitions 

in K-Doped MoO2,” J. Appl. Phys. 115(20), 204912 (2014).

Asada, M., Jiang, N., Sendogdular, L., Sokolov, J., Endoh, M.K., 

Koga, T., Fukuto, M., Yang, L., Akgun, B., Dimitriou, M., 

Satija, S., “Melt Crystallization/Dewetting of Ultrathin PEO 

Films via Carbon Dioxide Annealing: the Effects of Polymer 

Adsorbed Layers,” Soft Matter, in press.

Bakaimi, I., Abakumov, A., Green, M.A., Lappas, A., “Crystal, 

Magnetic and Dielectric Studies of the 2D Antiferromagnet: 

β-NaMnO2,” in “Proc. of SPIE,” edited by Teherani, F.H., 

Look, D.C., Rogers, D. J., (Oxide-based Materials and Devices 

V, January 2014, San Francisco, CA) 8987, 898716 (2014).

Baldasseroni, C., Pálsson, G.K., Bordel, C., Valencia, S., Unal, 

A.A., Kronast, F., Nemsak, S., Fadley, C.S., Borchers, J.A., 

Maranville, B.B., Hellman, F., “Effect of Capping Material on 

Interfacial Ferromagnetism in FeRh Thin Films,” J. Appl. Phys. 

115(4), 043919 (2014).

Bañuelos, J.L., Feng, G., Fulvio, P.F., Li, S., Rother, G., Arend, N., 

Faraone, A., Dai, S., Cummings, P.T., Wesolowski, D.J., “The 

Influence of a Hierarchical Porous Carbon Network on the 

Coherent Dynamics of a Nanoconfined Room Temperature 

Ionic Liquid: A Neutron Spin Echo and Atomistic Simulation 

Investigation,” Carbon, in press. [CHRNS]

Barin, G., Krungleviciute, V., Gomez-Gualdron, D.A., Sarjeant, 

A.A., Snurr, R.Q., Hupp, J.T., Yildirim, T., Farha, O.K., 

“Isoreticular Series of (3,24)-Connected Metal-Organic 

Frameworks: Facile Synthesis and High Methane Uptake 

Properties,” Chem. Mater. 26, 1912 (2014).

Barin, G., Krungleviciute, V., Gutov, O., Hupp, J.T., Yildirim, T., 

Farha, O.K., “Defect Creation by Linker Fragmentation in 

Metal-Organic Frameworks and Its Effects on Gas Uptake 

Properties,” Inorg. Chem. 53, 6914 (2014).

Baroudi, K., Yim, C., Wu, H., Huang, Q., Roudebush, J.H., Vavilova, 

E., Grafe, H.-J., Kataev, V., Buechner, B., Ji, H., Kuo, C., Hu, 

Z., Pi, T.-W., Pao, C., Lee, J., Mikhailova, D., Tjeng, L.H., Cava, 

R.J., “Structure and Properties of α-NaFeO2-Type Ternary 

Sodium Iridates,” J. Solid State Chem. 210, 195 (2014).

Basavaraj, M.G., McFarlane, N.L., Lynch, M.L., Wagner, N.J., 

“Nanovesicle Formation and Microstructure in Aqueous 

Ditallowethylesterdimethylammonium Chloride (DEEDMAC) 

Solutions,” J. Colloid Interf. Sci., in press. [CHRNS]

Basden, M., Eldridge, R.B., Farone, J., Feng, E., Hussey, D.S., 

Jacobson, D.L., “Liquid Holdup Profiles in Structured Packing 

Determined via Neutron Radiography,” Ind. Eng. Chem. Res. 

52, 17263 (2013).

66 NIST CENTER FOR NEUTRON RESEARCH PUBLICATIONS
Beers, K.M., Wong, D.T., Jackson, A.J., Wang, X., Pople, J.A., 

Hexemer, A., Balsara, N.P., “Effect of Crystallization on 

Proton Transport in Model Polymer Electrolyte Membranes,” 

Macromolecules 47, 4330 (2014).

Beers, K.M., Yakovlev, S., Jackson, A., Wang, X., Hexemer, A., 

Downing, K.H., Balsara, N.P., “Absence of Schroeder’s 

Paradox in a Nanostructured Block Copolymer Electrolyte 

Membrane,” J. Phys. Chem. B 118, 6785 (2014).

Berk, N.F., “Determination of the Effect Transverse Coherence 

of the Neutron Wave Packet as Employed in Reflectivity 

Investigations of Condensed-Matter Structures. II. Analysis 

of Elastic Scattering using Energy-Gated Wave Packets with 

an Application to Neutron Reflection from Ruled Gratings,” 

Phys. Rev. A 89(3), 033852 (2014).

Bishop, R.L., “Instrumental Approaches to Understanding 

Mesoamerican Economy: Elusive Promises,” Ancient 

Mesoamerica 25(1), 251 (2014).

Blanco, M.A., Perevozchikova, T., Martorana, V., Manno, M., 

Roberts, C.J., “Protein-Protein Interactions in Dilute to 

Concentrated Solutions: α-Chymotrypsinogen in Acidic 

Conditions,” J. Phys. Chem. B 118(22), 5817 (2014).

Bloch, E.D., Hudson, M.R., Mason, J.A., Chavan, S., Crocellà, V., 

Howe, J.D., Lee, K., Dzubak, A.L., Queen, W.L., Zadrozny, 

J.M., Geier, S.J., Lin, L.-C., Gagliardi, L., Smit, B., Neaton, J.B., 

Bordiga, S., Brown, C.M., Long, J.R., “Reversible CO Binding 

Enables Tunable Co/H2 and CO/N2 Separations in MetalOrganic Frameworks with Exposed Divalent Metal Cations,” 

J. Am. Chem. Soc. 136, 10752 (2014).

Brand, P.C., Norbedo, A.J., Sprenger, G.S., “NIST Reactor Solves 

Operational Nuisance Problem using Novel Application of 

Vacuum Transfer Technology,” in “IGORR 15,” (IGORR 15, 

September 2013, Daejeon, Korea) (2013).

Brown, C.M., Ramirez-Cuesta, A.J., Johnson, M.R., García Sakai, 

V., “Chemical Spectroscopy using Neutrons,” Chem. Phys. 

427, 1 (2013).

Brown, C.M., Ramirez-Cuesta, A.J., Her, J.-H., Wheatley, P.S., 

Morris, R.E., “Structure and Spectroscopy of Hydrogen 

Adsorbed in a Nickel Metal-Organic Framework,” 

Chem. Phys. 427, 3 (2013).

Brown, P., Wasbrough, M.J., Gurkan, B.E., Hatton, T.A., 

“CO2-Responsive Microemulsions Based on Reactive 

Ionic Liquids,” Langmuir 30, 4267 (2014). [CHRNS]

Buss, H.L., Brantley, S.L., Scatena, F.N., Bazilievskaya, E.A., Blum, 

A., Schulz, M., Jiménez, R., White, A.F., Rother, G., Cole, 

D., “Probing the Deep Critical Zone Beneath the Luquillo 

Experimental Forest, Puerto Rico,” Earth Surf. Proc. Land. 

38(10), 1170 (2013). [CHRNS]

Cabrera, I., Thompson, J.D., Coldea, R., Prabhakaran, D., Bewley, 

R.I., Guidi, T., Rodriguez-Rivera, J.A., Stock, C., “Excitations 

in the Quantum Paramagnetic Phase of the Quasi-OneDimensional Ising Magnet CoNb2O6 in a Transverse Field: 

Geometric Frustration and Quantum Renormalization 

Effects,” Phys. Rev. B 90(1), 014418 (2014). [CHRNS]

Cai, J., Rao, X., He, Y., Yu, J., Wu, C., Zhou, W., Yildirim, T., 

Chen, B., Qian, G., “A Highly Porous NbO Type MetalOrganic Framework Constructed from an Expanded 

Tetracarboxylate,” Chem. Commun. 50, 1552 (2014).

Cardiel, J.J., Tonggu, L., de la Iglesia, P., Zhao, Y., Pozzo, D.C., 

Wang, L., Shen, A.Q., “Flow-Induced Structured Phase in 

Nonionic Micellar Solutions,” Langmuir 29, 15485 (2013). 

[CHRNS]

Cardiel, J.J., Tonggu, L., Dohnalkova, A.C., de la Iglesia, P., Pozzo, 

D.C., Wang, L., Shen, A.Q., “Worming Their Way into Shape: 

Toroidal Formations in Micellar Solutions,” ACS Nano 7(11), 

9704 (2013). [CHRNS]

Carioni, V.M.O., Nomura, C.S., Yu, L.L., Zeisler, R., “Use 

of Neutron Activation Analysis and LC-ICP-MS in the 

Development of Candidate Reference Materials for 

As Species Determination,” J. Radioanal. Nucl. Chem. 

299, 241 (2014).

Carlson, A.D., Pronyaev, V.G., Capote, R., Hambsch, F.-J., Käppeler, 

F., Lederer, C., Mannhart, W., Mengoni, A., Nelson, R.O., 

Plompen, A.J.M., Schillebeeckx, P., Simakov, S., Talou, 

P., Tagesen, S., Vonach, H., Vorobyev, A., Wallner, A., 

“Improvements and Extensions of the Neutron Cross Section 

and Fluence Standards,” Nucl. Data Sheets 118, 126 (2014).

Carr, S.V., Louca, D., Siewenie, J., Huang, Q., Wang, A., Chen, X., 

Dai, P., “Structure and Composition of the Superconducting 

Phase in Alkali Iron Selenide KyFe1.6+xSe2,” Phys. Rev. B 

89(13), 134509 (2014).

Castellanos, M.M., Pathak, J.A., Leach, W., Bishop, S.M., 

Colby, R.H., “Explaining the Non-Newtonian Character of 

Aggregating Monoclonal Antibody Solutions using SmallAngle Neutron Scattering,” Biophys. J. 107, 469 (2014).

Chapman, K.W., Chupas, P.J., Long, G.G., Bendersky, L.A., Levine, 

L.E., Mompiou, F., Stalick, J.K., Cahn, J.W., “An Ordered 

Metallic Glass Solid Solution Phase that Grows from the 

Melt like a Crystal,” Acta Mater. 62, 58 (2014).

Chatterjee, T., Nakatani, A.I., Van Dyk, A.K., “Shear-Dependent 

Interactions in Hydrophobically Modified Ethylene 

Oxide Urethane (HEUR) Based Rheology ModifierLatex Suspensions: Part 1. Molecular Microstructure,” 

Macromolecules 47, 1155 (2014).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 67PUBLICATIONS
Chen, H., Hsiao, Y.-C., Hu, B., Dadmun, M., “Control of 

Morphology and Function of Low Band Gap Polymer-BisFullerene Mixed Heterojunctions in Organic Photovoltaics 

with Selective Solvent Vapor Annealing,” J. Mater. Chem. 

A 2, 9883 (2014). [CHRNS]

Chen, H., Hsiao, Y.-C., Hu, B., Dadmun, M., “Tuning the 

Morphology and Performance of Low Bandgap Polymer: 

Fullerene Heterojunctions via Solvent Annealing in Selective 

Solvents,” Adv. Funct. Mater., in press. [CHRNS]

Chen, J., Wang, F., Huang, Q., Hu, L., Song, X., Deng, J., Yu, R., 

Xing, X., “Effectively Control Negative Thermal Expansion of 

Single-Phase Ferroelectrics of PbTiO3-(Bi,La)FeO3 over a Giant 

Range,” Sci. Rep. 3, 2458 (2013).

Chen, J., Wu, H., Wu, G., Xiong, Z., Wang, R., Fan, H., Zhou, W., 

Liu, B., Chua, Y., Ju, X., Chen, P., “Lithiated Primary Amine-A 

New Material for Hydrogen Storage,” Chem.-Eur. J. 20, 

6632 (2014).

Chen, W.C., Gentile, T.R., Erwin, R., Watson, S., Ye, Q., Krycka, 

K.L., Maranville, B.B., “3He Spin Filter Based Polarized 

Neutron Capability at the NIST Center for Neutron 

Research,” in “Journal of Physics: Conference Series,” 

edited by Ioffe, A., (International Workshop on Neutron 

Optics and Detectors, June 2013, Munich, Germany) 

528, 012014 (2014). [CHRNS]

Chen, W.C., Gentile, T.R., Ye, Q., Walker, T.G., Babcock, E., 

“On the Limits of Spin-Exchange Optical Pumping of 3He,” 

J. Appl. Phys. 116(1), 014903 (2014).

Cheng, G., Hammouda, B., Perahia, D., “Polystyrene-BlockPolyisoprene Diblock-Copolymer Micelles: Coupled Pressure 

and Temperature Effects,” Macromol. Chem. Phys. 215(8), 

776 (2014). [CHRNS]

Cheng, G., Hammouda, B., Perahia, D., “Effects of Intermicellar 

Interactions on the Dissociation of Block Copolymer Micelles: 

SANS and NMR Studies,” Macromol. Chem. Phys. 215(4), 

341 (2014). [CHRNS]

Chieng, N., Cicerone, M.T., Zhong, Q.N., Liu, M., Pikal, M.J., 

“Characterization of Dynamics in Complex Lyophilized 

Formulations: II. Analysis of Density Variations in Terms of 

Glass Dynamics and Comparisons with Global Mobility, Fast 

Dynamics, and Positron Annihilation Lifetime Spectroscopy 

(PALS),” Eur. J. Pharm. Biopharm. 85, 197 (2013). [CHRNS]

Choi, J., Hore, M.J.A., Clarke, N., Winey, K.I., Composto, R.J., 

“Nanoparticle Brush Architecture Controls Polymer Diffusion 

in Nanocomposites,” Macromolecules 47, 2404 (2014).

Chua, Y.S., Pei, Q., Ju, X., Zhou, W., Udovic, T.J., Wu, G., Xiong, 

Z., Chen, P., Wu, H., “Alkali Metal Hydride Modification on 

Hydrazine Borane for Improved Dehydrogenation,” J. Phys. 

Chem. C 118, 11244 (2014).

Chung, J.-H., Song, Y.-S., Kim, J.-H., Suzuki, T., Katsufuji, T., 

Matsuda, M., Lee, S.-H., “Dynamic Spin Correlations in 

the Frustrated Cubic Phase of MnV2O4,” Phys. Rev. B 

88(9), 094430 (2013).

Clark, N.J., Raththagala, M., Wright, N.T., Buenger, E.A., 

Schildbach, J.F., Krueger, S., Curtis, J.E., “Structures of TraI 

in Solution,” J. Mol. Model. 20, 23208 (2014). [CHRNS]

Clark, N.J., Zhang, H., Krueger, S., Lee, H.J., Ketchem, R.R., 

Kerwin, B., Kanapuram, S.R., Treuheit, M.J., McAuley, A., 

Curtis, J.E., “Small-Angle Neutron Scattering Study of a 

Monoclonal Antibody using Free-Energy Constraints,” J. 

Phys. Chem. B 117, 14029 (2013). [CHRNS]

Coakley, K.J., Vecchia, D.F., Hussey, D.S., Jacobson, D.L., 

“Neutron Tomography of a Fuel Cell: Statistical Learning 

Implementation of a Penalized Likelihood Method,” 

IEEE T. Nucl. Sci. 60(5), 3945 (2013).

Cook, J.C., “Concepts and Engineering Aspects of a Neutron 

Resonance Spin-Echo Spectrometer for the National Institute 

of Standards and Technology Center for Neutron Research,” 

J. Res. Natl. Inst. Stan. 119, 55 (2014).

Couet, A., Motta, A.T., Comstock, R.J., “Hydrogen Pickup 

Measurements in Zirconium Alloys: Relation to Oxidation 

Kinetics,” J. Nucl. Mater., in press.

Crawford, B.E., Anderson, E., Barrón-Palos, L., Bass, C.D., Bass, 

T.D., Fry, J., Gan, K., Haddock, C., Heckel, B.R., Luo, D., 

Malone, R.C., Markoff, D.M., Micherdzinska, A.M., Mumm, 

H.P., Nico, J.S., Opper, A.K., Penn, S., Santra, S., Sarsour, 

M., Sharapov, E.I., Snow, W.M., Swanson, H.E., Van Sciver, 

S., Walbridge, S.B., Yan, H., Zhumabekova, V., “ParityViolating Neutron Spin-Rotation Measurements at NIST,” 

in “International Seminar on Interactions with Nuclei,” 

(International Seminar on Interactions with Nuclei, 

May 2013, Alushta, Ukraine), in press.

Creuziger, A., Hu, L., Gnäupel-Herold, T., Rollett, A.D., 

“Crystallographic Texture Evolution in 1008 Steel Sheet 

during Multi-Axial Tensile Strain Paths,” Integr. Mater. 

Manuf. Innov. 3(1), 1 (2014).

Creuziger, A., Syed, K., Gnäupel-Herold, T., “Measurement 

of Uncertainty in Orientation Distribution Function 

Calculations,” Scripta Mater. 72-73, 55 (2014).

Cui, J., Choi, J.P., Li, G., Polikarpov, E., Darsell, J., Overman, N., 

Olszta, M., Schreiber, D., Bowden, M., Droubay, T., Kramer, 

M.J., Zarkevich, N.A., Wang, L.L., Johnson, D.D., Marinescu, 

M., Takeuchi, I., Huang, Q.Z., Wu, H., Reeve, H., Vuong, N.V., 

Liu, J.P., “Thermal Stability of MnBi Magnetic Materials,” 

J. Phys.-Condens. Mat. 26, 064212 (2014).

68 NIST CENTER FOR NEUTRON RESEARCH PUBLICATIONS
Cui, J., Choi, J.P., Polikarpov, E., Darsell, J., Kramer, M.J., Zarkevich, 

N.A., Wang, L.L., Johnson, D.D., Marinescu, M., Huang, 

Q.Z., Wu, H., Vuong, N.V., Liu, J.P., “Development of MnBi 

Permanent Magnet: Neutron Diffraction of MnBi Powder,” 

J. Appl. Phys. 115(17), 17A743 (2014).

Cunningham, N., Wu, Y., Klingensmith, D., Odette, G.R., 

“On the Remarkable Thermal Stability of Nanostructured 

Ferritic Alloys,” Mater. Sci. Eng. A-Struct., in press.

Cunningham, N.J., Wu, Y., Etienne, A., Haney, E.M., Odette, G.R., 

Stergar, E., Hoelzer, D.T., Kim, Y.D., Wirth, B.D., Maloy, S.A., 

“Effect of Bulk Oxygen on 14YWT Nanostructured Ferritic 

Alloys,” J. Nucl. Mater. 444, 35 (2014).

Cunningham, W.C., “Use of Water Activity Characteristics Enables 

a Simplified Approach for Defining the Reference Moisture 

Condition for FDA Cocoa Powder In-House Reference 

Material,” Anal. Bioanal. Chem. 405(26), 8615 (2013).

Curtis, J.E., Zhang, H., Nanda, H., “SLDMOL: A Tool for the 

Structural Characterization of Thermally Disordered 

Membrane Proteins,” Comput. Phys. Commun., in press.

D’Ortenzio, R.M., Dabkowska, H.A., Dunsiger, S.R., Gaulin, 

B.D., Gingras, M.J.P., Goko, T., Kycia, J.B., Liu, L., Medina, 

T., Munsie, T.J., Pomaranski, D., Ross, K.A., Uemura, Y.J., 

Williams, T.J., Luke, G.M., “Unconventional Magnetic 

Ground State in Yb2Ti2O7,” Phys. Rev. B 88(13), 134428 

(2013).

Danial, M., Tran, C.M.-N., Jolliffe, K.A., Perrier, S., “Thermal 

Gating in Lipid Membranes using Thermoresponsive 

Cyclic Peptide-Polymer Conjugates,” J. Am. Chem. Soc. 

136(22), 8018 (2014). [CHRNS]

DeCaluwe, S.C., Kienzle, P.A., Bhargava, P., Baker, A.M., Dura, 

J.A., “Phase Segregation of Sulfonate Groups in Nafion 

Interface Lamellae, Quantified via Neutron Reflectometry 

Fitting Techniques for Multi-Layered Structures,” 

Soft Matter, in press.

de la Iglesia, P., Pozzo, D.C., “Effects of Superstaturation on 

the Structure and Properties of Poly(9,9-Dioctyl Fluorene) 

Organogels,” Soft Matter 9, 11214 (2013). [CHRNS]

Dhital, C., Hogan, T., Zhou, W., Chen, X., Ren, Z., Pokharel, M., 

Okada, Y., Heine, M., Tian, W., Yamani, Z., Opeil, C., Helton, 

J.S., Lynn, J.W., Wang, Z., Madhavan, V., Wilson, S.D., 

“Carrier Localization and Electronic Phase Separation in a 

Doped Spin-Orbit-Driven Mott Phase in Sr3(Ir1-xRux)2O7,” 

Nat. Commun. 5(3377), 1 (2014).

Dimeo, R.M., “The NIST Center for Neutron Research,” 

HANARO Report 71, 18 (2013).

Dimeo, R.M., “Wave Packet Scattering from Time-Varying 

Potential Barriers in One Dimension,” Am. J. Phys. 

82(2), 142 (2014).

Ding, C., Gong, X., Man, H., Zhi, G., Guo, S., Zhao, Y., Wang, H., 

Chen, B., Ning, F.L., “The Suppression of Curie Temperature 

by Sr Doping in Diluted Ferromagnetic Semiconductor 

(La1-xSrx)(Zn1-yMny)AsO,” Europhys. Lett. 107, 17004 (2014).

Disseler, S.M., “Direct Evidence for the All-In/All-Out Magnetic 

Structure in the Pyrochlore Iridates from Muon Spin 

Relaxation,” Phys. Rev. B 89(14), 140413 (2014).

Downing, R.G., “NIST Neutron Depth Profiling Facility: 2013, 

Invited,” T. Am. Nucl. Soc. 109, 527 (2013).

Downing, R.G., “Enhanced Reaction Rates in NDP Analysis with 

Neutron Scattering,” Rev. Sci. Instrum. 85(4), 045109 (2014).

Du, W., Yuan, G., Wang, M., Han, C.C., Satija, S.K., Akgun, B., 

“Initial Stages of Interdiffusion between Asymmetrical 

Polymeric Layers: Glassy Polycarbonate and Melt Poly(Methyl 

Methacrylate) Interface Studied by Neutron Reflectometry,” 

Macromolecules 47, 713 (2014).

Eberle, A.P.R., Martys, N.N., Porcar, L., Kline, S.R., George, W.L., 

Kim, J.M., Butler, P.D., Wagner, N.J., “Shear Viscosity and 

Structural Scalings in Model Adhesive Hard-Sphere Gels,” 

Phys. Rev. E 89(5), 050302 (2014). [CHRNS]

Edmonds, M.T., Hellerstedt, J.T., Tadich, A., Schenk, A., O’Donnell, 

K.M., Tosado, J., Butch, N.P., Syers, P., Paglione, J., Fuhrer, 

M.S., “Air-Stable Electron Depletion of Bi2Se3 using 

Molybdenum Trioxide into the Topological Regime,” 

ACS Nano 8(6), 6400 (2014).

Ehlers, G., Podlesnyak, A.A., Frontzek, M., Freitas, R.S., Ghivelder, 

L., Gardner, J.S., Shiryaev, S.V., Barilo, S., “A Detailed Study 

of the Magnetic Phase Transition in CuCrO2,” J. Phys.: 

Condens. Matter 25, 496009 (2013). [CHRNS]

Eriksson, S.M., Mackey, E.A., Lindstrom, R.M., Lamaze, G.P., 

Grogan, K.P., Brady, D.E., “Delayed-Neutron Activation 

Analysis at NIST,” J. Radioanal. Nucl. Chem. 298, 1819 

(2013).

Erlkamp, M., Grobelny, S., Faraone, A., Czeslik, C., Winter, R., 

“Solvent Effects on the Dynamics of Amyloidogenic Insulin 

Revealed by Neutron Spin Echo Spectroscopy,” J. 

Phys. Chem. B 118, 3310 (2014). [CHRNS]

Fairweather, J.D., Spernjak, D., Spendelow, J., Mukundan, 

R., Hussey, D., Jacobson, D., Borup, R.L., “Evaluation of 

Transient Water Content during PEMFC Operational Cycles 

by Stroboscopic Neutron Imaging,” ECS Transactions 

58(1), 301 (2013).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 69PUBLICATIONS
Fajalia, A.I., Tsianou, M., “Charging and Un-Charging a Neutral 

Polymer in Solution: A Small-Angle Neutron Scattering 

Investigation,” J. Phys. Chem. B, in press. [CHRNS]

Faraone, A., Fratini, E., Garai, S., Müller, A., Tyagi, M., Jenkins, 

T., Mamontov, E., Paul, R.L., Copley, J.R.D., Baglioni, P., 

“Incoherent Quasielastic Neutron Scattering Study of the 

Relaxation Dynamics in Molybdenum-Oxide Keplerate-Type 

Nanocages,” J. Phys. Chem. C 118, 13300 (2014). [CHRNS]

Ferguson, P.P., Le, D.-B., Todd, A.D.W., Martine, M.L., Trussler, S., 

Obrovac, M.N., Dahn, J.R., “Nanostructured Sn30Co30C40

Alloys for Lithium-Ion Battery Negative Electrodes Prepared 

by Horizontal Roller Milling,” J. Alloy Compd. 595, 138 

(2014).

Ferguson, P.P., Todd, A.D.W., Martine, M.L., Dahn, J.R., “Structure 

and Performance of Tin-Cobalt-Carbon Alloys Prepared by 

Attriting, Roller Milling and Sputtering,” J. Electrochem. 

Soc. 161(3), A342 (2014).

Ferrier, Jr., R.C., Lee, H.-S., Hore, M.J.A., Caporizzo, M., 

Eckmann, D.M., Composto, R.J., “Gold Nanorod Linking 

to Control Plasmonic Properties in Solution and Polymer 

Nanocomposites,” Langmuir 30, 1906 (2014).

Fobes, D., Zaliznyak, I.A., Xu, Z., Zhong, R., Gu, G., Tranquada, 

J.M., Harriger, L., Singh, D., Ovidiu Garlea, V., Lumsden, M., 

Winn, B., “Ferro-Orbital Ordering Transition in Iron Telluride 

Fe1+yTe,” Phys. Rev. Lett. 112(18), 187202 (2014).

Fritsch, K., Kermarrec, E., Ross, K.A., Qiu, Y., Copley, J.R.D., 

Pomaranski, D., Kycia, J.B., Dabkowska, H.A., Gaulin, B.D., 

“Temperature and Magnetic Field Dependence of Spin-Ice 

Correlations in the Pyrochlore Magnet Tb2Ti2O7,” 

Phys. Rev. B 90(1), 014429 (2014). [CHRNS]

Furukawa, H., Gándara, F., Zhang, Y.-B., Jiang, J., Queen, W.L., 

Hudson, M.R., Yaghi, O.M., “Water Adsorption in Porous 

Metal-Organic Frameworks and Related Materials,” 

J. Am. Chem. Soc. 136, 4369 (2014).

Gadipelli, S., Travis, W., Zhou, W., Guo, Z., “A Thermally Derived 

and Optimized Structure from ZIF-8 with Giant Enhancement 

in CO2 Uptake,” Energ. Environ. Sci. 7, 2232 (2014).

Gamz ̇a, M.B., Tomczak, J.M., Brown, C., Puri, A., Kotliar, G., 

Aronson, M.C., “Electronic Correlations in FeGa3 and 

the Effect of Hole Doping on its Magnetic Properties,” 

Phys. Rev. B 89(19), 195102 (2014).

Ganapatibhotla, L.V.N.R., Maranas, J.K., “Interplay of Surface 

Chemistry and Ion Content in Nanoparticle-Filled Solid 

Polymer Electrolytes,” Macromolecules 47, 3625 (2014). 

[CHRNS]

Gao, J., Chen, W., Dou, L., Chen, C.-C., Chang, W.-H., Liu, Y., Li, 

G., Yang, Y., “Elucidating Double Aggregation Mechanisms 

in the Morphology Optimization of DiketopyrrolopyrroleBased Narrow Bandgap Polymer Solar Cells,” Adv. Mater. 

26, 3142 (2014).

Gao, W.-Y., Cai, R., Meng, L., Wojtas, L., Zhou, W., Yildirim, T., 

Shi, X., Ma, S., “Quest for a Highly Connected Robust Porous 

Metal-Organic Framework on the Basis of a Bifunctional 

Linear Linker and a Rare Heptanuclear Zinc Cluster,” 

Chem. Commun. 49, 10516 (2013).

Gao, Y., Nieuwendaal, R., Hammouda, B., Berciu, C., Nicastro, 

D., Douglas, J., Xu, B., Horkay, F., “Supramolecular SelfAssembly Inside Living Mammalian Cells,” Mater. Res. 

Soc. Symp. P., 1622, 85 (2014). [CHRNS]

Ge, W., Devreugd, C.P., Phelan, D., Zhang, Q., Ahart, M., Li, 

J., Luo, H., Boatner, L.A., Viehland, D., Gehring, P.M., 

“Lead-Free and Lead-Based ABO3 Perovskite Relaxors with 

Mixed-Valence A-Site and B-Site Disorder: Comparative 

Neutron Scattering Structural Study of (Na1/2Bi1/2)TiO3 and 

Pb(Mg1/3Nb2/3)O3,” Phys. Rev. B 88(17), 174115 (2013).

Gentile, L., Behrens, M.A., Porcar, L., Butler, P., Wagner, N.J., 

Olsson, U., “Multilamellar Vesicle Formation from a Planar 

Lamellar Phase under Shear Flow,” Langmuir 30, 8316 

(2014). [CHRNS]

Gentile, T.R., Chen, W.C., “Polarized 3He Spin Filters for Neutron 

Science,” in “Proceedings of Science,” (XVth International 

Workshop on Polarized Sources, and Polarimetry, August 

2013, Charlottesville, VA), 1 (2014).

Gericke, A., Leslie, N.R., Lösche, M., Ross, A.H., “PI(4,5)

P2-Mediated Cell Signaling: Emerging Principles and PTEN 

as a Paradigm for Regulatory Mechanism,” in “Advances in 

Experimental Medicine and Biology,” (Springer, Netherlands, 

Netherlands, Netherlands) 85 (2013).

Gilliam, D.M., Yue, A.T., “Improvements in the Characterization of 

Actinide Targets by Low Solid-Angle Counting,” J. Radioanal. 

Nucl. Chem. 299, 1061 (2014).

Glassman, M.J., Olsen, B.D., “Structure and Mechanical Response 

of Protein Hydrogels Reinforced by Block Copolymer 

Self-Assembly,” Soft Matter 9, 6814 (2013).

Gnäupel-Herold, T., Iadicola, M.A., Creuziger, A.A., Foecke, T., 

Hu, L., “Interpretation of Diffraction Data from In-Situ Stress 

Measurements during Biaxial Sheet Metal Forming,” Mater. 

Sci. Forum 768-769, 441 (2013).

Gnäupel-Herold, T., Green, D.E., Foecke, T., Iadicola, M.A., 

“Through-Thickness Stresses in Automotive Sheet Metal 

after Plane Strain Channel Draw,” Mater. Sci. Forum 

768-769, 433 (2013).

70 NIST CENTER FOR NEUTRON RESEARCH PUBLICATIONS
Gnäupel-Herold, T., Slotwinski, J., Moylan, S., “Neutron 

Measurements of Stresses in a Test Artifact Produced by 

Laser-Based Additive Manufacturing,” AIP Conf. Proc. 

1581, 1205 (2014).

Godfrin, P.D., Castañeda-Priego, R., Liu, Y., Wagner, N.J., 

“Intermediate Range Order and Structure in Colloidal 

Dispersions with Competing Interactions,” J. Chem. Phys. 

139(15), 154904 (2013).

Godfrin, P.D., Valadez-Pérez, N.E., Castañeda-Priego, R., 

Wagner, N.J., Liu, Y., “Generalized Phase Behavior 

of Cluster Formation in Colloidal Dispersions with 

Competing Interactions,” Soft Matter 10, 5061 (2014).

Greene, P.K., Kirby, B.J., Lau, J.W., Borchers, J.A., Fitzsimmons, 

M.R., Liu, K., “Deposition Order Dependent Magnetization 

Reversal in Pressure Graded Co/Pd Films,” Appl. Phys. Lett. 

104(15), 152401 (2014).

Gressier, V., Bonaldi, A.C., Dewey, M.S., Gilliam, D.M., Harano, 

H., Masuda, A., Matsumoto, T., Moiseev, N., Nico, J.S., 

Nolte, R., Oberstedt, S., Roberts, N.J., Röttger, S., Thomas, 

D.J., “International Key Comparison of Neutron Fluence 

Measurements in Monoenergetic Neutron Fields - 

CCRI(III)-K11,” Metrologia, in press.

Grogan, K.P., O’Kelly, D.J., “Analytical Applications of Delayed 

and Instrumental Neutron Activation Analysis,” J. Radioanal. 

Nucl. Chem. 299, 543 (2014).

Grutter, A.J., Yang, H., Kirby, B.J., Fitzsimmons, M.R., Aguiar, 

J.A., Browning, N.D., Jenkins, C.A., Arenholz, E., Mehta, 

V.V., Alaan, U.S., Suzuki, Y., “Interfacial Ferromagnetism 

in LaNiO3/CaMnO3 Superlattices,” Phys. Rev. Lett. 111(8), 

087202 (2013).

Gurnon, A.K., Godfrin, P.D., Wagner, N.J., Eberle, A.P.R., Butler, P., 

Porcar, L., “Measuring Material Microstructure under Flow 

using 1-2 Plane Flow-Small Angle Neutron Scattering,” 

J. Vis. Exp. (84), e51068 (2014).

Gurnon, A.K., López-Barrón, C., Eberle, A.P.R., Porcar, L., Wagner, 

N.J., “Spatiotemporal Stress and Structure Evolution in 

Dynamically Sheared Polymer-Like Micellar Solutions,” 

Soft Matter 10, 2889 (2014).

Gurnon, A.K., López-Barrón, C., Wasbrough, M.J., Porcar, 

L., Wagner, N.J., “Spatially Resolved Concentration and 

Segmental Flow Alignment in a Shear-Banding Solution 

of Polymer-Like Micelles,” ACS Macro Lett. 3, 276 (2014). 

[CHRNS]

Gutov, O.V., Bury, W., Gomez-Gualdron, D.A., Krungleviciute, V., 

Fairen-Jimenez, D., Mondloch, J.E., Sarjeant, A.A., Al-Juaid, 

S.S., Snurr, R.Q., Hupp, J.T., Yildirim, T., Farha, O.K., “WaterStable Zirconium-Based Metal-Organic Framework Material 

with High-Surface Area and Gas-Storage Capacities,” 

Chem.-Eur. J., in press.

Hammouda, B., “Are Bragg Peaks Gaussian?,” J. Res. Natl. Inst. 

Stan. 119, 15 (2014). [CHRNS]

Hammouda, B., Mildner, D.F.R., Brûlet, A., Desert, S., “Insight into 

Neutron Focusing: the Out-of-Focus Condition,” J. Appl. 

Crystallogr. 46, 1361 (2013). [CHRNS]

Harris, A.B., Yildirim, T., “Spin Dynamics of Trimers on a Distorted 

Kagome Lattice,” Phys. Rev. B 88(1), 014411, (2013).

He, Y., Zhou, W., Yildirim, T., Chen, B., “A Series of Metal-Organic 

Frameworks with High Methane Uptake and an Empirical 

Equation for Predicting Methane Storage Capacity,” Energ. 

Environ. Sci. 6(9), 2735 (2013).

He, Y., Guo, Z., Xiang, S., Zhang, Z., Zhou, W., Fronczek, F.R., 

Parkin, S., Hyde, S.T., O’Keeffe, M., Chen, B., “Metastable 

Interwoven Mesoporous Metal-Organic Frameworks,” 

Inorg. Chem. 52, 11580 (2013).

He, Y., Zhou, W., Qian, G., Chen, B., “Methane Storage in 

Metal-Organic Frameworks,” Chem. Soc. Rev., in press.

Heinrich, F., Nanda, H., Go, H.Z., Bachert, C., Lösche, M., 

Linstedt, A.D., “Myristoylation Restricts Orientation of the 

GRASP Domain on Membranes and Promotes Membrane 

Tethering,” J. Biol. Chem. 289(14), 9683 (2014).

Heinrich, F., Lösche, M., “Zooming in on Disordered Systems: 

Neutron Reflection Studies of Proteins Associated with 

Fluid Membranes,” BBA-Biomembranes, in press.

Helgeson, M.E., Gao, Y., Moran, S.E., Lee, J., Godfrin, M., Tripathi, 

A., Bose, A., Doyle, P.S., “Homogeneous Percolation 

Versus Arrested Phase Separation in Attractively-Driven 

Nanoemulsion Colloidal Gels,” Soft Matter 10, 3122 

(2014). [CHRNS]

Heller, W.T., Urban, V.S., Lynn, G.W., Weiss, K.L., O’Neill, H.M., 

Pingali, S.V., Qian, S., Littrell, K.C., Melnichenko, Y.B., 

Buchanan, M.V., Selby, D.L., Wignall, G.D., Butler, P.D., 

Myles, D.A., “The Bio-SANS Instrument at the High Flux 

Isotope Reactor of Oak Ridge National Laboratory,” 

J. Appl. Crystallogr., in press.

Hellsing, M.S., Kwaambwa, H.M., Nermark, F.M., Nkoane, 

B.B.M., Jackson, A.J., Wasbrough, M.J., Berts, I., Porcar, L., 

Rennie, A.R., “Structure of Flocs of Latex Particles Formed 

by Addition of Protein from Moringa Seeds,” Colloid 

Surface. A, in press. [CHRNS]

Heuser, B.J., Trinkle, D.R., Jalarvo, N., Serio, J., Schiavone, E.J., 

Mamontov, E., Tyagi, M., “Direct Measurement of Hydrogen 

Dislocation Pipe Diffusion in Deformed Polycrystalline Pd 

Using Quasielastic Neutron Scattering,” Phys. Rev. Lett. 

113(2), 025504 (2014). [CHRNS]

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 71PUBLICATIONS
Hoarfrost, M.L., He, Y., Lodge, T.P., “Lower Critical Solution 

Temperature Phase Behavior of Poly(n-Butyl Methacrylate) 

in Ionic Liquid Mixtures,” Macromolecules 46, 9464 (2013).

Hong, T., Schmidt, K.P., Coester, K., Awwadi, F.F., Turnbull, M.M., 

Qiu, Y., Rodriguez-Rivera, J.A., Zhu, M., Ke, X., Aoyama, 

C.P., Takano, Y., Cao, H., Tian, W., Ma, J., Custelcean, R., 

Zhou, H.D., Matsuda, M., “Magnetic Ordering Induced by 

Interladder Coupling in the Spin-1/2 Heisenberg Two-Leg 

Ladder Antiferromagnet C9H18N2CuBr4,” Phys. Rev. B 

89(17), 174432 (2014). [CHRNS]

Hore, M.J.A., Ford, J., Ohno, K., Composto, R.J., Hammouda, 

B., “Direct Measurements of Polymer Brush Conformation 

using Small-Angle Neutron Scattering (SANS) from Highly 

Grafted Iron Oxide Nanoparticles in Homopolymer Melts,” 

Macromolecules 46, 9341 (2013). [CHRNS]

Hore, M.J.A., Composto, R.J., “Functional Polymer Nanocomposites

Enhanced by Nanorods,” Macromolecules 47, 875 (2014). 

[CHRNS]

Hore, M.J.A., Hammouda, B., Li, Y., Cheng, H., “Co-Nonsolvency 

of Poly(n-isopropylacrylamide) in Deuterated Water/Ethanol 

Mixtures,” Macromolecules 46, 7894 (2013). [CHRNS]

Horkay, F., “Ion Polymer Interactions in DNA Solutions and Gels,” 

Macromol. Symp. 329, 19 (2013). [CHRNS]

Horkay, F., Basser, P.J., Hecht, A.-M., Geissler, E., “Structure and 

Interactions in Hyaluronic Acid Solutions,” Polym. Mater. 

Sci. Eng. 108, 111 (2013). [CHRNS]

Hulvey, Z., Lawler, K.V., Qiao, Z., Zhou, J., Fairen-Jimenez, D., 

Snurr, R.Q., Ushakov, S.V., Navrotsky, A., Brown, C. M., 

Forster, P.M., “Noble Gas Adsorption in Copper Trimesate, 

HKUST-1: An Experimental and Computational Study,” 

J. Phys. Chem. C 117, 20116 (2013).

Hussey, D.S., Coakley, K.J., Baltic, E., Jacobson, D.L., “Improving 

Quantitative Neutron Radiography through Image 

Restoration,” Nucl. Instrum. Meth. A 729, 316 (2013).

Hussey, D.S., Spernjak, D., Wu, G., Jacobson, D.L., Liu, D., 

Khaykovich, B., Gubarev, M.V., Fairweather, J., Mukundan, 

R., Lujan, R., Zelenay, P., Borup, R.L., “Neutron Imaging of 

Water Transport in Polymer-Electrolyte Membranes and 

Membrane-Electrode Assemblies,” ECS Transactions 

58(1), 293 (2013).

Inceoglu, S., Young, N.P., Jackson, A.J., Kline, S.R., Costeux, S., 

Balsara, N.P., “Effect of Supercritical Carbon Dioxide on the 

Thermodynamics of Model Blends of Styrene-Acrylonitrile 

Copolymer and Poly(Methyl Methacrylate) Studied by 

Small-Angle Neutron Scattering,” Macromolecules 

46, 6345 (2013). [CHRNS]

Jain, N., Liu, C.K., Hawkett, B.S., Warr, G.G., Hamilton, W.A., 

“Application of Small-Angle Neutron Scattering to the Study 

of Forces between Magnetically Chained Monodisperse 

Ferrofluid Emulsion Droplets,” J. Appl. Crystallogr. 

47, 41 (2014). [CHRNS]

Jalarvo, N., Gourdon, O., Ehlers, G., Tyagi, M., Kumar, S.K., 

Dobbs, K.D., Smalley, R.J., Guise, W.E., Ramirez-Cuesta, A., 

Wildgruber, C., Crawford, M.K., “Structure and Dynamics 

of Octamethyl-POSS Nanoparticles,” J. Phys. Chem. C 

118, 5579 (2014). [CHRNS]

Jeong, Y., Gnäupel-Herold, T., Barlat, F., Iadicola, M., Creuziger, 

A., Lee, M.-G., “Evaluation of Biaxial Flow Stress Based 

on Elasto-Viscoplastic Self-Consistent Analysis of X-ray 

Diffraction Measurements,” Int. J. Plasticity, in press.

Jiao, Y., Parra, J., Akcora, P., “Effect of Ionic Groups on 

Polymer-Grafted Magnetic Nanoparticle Assemblies,” 

Macromolecules 47, 2030 (2014). [CHRNS]

Jin, L., Mathur, R., Rother, G., Cole, D., Bazilevskaya, E., Williams, 

J., Carone, A., Brantley, S., “Evolution of Porosity and 

Geochemistry in Marcellus Formation Black Shale during 

Weathering,” Chem. Geol. 356, 50 (2013). [CHRNS]

Jones, R., “Specimen Name: NIST nSoft Consortium,” Adv. 

Mater. Processes 172, 48 (2014).

Kamazawa, K., Harada, M., Araki, T., Matsuo, Y., Tyagi, M., 

Sugiyama, J., “Interrelationship between Number of Mobile 

Protons, Diffusion Coefficient, and AC Conductivity in 

Superprotonic Conductors, CsHSO4 and Rb3H(SeO4)2,” 

J. Phys. Soc. Jpn. 83, 074604 (2014). [CHRNS]

Kandlakunta, P., Cao, L.R., “Neutron Conversion Efficiency and 

Gamma Interference with Gadolinium,” J. Radioanal. Nucl. 

Chem. 300, 953 (2014).

Karabiyik, U., Mao, M., Satija, S.K., Esker, A.R., “Determination 

of Thicknesses and Refractive Indices of Polymer Thin Films 

by Multiple Incident Media Ellipsometry,” Thin Solid Films, 

in press.

Ke, X., Birol, T., Misra, R., Lee, J.-H., Kirby, B.J., Schlom, D.G., 

Fennie, C.J., Freeland, J.W., “Structural Control of Magnetic 

Anisotropy in a Strain-Driven Multiferroic EuTiO3 Thin Film,” 

Phys. Rev. B 88(9), 094434 (2013).

Kelley, E.G., Murphy, R.P., Seppala, J.E., Smart, T.P., Hann, 

S.D., Sullivan, M.O., Epps, T.H., “Size Evolution of Highly 

Amphiphilic Macromolecular Solution Assemblies via a 

Distinct Bimodal Pathway,” Nat. Commun. 5, 3599 (2014).

72 NIST CENTER FOR NEUTRON RESEARCH PUBLICATIONS
Kennedy, R.D., Krungleviciute, V., Clingerman, D.J., Mondloch, 

J.E., Peng, Y., Wilmer, C.E., Sarjeant, A.A., Snurr, R.Q., Hupp, 

J.T., Yildirim, T., Farha, O.K., Mirkin, C.A., “Carborane-Based 

Metal-Organic Framework with High Methane and Hydrogen 

Storage Capacities,” Chem. Mater. 25, 3539 (2013).

Khodadadi, S., Clark, N.J., McAuley, A., Cristiglio, V., Curtis, J.E., 

Shalaev, E.Y., Krueger, S., “Influence of Sorbitol on Protein 

Crowding in Solution and Freeze-Concentrated Phases,” 

Soft Matter 10, 4056 (2014). [CHRNS]

Kim, D., Syers, P., Butch, N.P., Paglione, J., Fuhrer, M.S., 

“Ambipolar Surface State Thermoelectric Power of 

Topological Insulator Bi2Se3,” Nano Lett. 14, 1701 (2014).

Kim, J., Gao, Y., Hebebrand, C., Peirtsegaele, E., Helgeson, M.E., 

“Polymer-Surfactant Complexation as a Generic Route to 

Responsive Viscoelastic Nanoemulsions,” Soft Matter 9, 

6897 (2013).

Kim, M.D., Dergunov, S.A., Richter, A.G., Durbin, J., Shmakov, 

S.N., Jia, Y., Kenbeilova, S., Orazbekuly, Y., Kengpeiil, 

A., Lindner, E., Pingali, S.V., Urban, V.S., Weigand, S., 

Pinkhassik, E., “Facile Directed Assembly of Hollow Polymer 

Nanocapsules within Spontaneously Formed Catanionic 

Surfactant Vesicles,” Langmuir 30, 7061 (2014).

Kim, S.Y., Zukoski, C.F., “Molecular Weight Effects on Particle and 

Polymer Microstructure in Concentrated Polymer Solutions,” 

Macromolecules 46, 6634 (2013).

Kizilay, E., Dinsmore, A.D., Hoagland, D.A., Sun, L., Dubin, P.L., 

“Evolution of Hierarchical Structures in PolyelectrolyteMicelle Coacervates,” Soft Matter 9(30), 7320 (2013). 

[CHRNS]

Kline, S.R., “2013 NCNR Annual Report,” NIST SP 1168, (2014).

Kofu, M., Kajiwara, T., Gardner, J.S., Simeoni, G.G., Tyagi, M., 

Faraone, A., Nakajima, K., Ohira-Kawamura, S., Nakano, 

M., Yamamuro, O., “Magnetic Relaxations in a Tb-Based 

Single Molecule Magnet Studied by Quasielastic Neutron 

Scattering,” Chem. Phys. 427, 147 (2013). [CHRNS]

Kong, G.-Q., Han, Z.-D., He, Y., Ou, S., Zhou, W., Yildirim, T., 

Krishna, R., Zou, C., Chen, B., Wu, C.-D., “Expanded Organic 

Building Units for the Construction of Highly Porous MetalOrganic Frameworks,” Chem.-Eur. J. 19, 14886 (2013).

Kotaka, T., Tabuchi, Y., Pasaogullari, U., Wang, C.-Y., “The 

Influence of Liquid Water Interaction between Channel, 

GDL and CL on Cell Performance,” ECS Transactions 58(1), 

1033 (2013).

Krayer, L., Lau, J.W., Kirby, B.J., “Structural and Magnetic Etch 

Damage in CoFeB,” J. Appl. Phys. 115(17), 17B751 (2014).

Krueger, S., Shin, J.-H., Curtis, J.E., Rubinson, K.A., Kelman, Z., 

“The Solution Structure of Full-length Dodecameric MCM by 

SANS and Molecular Modeling,” Proteins, in press. [CHRNS]

Kruk, I.I., Zajdel, P., “Single Crystal Growth and Structural 

Characterization of Iron Telluride Doped with Chromium 

and Zinc,” J. Cryst. Growth, in press.

Kumari, H., Kline, S.R., Fowler, D.A., Mossine, A.V., Deakyne, 

C.A., Atwood, J.L., “Solution Superstructures: Truncated 

Cubeoctahedron Structures of Pyrogallol[4]arene 

Nanoassemblies,” Chem. Commun. 50, 109 (2014).

Kumari, H., Kline, S.R., Atwood, J.L., “Aqueous Solubilization of 

Hydrophobic Supramolecular Metal-Organic Nanocapsules,” 

Chem. Sci. 5, 2554 (2014). [CHRNS]

LaManna, J.M., Chakraborty, S., Gagliardo, J.J., Mench, M.M., 

“Isolation of Transport Mechanisms in PEFCs using High 

Resolution Neutron Imaging,” Int. J. Hydrogen Energ. 39, 

3387 (2014).

Lavelle, C.M., Deacon, R.M., Hussey, D.S., Coplan, M., Clark, C.W., 

“Characterization of Boron Coated Vitreous Carbon Foam 

for Neutron Detection,” Nucl. Instrum. Meth. A 729, 

346 (2013).

Lee, C.L., Dowding, P.J., Doyle, A.R., Bakker, K.M., Lam, S.S., 

Rogers, S.E., Routh, A.F., “The Structures of Salicylate 

Surfactants with Long Alkyl Chains in Non-Aqueous Media,” 

Langmuir 29, 14763 (2013). [CHRNS]

Lee, J.S., Richardella, A., Rench, D.W., Fraleigh, R.D., Flanagan, 

T.C., Borchers, J.A., Tao, J., Samarth, N., “Ferromagnetism 

and Spin-Dependent Transport in n-type Mn-Doped Bismuth 

Telluride Thin Films,” Phys. Rev. B 89(17), 174425 (2014).

Lee, K., Isley, III.,W.C., Dzubak, A.L., Verma, P., Stoneburner, S.J., 

Lin, L.-C., Howe, J.D, Bloch, E.D., Reed, D.A., Hudson, M.R., 

Brown, C.M., Long, J.R., Neaton, J.B., Smit, B., Cramer, 

C.J., Truhlar, D.G., Gagliardi, L., “Design of a Metal-Organic 

Framework with Enhanced Back Bonding for the Separation 

of N2 and CH4,” J. Am. Chem. Soc. 136, 698 (2014).

Lehnert, R., Snow, W.M., Yan, H., “A First Experimental Limit on 

In-Matter Torsion from Neutron Spin Rotation in Liquid 4He,” 

Phys. Lett. B 730, 353 (2014).

Leiner, J., Kirby, B.J., Fitzsimmons, M.R., Tivakornsasithorn, K., 

Liu, X., Furdyna, J.K., Dobrowolska, M., “Magnetic Depth 

Profile in GaMnAs Layers with Vertically Graded Mn 

Concentrations,” J. Magn. Magn. Mater. 350, 135 (2014).

Leiner, J., Thampy, V., Christianson, A.D., Abernathy, D.L., Stone, 

M.B., Lumsden, M.D., Sefat, A.S., Sales, B.C., Hu, J., Mao, 

Z., Bao, W., Broholm, C., “Modified Magnetism within the 

Coherence Volume of Superconducting Fe1+δ SexTe1-x,” 

Phys. Rev. B, in press. [CHRNS]

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 73PUBLICATIONS
Leys, J., Subramanian, D., Rodezno, E., Hammouda, B., 

Anisimov, M.A., “Mesoscale Phenomena in Solutions of 

3-Methylpyridine, Heavy Water, and an Antagonistic Salt,” 

Soft Matter 9, 9326 (2013). [CHRNS]

Li, B., Wen, H.-M., Wang, H., Wu, H., Tyagi, M., Yildirim, T., Zhou, 

W., Chen, B., “A Porous Metal-Organic Framework with 

Dynamic Pyrimidine Groups Exhibiting Record High Methane 

Storage Working Capacity,” J. Am. Chem. Soc. 136, 6207 

(2014). [CHRNS]

Li, F., Parnell, S.R., Hamilton, W.A., Maranville, B.B., Wang, 

T., Semerad, R., Baxter, D.V., Cremer, J.T., Pynn, R., 

“Superconducting Magnetic Wollaston Prism for Neutron 

Spin Encoding,” Rev. Sci. Instrum. 85(5), 053303 (2014).

Li, G.-N., Rao, G.-H., Huang, Q.-Z., Gao, Q.-Q., Luo, J., Liu, 

G.-Y., Li, J.-B., Liang, J.-K., “Phase Separation in Sr Doped 

BiMnO3,” Chinese Phys. B 23(3), 036401 (2014).

Li, X., ShamsiJazeyi, H., Pesek, S.L., Agrawal, A., Hammouda, B., 

Verduzco, R., “Thermoresponsive PNIPAAM Bottlebrush 

Polymers with Tailored Side-Chain Length and End-Group 

Structure,” Soft Matter 10, 2008 (2014). [CHRNS]

Li, X., Porcar, L., Sánchez-Diáz, L.E., Do, C., Liu, Y., Kim, T.-H., 

Smith, G.S., Hamilton, W.A., Hong, K., Chen, W.-R., 

“Influence of Molecular Solvation on the Conformation 

of Star Polymers,” ACS Macro Lett. 3(5), 458 (2014). 

Li, X., Ma, X., Su, D., Liu, L., Chisnell, R., Ong, S.P., Chen, H., 

Toumar, A., Idrobo, J.-C., Lei, Y., Bai, J., Wang, F., Lynn, J.W., 

Lee, Y.S., Ceder, G., “Direct Visualization of the Jahn-Teller 

Effect Coupled to Na Ordering in Na5/8MnO2,” Nat. Mater. 

13, 586 (2014).

Lin, K., Wu, H., Wang, F., Rong, Y., Chen, J., Deng, J., Yu, R., Fang, 

L., Huang, Q., Xing, X., “Structure and Thermal Expansion 

of the Tungsten Bronze Pb2KNb5O15,” Dalton T. 43, 

7037 (2014).

Lin, K., Rong, Y., Wu, H., Huang, Q., You, L., Ren, Y., Fan, L., Chen, 

J., Xing, X., “Ordered Structure and Thermal Expansion in 

Tungsten Bronze Pb2K0.5Li0.5Nb5O15,” Inorg. Chem., in press.

Lindstrom, R.M., “The Half-Lives of 90mY and 97Ru,” J. Radioanal. 

Nucl. Chem. 299, 897 (2014).

Lindstrom, R.M., “The Half-Life of 111mPd,” J. Radioanal. 

Nucl. Chem. 300, 605 (2014).

Liu, D., Hussey, D.S., Gubarev, M.V., Ramsey, B.D., Jacobson, 

D., Arif, M., Moncton, D.E., Khaykovich, B., “Response to 

`Comment on `Demonstration of Achromatic Cold-Neutron 

Microscope Utilizing Axisymmetric Focusing mirrors,’’” 

Appl. Phys. Lett. 103, 236101 (2013).

Liu, D.X., Wang, J., Pan, K., Qiu, J., Canova, M., Cao, L.R., Co, 

A.C., “In Situ Quantification and Visualization of Lithium 

Transport with Neutrons,” Angew. Chem. Int. Ed., in press.

Liu, X., Majzoub, E.H., Stavila, V., Bhakta, R.K., Allendorf, M.D., 

Shane, D.T., Conradi, M.S., Verdal, N., Udovic, T.J., Hwang, 

S.-J., “Probing the Unusual Anion Mobility of LiBH4 Confined 

in Highly Ordered Nanoporous Carbon Frameworks via Solid 

State NMR and Quasielastic Neutron Scattering,” J. Mater. 

Chem. A 1, 9935 (2013). [CHRNS]

Liu, X., Trabold, T.A., Gagliardo, J.J., Jacobson, D.L., Hussey, D.S., 

“Neutron Imaging of Water Accumulation in the Active 

Area and Channel-to-Manifold Transitions of a PEMFC,” in 

“Proceedings of the ASME 2013 11th Fuel Cell Science,” 

(Engineering and Technology Conference, June 2013, 

Minneapolis, MN) (2013).

Liu, Y., “Colloidal Systems with Both a Short-Range Attraction 

and a Long-Range Repulsion,” Chem. Eng. Process, 1(2), 

1010 (2013). [CHRNS]

Livingston, R.A., Al-Sheikhly, M., Grissom, C., Aloiz, E., Paul, R., 

“Feasibility Study of Prompt Gamma Neutron Activation 

for NDT Measurement of Moisture in Stone and Brick,” 

AIP Conf. Proc. 1581, 828 (2014).

Lopes, T., Sansiñena, J.-M., Mukundan, R., Hussey, D.S., Jacobson, 

D.L., Garzon, F.H., “Diagnosing the Effects of Ammonia 

Exposure on PEFC Cathodes,” J. Electrochem. Soc. 161(6), 

F703 (2014).

López-Barrón, C.R., Gurnon, A.K., Eberle, A.P.R., Porcar, L., 

Wagner, N.J., “Microstructural Evolution of a Model, 

Shear-Banding Micellar Solution during Shear Startup 

and Cessation,” Phys. Rev. E 89(4), 042301 (2014).

Lott, J.R., McAllister, J.W., Wasbrough, M.J., Sammler, R.L., 

Bates, F.S., Lodge, T.P., “Fibrillar Structure in Aqueous 

Methylcellulose Solutions and Gels,” Macromolecules 46, 

9760 (2013). [CHRNS]

Lott, J.R., McAllister, J.W., Arvidson, S.A., Bates, F.S., Lodge, 

T.P., “Fibrillar Structure of Methylcellulose Hydrogels,” 

Biomacromolecules 14, 2484 (2013).

Lu, X., Tam, D.W., Zhang, C., Luo, H., Wang, M., Zhang, R., 

Harriger, L.W., Keller, T., Keimer, B., Regnault, L.-P., Maier, 

T.A., Dai, P., “Short-Range Cluster Spin Glass near Optimal 

Superconductivity in BaFe2-xNixAs2,” Phys. Rev. B 90(2), 

024509 (2014).

Lu, Z., Waldecker, J., Xie, X., Lai, M.-C., Hussey, D.S., Jacobson, 

D.L., “Investigation of Water Transport in Perforated Gas 

Diffusion Layer by Neutron Radiography,” ECS Transactions 

58(1), 315 (2013).

74 NIST CENTER FOR NEUTRON RESEARCH PUBLICATIONS
Luo, X., Ög ̆ üt, S., Yildirim, T., “Giant Charge Fluctuations with 

Se Height and Fe-Vacancy Formation in MxFe2-ySE2,” 

Phys. Rev. B 89(5), 054519 (2014).

Majkrzak, C.F., Metting, C., Maranville, B.B., Dura, J.A., Satija, 

S., Udovic, T., Berk, N.F., “Determination of the Effective 

Transverse Coherence of the Neutron Wave Packet as 

Employed in Reflectivity Investigations of CondensedMatter Structures. I. Measurements,” Phys. Rev. A 89(3), 

033851 (2014).

Majkrzak, C.F., Krycka, K., Krueger, S., Berk, N.F., Kienzle, P., 

Maranville, B., “Phase-Sensitive Small-Angle Neutron 

Scattering,” J. Appl. Crystallogr. 47, 780 (2014).

Mang, J.T., Francois, E.G., Hagelberg, S.I., “Compaction Properties 

of Diaminoazoxy Furazan (DAAF): A Small-Angle Neutron 

Scattering Study,” Int. J. Energetic Materials Chem. Prop. 

12(5), 411 (2013). [CHRNS]

Mang, J.T., Hjelm, R.P., “Fractal Networks of Inter-Granular Voids 

in Pressed TATB,” Propell. Explos. Pyrot. 38(6), 831 (2013). 

[CHRNS]

Manley, M.E., Jeffries, J.R., Lee, H., Butch, N.P., Zabalegui, A., 

Abernathy, D.L., “Multiple High-Temperature Transitions 

Driven by Dynamical Structures in NaI,” Phys. Rev. B 89(22), 

224106 (2014).

Manley, M.E., Lynn, J.W., Abernathy, D.L., Specht, E.D., Delaire, 

O., Bishop, A.R., Sahul, R., Budai, J.D., “Phonon Localization 

Drives Polar Nanoregions in a Relaxor Ferroelectric,” 

Nat. Commun. 5, 3683 (2014).

Matan, K., Nambu, Y., Zhao, Y., Sato, T.J., Fukumoto, Y., Ono, T., 

Tanaka, H., Broholm, C., Podlesnyak, A., Ehlers, G., “Ghost 

Modes and Continuum Scattering in the Dimerized Distorted 

Kagome Lattice Antiferromagnet Rb2Cu3SnF12,” Phys. Rev. B 

89(2), 024414 (2014).

McCabe, E.E., Stock, C., Rodriguez, E.E., Wills, A.S., Taylor, J.W., 

Evans, J.S.O., “Weak Spin Interactions in Mott Insulating 

La2O2Fe2OSe2,” Phys. Rev. B 89(10), 100402 (2014). [CHRNS]

McComb, J.C., Coplan, M.A., Al-Sheikhly, M., Thompson, A.K., 

Vest, R.E., Clark, C.W., “Noble Gas Excimer Scintillation 

Following Neutron Capture in Boron Thin Films,” J. Appl. 

Phys. 115(14), 144504 (2014).

Menéndez, E., Dias, T., Geshev, J., Lopez-Barbera, J.F., Nogués, 

J., Steitz, R., Kirby, B.J., Borchers, J.A., Pereira, L.M.C., 

Vantomme, A., Temst, K., “Interdependence between 

Training and Magnetization Reversal in Granular Co-CoO 

Exchange Bias Systems,” Phys. Rev. B 89(14), 144407 (2014).

Mildner, D.F.R., “Resolution of Small-Angle Neutron Scattering 

with a Reflective Focusing Optic,” J. Appl. Crystallogr., 

in press. [CHRNS]

Miller, C.W., Belyea, D.D., Kirby, B.J., “Magnetocaloric Effect in 

Nanoscale Thin Films and Heterostructures,” J. Vac. Sci. 

Technol. A 32(4), 040802 (2014).

Miskowiec, A., Buck, Z.N., Brown, M.C., Kaiser, H., Hansen, 

F.Y., King, G.M., Taub, H., Jiji, R., Cooley, J.W., Tyagi, 

M., Diallo, S.O., Mamontov, E., Herwig, K.W., “On the 

Freezing Behavior and Diffusion of Water in Proximity to 

Single-Supported Zwitterionic and Anionic Bilayer Lipid 

Membranes,” Europhys. Lett. 107, 28008 (2014). [CHRNS]

Mitkus, R.J., Powell, J.L., Zeisler, R., Squibb, K.S., “Comparative 

Physicochemical and Biological Characterization of NIST 

Interim Reference Material PM2.5 and SRM 1648 in Human 

A549 and Mouse RAW264.7 Cells,” Toxicol. in Vitro 27, 

2289 (2013).

Miyatsu, S., Kofu, M., Nagoe, A., Yamada, T., Sadakiyo, M., 

Yamada, T., Kitagawa, H., Tyagi, M., García Sakai, V., 

Yamamuro, O., “Proton Dynamics of Two-Dimensional 

Oxalate-Bridged Coordination Polymers,” Phys. Chem. 

Chem. Phys., in press. [CHRNS]

Monroe, J.G., Thompson, S.M., Aspin, Z.S., Jacobson, D., Hussey, 

D., “Neutron Imaging of an Unbalanced Flat-Plate Oscillating 

Heat Pipe,” in “52nd Aerospace Sciences Meeting,” (52nd 

Aerospace Sciences Meeting, January 2014, National Harbor, 

Maryland) (2014).

Moon, E.J., Balachandran, P.V., Kirby, B.J., Keavney, D.J., SichelTissot, R.J., Schlepütz, C.M., Karapetrova, E., Cheng, X.M., 

Rondinelli, J.M., May, S.J., “Effect of Interfacial Octahedral 

Behavior in Ultrathin Manganite Films,” Nano Lett. 14, 

2509 (2014).

Mourigal, M., Fuhrman, W.T., Sheckelton, J.P., Wartelle, A., 

Rodriguez-Rivera, J.A., Abernathy, D.L., McQueen, 

T.M., Broholm, C.L., “Molecular Quantum Magnetism 

in LiZn2Mo3O8,” Phys. Rev. Lett. 112(2), 027202 (2014). 

[CHRNS]

Nagaraja, A.R., Stone, K.H., Toney, M.F., Peng, H., Lany, S., Mason, 

T.O., “Experimental Characterization of a Theoretically 

Designed Candidate p-Type Transparent Conducting Oxide: 

Li-Doped Cr2MnO4,” Chem. Mater., in press.

Nagpure, S.C., Mulligan, P., Canova, M., Cao, L.R., “Neutron 

Depth Profiling of Li-Ion Cell Electrodes with a 

Gas-Controlled Environment,” J. Power Sources 248, 

489 (2014).

Nagpure, S.C., Bhushan, B., Babu, S.S., “Multi-Scale 

Characterization Studies of Aged Li-Ion Large Format Cells 

for Improved Performance: An Overview,” J. Electrochem. 

Soc. 160(11), A2111 (2013).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 75PUBLICATIONS
Nelson, A.R.J., “Towards a Detailed Resolution Smearing Kernel 

for Time-of-Flight Neutron Reflectometers,” J. Appl. 

Crystallogr. 46, 1338 (2013).

Newman, C., Zhou, X., Goundie, B., Ghampson, I.T., Pollock, 

R.A., Ross, Z., Wheeler, M.C., Meulenberg, R.W., Austin, 

R.N., Frederick, B.G., “Effects of Support Identity and Metal 

Dispersion in Supported Ruthenium Hydrodeoxygenation 

Catalysts,” Appl. Catal. A-Gen. 477, 64 (2014).

Nickels, J.D., “Instrumental Resolution Effects in Neutron 

Scattering Studies of Protein Dynamics,” Chem. Phys. 

424, 7 (2013). [CHRNS]

Nickels, J.D., García Sakai, V., Sokolov, A.P., “Dynamics in Protein 

Powders on the Nanosecond-Picosecond Time Scale are 

Dominated by Localized Motions,” J. Phys. Chem. B 117, 

11548 (2013). [CHRNS]

Nozaki, Y., Nakano, K., Yajima, T., Kageyama, H., Frandsen, B., 

Liu, L., Cheung, S., Goko, T., Uemura, Y.J., Munsie, T.S.J., 

Medina, T., Luke, G.M., Munevar, J., Nishio-Hamane, D., 

Brown, C.M., “Muon Spin Relaxation and Electron/Neutron 

Diffraction Studies of BaTi2(As1-xSbx)2O: Absence of Static 

Magnetism and Superlattice Reflections,” Phys. Rev. B 

88(21), 214506 (2013).

Olsson, A., Hellsing, M.S., Rennie, A.R., “A Holder to Rotate 

Sample Cells to Avoid Sedimentation in Small-Angle Neutron 

Scattering and Ultra Small-Angle Neutron Scattering 

Experiments,” Meas. Sci. Technol. 24, 105901 (2013). 

[CHRNS]

Owejan, J.P., Trabold, T.A., Mench, M.M., “Oxygen Transport 

Resistance Correlated to Liquid Water Saturation in the Gas 

Diffusion Layer of PEM Fuel Cells,” Int. J. Heat. Mass Tran. 

71, 585 (2014).

Page, K.A., Rowe, B.W., Masser, K.A., Faraone, A., “The 

Effect of Water Content on Chain Dynamics in Nafion 

Membranes Measured by Neutron Spin Echo and Dielectric 

Spectroscopy,” J. Polym. Sci. Pol. Phys. 52, 624 (2014). 

[CHRNS]

Pajerowski, D.M., Ravel, B., Li, C.H., Dumont, M.F., Talham, 

D.R., “X-ray Absorption Study of Structural Coupling 

in Photomagnetic Prussian Blue Analogue Core@Shell 

Particles,” Chem. Mater. 26, 2586 (2014).

Pajerowski, D.M., Li, Q., Hyun, J., Dennis, C.L., Phelan, D., Yan, P., 

Chen, P., Li, G., “Chloride-Bridged, Defect-Dicubane {Ln4} 

Core Clusters: Syntheses, Crystal Structures and Magnetic 

Properties,” Dalton T., in press.

Pang, D., Nico, J.S., Karam, L., Timofeeva, O., Blakely, W.F., 

Dritschilo, A., Dizdaroglu, M., Jaruga, P., “Significant 

Disparity in Base and Sugar Damage in DNA Resulting from 

Neutron and Electron Irradiation,” J. Radiat. Res., in press.

Pangelis, S., Olsen, S.R., Scherschligt, J., Leão, J.B., Pullen, S.A., 

Dender, D., Hester, J.R., Imperia, P., “Safety Interlock and 

Vent System to Alleviate Potentially Dangerous Ice Blockage 

of Top-loading Cryostat Sample Sticks,” J. Appl. Crystallogr. 

46(4), 1236 (2013). [CHRNS]

Parshall, D., Heid, R., Niedziela, J.L., Wolf, Th., Stone, M.B., 

Abernathy, D.L., Reznik, D., “Phonon Spectrum of SrFe2As2

Determined using Multizone Phonon Refinement,” 

Phys. Rev. B 89(6), 064310 (2014).

Parsons, M.S., “SIDecSo, A Simple Analytic Software for Neutron 

Depth Profiling, Invited,” in “Transactions of the American 

Nuclear Society,” (Developments and Applications of 

Neutron Beam Techniques, November 2013, Washington, 

D.C.) 109, 525 (2013).

Patterson, J.P., Kelley, E.G., Murphy, R.P., Moughton, A.O., Robin, 

M.P., Lu, A., Colombani, O., Chassenieux, C., Cheung, 

D., Sullivan, M.O., Epps, III, T.H., O’Reilly, R.K., “Structural 

Characterization of Amphiphilic Homopolymer Micelles using 

Light Scattering, SANS, and Cryo-TEM,” Macromolecules 

46, 6319 (2013).

Paul, R.L., Davis, W.C., Yu, L., Murphy, K.E., Guthrie, W.F., Leber, 

D.D., Bryan, C.E., Vetter, T.W., Shakirova, G., Mitchell, G., 

Kyle, D.J., Jarrett, J.M., Caldwell, K.L., Jones, R.L., Eckdahl, 

S., Wermers, M., Maras, M., Palmer, C.D., Verostek, M.F., 

Geraghty, C.M., Steuerwald, A.J., Parsons, P.J., “Certification 

of Total Arsenic in Blood and Urine Standard Reference 

Materials by Radiochemical Neutron Activation Analysis 

and Inductively Coupled Plasma-Mass Spectrometry,” J. 

Radioanal. Nucl. Chem. 299, 1555 (2014).

Paul, R.L., “Determination of Arsenic in Food and Dietary 

Supplement Standard Reference Materials by Neutron 

Activation Analysis,” J. Radioanal. Nucl. Chem. 297, 

365 (2013).

Pena-Francesch, A., Akgun, B., Miserez, A., Zhu, W., Gao, 

H., Demirel, M.C., “Pressure Sensitive Adhesion of an 

Elastomeric Protein Complex Extracted from Squid 

Ring Teeth,” Adv. Funct. Mater., in press.

Peng, Y., Krungleviciute, V., Eryazici, I., Hupp, J.T., Farha, O.K., 

Yildirim, T., “Methane Storage in Metal-Organic Frameworks: 

Current Records, Surprise Findings, and Challenges,” 

J. Am. Chem. Soc. 135(32), 11887 (2013).

Pesek, S.L., Li, X., Hammouda, B., Hong, K., Verduzco, R., 

“Small-Angle Neutron Scattering Analysis of Bottlebrush 

Polymers Prepared via Grafting-Through Polymerization,” 

Macromolecules 46, 6998 (2013). [CHRNS]

Phelan, D., Bhatti, K.P., Taylor, M., Wang, S., Leighton, C., 

“Magnetically Inhomogeneous Ground State Below the 

First-Order Valence Transition in (Pr1-yYy)0.7Ca0.3CoO3-δ,” 

Phys. Rev. B 89(18), 184427 (2014). [CHRNS]

76 NIST CENTER FOR NEUTRON RESEARCH PUBLICATIONS
Phelan, D., Suzuki, Y., Wang, S., Huq, A., Leighton, C., “Structural, 

Transport, and Magnetic Properties of Narrow Bandwidth 

Nd1-xCaxCoO3-δ and Comparisons to Pr1-xCaxCoO3-δ” 

Phys. Rev. B 88(7), 075119 (2013). [CHRNS]

Phelan, D., “Constraints on the Possible Long-Range Orbital 

Ordering in LaCoO3,” J. Magn. Magn. Mater. 350, 

183 (2014).

Phelan, D., Stock, C., Rodriguez-Rivera, J.A., Chi, S., Leão, J., Long, 

X., Xie, Y., Bokov, A.A., Ye, Z.-G., Ganesh, P., Gehring, P.M., 

“Role of Random Electric Fields in Relaxors,” P. Natl. A. Sci. 

USA 111(5), 1754 (2014). [CHRNS]

Pintschovius, L., Reznik, D., Weber, F., Bourges, P., Parshall, D., 

Mittal, R., Chaplot, S.L., Heid, R., Wolf, T., Lamago, D., 

Lynn, J.W., “Spurious Peaks Arising from Multiple Scattering 

Events Involving the Sample Environment in Inelastic Neutron 

Scattering,” J. Appl. Crystallogr., in press.

Pollock, R.A., Her, J.-H., Brown, C.M., Liu, Y., Dailly, A., “Kinetic 

Trapping of D2 in MIL-53(Al) Observed using Neutron 

Scattering,” J. Phys. Chem. C, in press.

Pulido, R., Baker, S.J., Barata, J.T., Carracedo, A., Cid, V.J., ChinSang, I.D., Davé, V., den Hertog, J., Devreotes, P., Eickholt, 

B.J., Eng, C., Furnari, F.B., Georgescu, M.-M., Gericke, A., 

Hopkins, B., Jiang, X., Lee, S.-R., Lösche, M., Malaney, P., 

Matias-Guiu, X., Molina, M., Pandolfi, P.P., Parsons, R., 

Pinton, P., Rivas, C., Rocha, R.M., Rodríguez, M.S., Ross, 

A.H., Serrano, M., Stambolic, V., Stiles, B., Suzuki, A., Tan, 

S.-S., Tonks, N.K., Trotman, L.C., Wolff, N., Woscholski, R., 

Wu, H., Leslie, N.R., “A Unified Nomenclature and Amino 

Acid Numbering for Human PTEN,” Science Signaling 7(332), 

pe15 (2014).

Queen, W.L., Lee, J., Gonzalez, M., Geier, S.J., Mason, J.A., 

Long, J.R., Brown, C.M., Hudson, M.R., Teat, S.J., 

“Correlations between Structure and Gas-Adsorption/

Separation Properties of Metal-Organic Frameworks,” 

T. Am. Crystallogr. Assn. 44, 120 (2014).

Quinn, G.D., Zilcha, O., Rowe, J.M., Pierce, D.J., “Failure Analysis 

of a 41-m Long Neutron Beam Line Guide,” J. Eur. Ceram. 

Soc., in press.

Quiquandon, M., Gratias, D., “About the Atomic Structures 

of Icosahedral Quasicrystals,” C. R. Phys. 15, 18 (2014).

Rao, X., Cai, J., Yu, J., He, Y., Wu, C., Zhou, W., Yildirim, T., Chen, 

B., Qian, G., “A Microporous Metal-Organic Framework with 

Both Open Metal and Lewis Basic Pyridyl Sites for High C2H2

and CH4 Storage at Room Temperature,” Chem. Commun. 

49(60), 6719 (2013).

Ratcliff, II, W., “Reflections on the Magnetic Pair Distribution 

Function,” Acta Crystallogr. A A70, 1 (2014).

Rennie, A.R., Hellsing, M.S., Wood, K., Gilbert, E.P., Porcar, L., 

Schweins, R., Dewhurst, C.D., Lindner, P., Heenan, R.K., 

Rogers, S.E., Butler, P.D., Krzywon, J.R., Ghosh, R.E., Jackson, 

A.J., Malfois, M., “Learning about SANS Instruments and 

Data Reduction from Round Robin Measurements on 

Samples of Polystyrene Latex,” J. Appl. Crystallogr. 46, 

1289 (2013).

Richards, J.J., Whittle, C.L., Shao, G., Pozzo, L.D., “Correlating 

Structure and Photocurrent for Composite Semiconducting 

Nanoparticles with Contrast Variation Small-Angle Neutron 

Scattering and Photoconductive Atomic Force Microscopy,” 

ACS Nano 8(5), 4313 (2014). [CHRNS]

Rodriguez, E.E., Sokolov, D.A., Stock, C., Green, M.A., Sobolev, 

O., Rodriguez-Rivera, J.A., Cao, H., Daoud-Aladine, A., 

“Magnetic and Structural Properties near the Lifshitz Point 

in Fe1+xTe,” Phys. Rev. B 88(16), 165110 (2013). [CHRNS]

Roh, J.H., Tyagi, M., Hogan, T.E., Roland, C.M., “Effect of Binding 

to Carbon Black on the Dynamics of 1,4-Polybutadiene,” 

J. Chem. Phys. 139(13), 134905 (2013). [CHRNS]

Roh, J.H., Tyagi, M., Hogan, T.E., Roland, C.M., “SpaceDependent Dynamics in 1,4-Polybutadiene Nanocomposite,” 

Macromolecules 46, 6667 (2013). [CHRNS]

Ross, K.A., Qiu, Y., Copley, J.R.D., Dabkowska, H.A., Gaulin, B.D., 

“Order by Disorder Spin Wave Gap in the XY Pyrochlore 

Magnet Er2Ti2O7,” Phys. Rev. Lett. 112(5), 057201 (2014). 

[CHRNS]

Ross, K.A., Harriger, L., Yamani, Z., Buyers, W.J.L., Garrett, J.D., 

Menovsky, A.A., Mydosh, J.A., Broholm, C.L., “Strict Limit 

on In-Plane Ordered Magnetic Dipole Moment in URu2Si2,” 

Phys. Rev. B 89(15), 155122 (2014).

Rubinson, K.A., “Small-Angle Neutron Scattering of Aqueous 

SrI2 Suggests a Mechanism for Ion Transport in Molecular 

Water,” J. Solution Chem. 43, 453 (2014). [CHRNS]

Sadakane, K., Nagao, M., Endo, H., Seto, H., “Membrane 

Formation by Preferential Solvation of Ions in Mixture of 

Water, 3-Methylpyridine, and Sodium Tetraphenylborate,” 

J. Chem. Phys. 139(23), 234905 (2013). [CHRNS]

Saffer, E.M., Lackey, M.A., Griffin, D.M., Kishore, S., Tew, G.N., 

Bhatia, S.R., “SANS Study of Highly Resilient Poly(Ethylene 

Glycol) Hydrogels,” Soft Matter 10, 1905 (2014).

Saha, S.R., Drye, T., Goh, S.K., Klintberg, L.E., Silver, J.M., Grosche, 

F.M., Sutherland, M., Munsie, T.J.S., Luke, G.M., Pratt, D.K., 

Lynn, J.W., Paglione, J., “Segregation of Antiferromagnetism 

and High-Temperature Superconductivity in Ca1-xLaxFe2As2,” 

Phys. Rev. B 89(13), 134516 (2014).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 77PUBLICATIONS
S ̧ ahin, D., Radulovic ́, V., Lindstrom, R.M., Trkov, A., “Reevaluation 

of Neutron Flux Characterization Parameters for NIST RT-2 

Facility,” J. Radioanal. Nucl. Chem. 300, 499 (2014).

Saparov, B., Cantoni, C., Pan, M., Hogan, T.C., Ratcliff, II, W., 

Wilson, S.D., Fritsch, K., Gaulin, B.D., Sefat, A.S., “Complex 

Structures of Different CaFe2As2 Samples,” Sci. Rep. 4, 

4120 (2014).

Sarachan, K.L., Curtis, J.E., Krueger, S., “Small-Angle Scattering 

Contrast Calculator for Protein and Nucleic Acid Complexes 

in Solution,” J. Appl. Crystallogr. 46, 1889 (2013).

Seibel, E.M., Roudebush, J.H., Wu, H., Huang, Q., Ali, M.N., Ji, 

H., Cava, R.J., “Structure and Magnetic Properties of the 

α-NaFeO2-Type Honeycomb Compound Na3Ni2BiO6,” 

Inorg. Chem. 52, 13605 (2013).

Shen, H., Zhang, W., Mackay, M.E., “Dual Length Morphological 

Model for Bulk-Heterojunction Polymer-Based Solar Cells,” 

J. Polym. Sci. Pol. Phys. 52, 387 (2014). [CHRNS]

Silverstein, H.J., Fritsch, K., Flicker, F., Hallas, A.M., Gardner, 

J.S., Qiu, Y., Ehlers, G., Savici, A.T., Yamani, Z., Ross, K.A., 

Gaulin, B.D., Gingras, M.J.P., Paddison, J.A.M., Foyevtsova, 

K., Valenti, R., Hawthorne, F., Wiebe, C.R., Zhou, H.D., 

“Liquidlike Correlations in Single-Crystalline Y2Mo2O7: An 

Unconventional Spin Glass,” Phys. Rev. B 89(5), 054433 

(2014). [CHRNS]

Simmons, J.M., Cook, J.C., Ibberson, R.M., Majkrzak, C.F., 

Neumann, D.A., “Polychromatic Energy-Dispersive Neutron 

Diffraction at a Continuous Source,” J. Appl. Crystallogr. 

46, 1347 (2013).

Singh, D.K., “Interplay of Spin Gap and Nanoscopic Quantum 

Fluctuations in Intermetallic CeCu2Ge2,” Phys. Lett. A 378, 

1906 (2014).

Sinha, K., Maranas, J., “Does Ion Aggregation Impact Polymer 

Dynamics and Conductivity in PEO-Based Single Ion 

Conductors?” Macromolecules 47, 2718 (2014). [CHRNS]

Skowronek, R.K., Blackman, M.J., Bishop, R.L., “Ceramic 

Production in Early Hispanic California”, (University Press 

of Florida, Gainesville, Florida) (2014).

Skowronek, R.K., Blackman, M.J., Bishop, R.L., “Ceramic 

Production in Early Hispanic California: Craft, Economy, 

and Trade on the Frontier of New Spain,” in press.

Skripov, A.V., Paul-Bancour, V., Udovic, T.J., Rush, J.J., “Hydrogen 

Dynamics in Laves-Phase Hydride YFe2H2.6: Inelastic and 

Quasielastic Neutron Scattering Studies,” J. Alloy Compd. 

595, 28 (2014). [CHRNS]

Skripov, A.V., Babanova, O.A., Soloninin, A.V., Stavila, V., Verdal, 

N., Udovic, T.J., Rush, J.J., “Nuclear Magnetic Resonance 

Study of Atomic Motions in A2B12H12 (A = Na, K, Rb, Cs): 

Anion Reorientations and Na+ Mobility,” J. Phys. Chem. C 

117, 25961 (2013).

Smoot, C.D., Ma, H.B., Winholtz, R.A., Jacobson, D.L., Hussey, 

D.S., “Thermal and Visual Observation of a Hybrid Heat 

Pipe,” Heat Transf. Res. 44(1), 31 (2013).

Soh, J.H., Tucker, G.S., Pratt, D.K., Abernathy, D.L., Stone, 

M.B., Ran, S., Bud’Ko, S.L., Canfield, P.C., Kreyssig, A., 

McQueeny, R.J., Goldman, A.I., “Inelastic Neutron Scattering 

Study of a Nonmagnetic Collapsed Tetragonal Phase in 

Nonsuperconducting CaFe2As2: Evidence of the Impact of 

Spin Fluctuations on Superconductivity in the Iron-Arsenide 

Compounds,” Phys. Rev. Lett. 111(22), 227002 (2013).

Sokolov, D.A., Aronson, M.C., Wu, L., Zhu, Y., Nelson, C., 

Mansfield, J.F., Sun, K., Erwin, R., Lynn, J.W., Lumsden, 

M., Nagler, S.E., “Neutron, Electron, and X-ray Scattering 

Investigation of Cr1-xVx Near Quantum Criticality,” 

Phys. Rev. B 90(3), 035139 (2014).

Srinivas, G., Krungleviciute, V., Guo, Z.-X., Yildirim, T., “Exceptional 

CO2 Capture in a Hierarchically Porous Carbon with 

Simultaneous High Surface Area and Pore Volume,” 

Energ. Environ. Sci. 7, 335 (2014).

Stalick, J.K., Waterstrat, R.M., “The Hafnium-Platinum Phase 

Diagram,” J. Phase Equilib. Diff. 35(1), 15 (2014).

Subramanian, D., Boughter, C.T., Klauda, J.B., Hammouda, B., 

Anisimov, M.A., “Mesoscale Inhomogeneities in Aqueous 

Solutions of Small Amphiphilic Molecules,” Faraday Discuss. 

167, 217 (2013). [CHRNS]

Swain, M., Singh, S., Basu, S., Gupta, M., “Effect of Interface 

Morphology on Intermetallics Formation Upon Annealing 

of Al-Ni Multilayer,” J. Alloy Compd. 576, 257 (2013).

Takatsu, H., Nénert, G., Kadowaki, H., Yoshizawa, H., Enderle, 

M., Yonezawa, S., Maeno, Y., Kim, J., Tsuji, N., Takata, M., 

Zhao, Y., Green, M., Broholm, C., “Magnetic Structure of 

the Conductive Triangular-Lattice Antiferromagnet PdCrO2,” 

Phys. Rev. B 89(10), 104408 (2014).

Tao, R., Du, E., Tang, H., Xu, X., “Neutron Scattering Studies of 

Crude Oil Viscosity Reduction with Electric Field,” Fuel, in 

press.

Tassel, C., Goto, Y., Kuno, Y., Hester, J., Green, M., Kobayashi, Y., 

Kageyama, H., “Direct Synthesis of Chromium Perovskite 

Oxyhydride with a High Magnetic-Transition Temperature,” 

Angew. Chem. Int. Ed., in Press.

78 NIST CENTER FOR NEUTRON RESEARCH PUBLICATIONS
Thomas, J.J., Musso, S., Prestini, I., “Kinetics and Activation Energy 

of Magnesium Oxide Hydration,” J. Am. Ceram. Soc. 97(1), 

275 (2014). [CHRNS]

Thomas, J.J., Valenza, II, J.J., Craddock, P.R., Bake, K.D., 

Pomerantz, A.E., “The Neutron Scattering Length Density 

of Kerogen and Coal as Determined by CH3OH/CD3OH 

Exchange,” Fuel 117, 801 (2014).

Turk, G.C., Sharpless, K.E., Cleveland, D., Jongsma, C., Mackey, 

E.A., Marlow, A.F., Oflaz, R., Paul, R.L., Sieber, J.R., 

Thompson, R.Q., Wood, L.J., Yu, L.L., Zeisler, R., Wise, S.A., 

Yen, J.H., Christopher, S.J., Day, R.D., Long, S.E., Greene, E., 

Harnly, J., Ho, I.-P., Betz, J.M., “Certification of Elements in 

and Use of Standard Reference Material 3280 Multivitamin/

Multielement Tablets,” J. AOAC Int. 96(6), 1281 (2013).

Turkoglu, D., Glover, S., Spitz, H., Cao, L., “Applying Method of 

Integral Thermal Neutron Cross-Section Measurement using 

Activated Prompt Gamma Rays to Non-1/ν Isotopes,” T. Am. 

Nucl. Soc. 109, 118 (2013).

Udovic, T.J., Verdal, N., Rush, J.J., De Vries. D.J., Hartman, M.R., 

Vajo, J.J., Gross, A.F., Skripov, A.V., “Mapping Trends in the 

Reorientational Mobilities of Tetrahydroborate Anions via 

Neutron-Scattering Fixed-Window Scans,” J. Alloy Compd. 

580, S47 (2013). [CHRNS]

Udovic, T.J., Matsuo, M., Unemoto, A., Verdal, N., Stavila, V., 

Skripov, A.V., Rush, J.J., Takamura, H., Orimo, S.-I., “Sodium 

Superionic Conduction in Na2B12H12,” Chem. Commun. 50, 

3750 (2014).

Ueland, B.G., Kreyssig, A., Prokeš, K., Lynn, J.W., Harriger, L.W., 

Pratt, D.K., Singh, D.K., Heitmann, T.W., Sauerbrei, S., 

Saunders, S.M., Mun, E.D., Bud’ko, S.L., McQueeney, R.J., 

Canfield, P.C., Goldman, A.I., “Fragile Antiferromagnetism in 

the Heavy-Fermion Compound YbBiPt,” Phys. Rev. B 89(18), 

180403 (2014).

Vaish, A., Vanderah, D.J., Vierling, R., Crawshaw, F., Gallagher, 

D.T., Walker, M.L., “Membrane Protein Resistance of 

Oligo(ethylene oxide) Self-Assembled Monolayers,” 

Colloid Surface. B, in press.

Valadez-Pérez, N.E., Castañeda-Priego, R., Liu, Y., “Percolation in 

Colloidal Systems with Competing Interactions: The Role of 

Long-Range Repulsion,” RSC Adv. 3, 25110 (2013).

Valadez-Pérez, N.E., Liu, Y., Eberle, A.P.R., Wagner, N.J., 

Castañeda-Priego, R., “Dynamical Arrest in Adhesive 

Hard-Sphere Dispersions Driven by Rigidity Percolation,” 

Phys. Rev. E 88(6), 060302 (2013).

Verdal, N., Udovic, T.J., Stavila, V., Tang, W.S., Rush, J.J., Skripov, 

A.V., “Anion Reorientations in the Superionic Conducting 

Phase of Na2B12H12,” J. Phys. Chem. C, in press. [CHRNS]

Verdal, N., Udovic, T.J., Rush, J.J., Liu, X., Majzoub, E.H., Vajo, J.J., 

Gross, A.F., “Dynamical Perturbations of Tetrahydroborate 

Anions in LiBH4 due to Nanoconfinement in Controlled-Pore 

Carbon Scaffolds,” J. Phys. Chem. C 117, 17983 (2013). 

[CHRNS]

Verdal, N., Her, J.-H., Stavila, V., Soloninin, A.V., Babanova, 

O.A., Skripov, A.V., Udovic, T.J., Rush, J.J., “Complex HighTemperature Phase Transitions in Li2B12H12 and Na2B12H12,”

 J. Solid State Chem. 212, 81 (2014). [CHRNS]

Verploegen, E., Sokolov, A.N., Akgun, B, Satija, S.K., Wei, P., 

Kim, D., Kapelewski, M.T., Bao, Z., Toney, M.F., “Swelling of 

Polymer Dielectric Thin Films for Organic-Transistor-Based 

Aqueous Sensing Applications,” Chem. Mater. 25, 5018 

(2013).

von Bardeleben, H.J., Cantin, J.L., Zhang, D.M., Richardella, A., 

Rench, D.W., Samarth, N., “Ferromagnetism in Bi2Se3: Mn 

Epitaxial Layers,” Phys. Rev. B 88(7), 075149 (2013).

Wallace, D.C., Brown, C.M., McQueen, T.M., “Evolution of 

Magnetism in the Na3-δ(Na1-xMgx)Ir2O6 Series of 

Honeycomb Iridates,” J. Solid State Chem., in press.

Wang, C.-W., Lee, C.-H., Li, C.-Y., Wu, C.-M., Li, W.-H., Chou, 

C.-C., Yang, H.-D., Lynn, J.W., Huang, Q., Harris, A.B., 

Berger, H., “Complex Magnetic Couplings in Co3TeO6,” 

Phys. Rev. B 88(18), 184427 (2013).

Wang, D., Hore, M.J.A., Ye, X., Zheng, C., Murray, C.B., 

Composto, R.J., “Gold Nanorod Length Controls Dispersion, 

Local Ordering, and Optical Absorption in Polymer 

Nanocomposite Films,” Soft Matter 10, 3404 (2014).

Wang, H.-W., Anovitz, L.M., Burg, A., Cole, D.R., Allard, 

L.F., Jackson, A.J., Stack, A.G., Rother, G., “Multi-scale 

Characterization of Pore Evolution in a Combustion 

Metamorphic Complex, Hatrurim Basin, Israel: Combining 

(ultra) Small-Angle Neutron Scattering and Image Analysis,” 

Geochim. Cosmochim. Ac. 121, 339 (2013). [CHRNS]

Wang, J., Liu, D.X., Canova, M., Downing, R.G., Cao, L.R., 

Co, A.C., “Profiling Lithium Distribution in Sn Anode for 

Lithium-ion Batteries with Neutrons,” J. Radioanal. Nucl. 

Chem. 301, 277 (2014).

Wang, S.-F., Yang, S., Lee, J., Akgun, B., Wu, D.T., Foster, M.D., 

“Anomalous Surface Relaxations of Branched-Polymer 

Melts,” Phys. Rev. Lett. 111(6), 068303 (2013).

Wang, Z., Liu, K.-H., Le, P., Li, M., Chiang, W.-S., Leão, J.B., Copley, 

J.R.D., Tyagi, M., Podlesnyak, A., Kolesnikov, A.I., Mou, C.-Y., 

Chen, S.-H., “Boson Peak in Deeply Cooled Confined Water: 

A Possible Way to Explore the Existence of the Liquid-toLiquid Transition in Water,” Phys. Rev. Lett. 112(23), 237802 

(2014). [CHRNS]

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 79PUBLICATIONS
Wang, Z., Liu, K.-H., Harriger, L., Leão, J.B., Chen, S.-H., 

“Evidence of the Existence of the High-Density and 

Low-Density Phases in Deeply-Cooled Confined Heavy Water 

under High Pressures,” J. Chem. Phys. 141(1), 014501 (2014).

Watson, M.C., Curtis, J.E., “Rapid and Accurate Calculation of 

Small-Angle Scattering Profiles using the Golden Ratio,” 

J. Appl. Crystallogr. 46(4), 1171 (2013).

Watson, M.C., Morriss-Andrews, A., Welch, P.M., Brown, F.L.H., 

“Thermal Fluctuations in Shape, Thickness, and Molecular 

Orientation in Lipid Bilayers. II. Finite Surface Tensions,” 

J. Chem. Phys. 139(8), 084706 (2013).

Watson, M.C., Curtis, J.E., “Probing the Average Local Structures 

of Biomolecules using Small-Angle Scattering and Scaling 

Laws,” Biophys. J. 106, 2474 (2014).

Weinrich, M., Worcester, D.L., “Xenon and Other Volatile 

Anesthetics Change Domain Structure in Model Lipid Raft 

Membranes,” J. Phys. Chem. B 117, 16141 (2013).

Wen, H.-M., Li, B., Yuan, D., Wang, H., Yildirim, T., Zhou, W., 

Chen, B., “A Porous Metal-Organic Framework with an 

Elongated Anthracene Derivative Exhibiting a High Working 

Capacity for the Storage of Methane,” J. of Mater. Chem. 

A 2, 11516 (2014).

White, J.S., Niedermayer, Ch., Gasparovic, G., Broholm, C., Park, 

J.M.S., Shapiro, A.Ya., Demianets, L., Kenzelmann, M., 

“Multiferroicity in the Generic Easy-Plane Triangular Lattice 

Antiferromagnet RbFe(MoO4)2,” Phys. Rev. B 88(6), 

060409 (2013).

Wietfeldt, F.E., Darius, G., Dewey, M.S., Fomin, N., Greene, G.L., 

Mulholland, J., Snow, W.M., Yue, A.T., “A Path to a 0.1 s 

Neutron Lifetime Measurement using the Beam Method,” 

Physics Procedia 51, 54 (2014).

Wong-Ng, W., Laws, W., Talley, K.R., Huang, Q., Yan, Y., Martin, 

J., Kaduk, J.A., “Phase Equilibria and Crystal Chemistry of the 

CaO-1/2 Nd2O3-CoOz system at 885 °C in Air,” J. Solid State 

Chem. 215, 128 (2014).

Wood, B.M., Ham, K., Hussey, D.S., Jacobson, D.L., Faridani, A., 

Kaestner, A., Vajo, J.J., Liu, P., Dobbins, T.A., Butler, L.G., 

“Real-Time Observation of Hydrogen Absorption by LaNi5

with Quasi-Dynamic Neutron Tomography,” Nucl. Instrum. 

Meth. B 324, 95 (2014).

Wu, M., Wang, C., Sun, Y., Chu, L., Yan, J., Chen, D., Huang, Q., 

Lynn, J.W., “Magnetic Structure and Lattice Contraction in 

Mn3NiN,” J. Appl. Phys. 114(12), 123902 (2013).

Xiao, D.J., Bloch, E.D., Mason, J.A., Queen, W.L, Hudson, M.R., 

Planas, N., Borycz, J., Dzubak, A.L., Verma, P., Lee, K., 

Bonino, F., Crocellà, V., Yano, J., Bordiga, S., Truhlar, D.G., 

Gagliardi, L., Brown, C.M., Long, J.R., “Oxidation of Ethane 

to Ethanol by N2O in a Metal-Organic Framework with 

Coordinatively Unsaturated Iron(II) Sites,” Nat. Chem. 6, 

590 (2014).

Xu, J., Yang, B., Hammouda, B., “Thermophysical Properties and 

Pool Boiling Characteristics of Water-in-Polyalphaolefin 

Nanoemulsion Fluids,” J. Heat Transf. 135, 091303 (2013). 

[CHRNS]

Xu, J., Wang, X., Fu, H., Brown, C.M., Jing, X., Liao, F., Lu, F., Li, 

X., Kuang, X., Wu, M., “Solid-State 29Si NMR and NeutronDiffraction Studies of Sr0.7K0.3SiO2.85 Oxide Ion Conductors,” 

Inorg. Chem. 53, 6962 (2014).

Yajima, T., Takeiri, F., Nozaki, Y., Li, Z., Tohyama, T., Green, M.A., 

Kobayashi, Y., Kageyama, H., “Superconductivity in the 

Hypervalent Compound Ba2Bi(Sb1-xBix)2 with a SquareHoneycomb Lattice,” J. Phys. Soc. Jpn. 83, 073705 (2014).

Yamada, T., Yamada, T., Tyagi, M., Nagao, M., Kitagawa, H., 

Yamamuro, O., “Phase Transition and Dynamics of Water 

Confined in Hydroxyethyl Copper Rubeanate Hydrate,” J. 

Phys. Soc. Jpn. 82, SA010 (2013). [CHRNS]

Yan, J., Sun, Y., Wu, H., Huang, Q., Wang, C., Shi, Z., Deng, S., Shi, 

K., Lu, H., Chu, L., “Phase Transitions and Magnetocaloric 

Effect in Mn3Cu0.89N0.96,” Acta Mater., in press.

Yan, J., Sun, Y., Wen, Y., Chu, L., Wu, M., Huang, Q., Wang, C., 

Lynn, J.W., Chen, Y., “Relationship between Spin Ordering, 

Entropy, and Anomalous Lattice Variation in Mn3Sn1-εSiεC1-δ

Compounds,” Inorg. Chem. 53, 2317 (2014).

Yang, K., Tyagi, M., Moore, J.S., Zhang, Y., “Odd-Even Glass 

Transition Temperatures in Network-Forming Ionic Glass 

Homologue,” J. Am. Chem. Soc. 136, 1268 (2014). [CHRNS]

Yang, X., Downing, R.G., Wang, G.-B., Qian, D.-Z., Liu, H.-G., 

Wang, K., “A Monte Carlo Code to Get Response Spectrum 

of Ions for Neutron Depth Profiling,” J. Radioanal. Nucl. 

Chem. 301(1), 213 (2014).

Yang, Y., Liu, Y., Wu, H., Zhou, W., Gao, M., Pan, H., “An 

Ammonia-Stabilized Mixed-Cation Borohydride: Synthesis, 

Structure and Thermal Decomposition Behavior,” Phys. 

Chem. Chem. Phys. 16, 135 (2014).

Yano, S.-I., Louca, D., Chi, S., Matsuda, M., Qiu, Y., Copley, J.R.D., 

Cheong, S.-W., “Intertwining of Frustration with MagnetoElastic Coupling in the Multiferroic LuMnO3,” J. Phys. Soc. 

Jpn. 83, 024601 (2013). [CHRNS]

80 NIST CENTER FOR NEUTRON RESEARCH PUBLICATIONS
Yearley, E.J., Zarraga, I.E., Shire, S.J., Scherer, T.M., Gokarn, Y., 

Wagner, N.J., Liu, Y., “Small-Angle Neutron Scattering 

Characterization of Monoclonal Antibody Conformations 

and Interactions at High Concentrations,” Biophys. J. 

105, 720 (2013). [CHRNS]

Yearley, E.J., Godfrin, P.D., Perevozchikova, T., Zhang, H., Falus, 

P., Porcar, L., Nagao, M., Curtis, J.E., Gawande, P., Taing, R., 

Zarraga, I.E., Wagner, N.J., Liu, Y., “Observation of Small 

Cluster Formation in Concentrated Monoclonal Antibody 

Solutions and Its Implications to Solution Viscosity,” 

Biophys. J. 106, 1763 (2014). [CHRNS]

Yu, J., Phelan, D., Rodriguez-Rivera, J.A., Podlesnyak, A., Louca, D., 

“Magneto-Polaron Formation and Field-Induced Effects with 

Dilute Doping in LaCo1-yNiyO3,” J. Supercond. Nov. Magn. 

26(8), 2627 (2013). [CHRNS]

Yue, A.T., Dewey, M.S., Gilliam, D.M., Greene, G.L., Laptev, 

A.B., Nico, J.S., Snow, W.M., Wietfeldt, F.E., “Improved 

Determination of the Neutron Lifetime,” Phys. Rev. Lett. 

111, 222501 (2013).

Zhang, C., Li, H.-F., Song, Y., Su, Y., Tan, G., Netherton, T., 

Redding, C., Carr, S.V., Sobolev, O., Schneidewind, A., 

Faulhaber, E., Harriger, L.W., Li, S., Lu, X., Yao, D.-X., Das, T., 

Balatsky, A.V., Brückel, Th., Lynn, J.W., Dai, P., “Distinguishing 

s± and s++ Electron Pairing Symmetries by Neutron Spin 

Resonance in Superconducting NaFe0.935Co0.045As,” 

Phys. Rev. B 88(6), 064504 (2013).

Zhang, C., Harriger, L.W., Yin, Z., Lv, W., Wang, M., Tan, G., Song, 

Y., Abernathy, D.L., Tian, W., Egami, T., Haule, K., Kotliar, G., 

Dai, P., “Effect of Pnictogen Height on Spin Waves in Iron 

Pnictides,” Phys. Rev. Lett. 112(21), 217202 (2014).

Zhang, H., Khodadadi, S., Fiedler, S.L., Curtis, J.E., “Role of Water 

and Ions on the Dynamical Transition of RNA,” J. Phys. 

Chem. Lett. 4, 3325 (2013).

Zhang, R., Singh, G., Dang, A., Dai, L., Bockstaller, M.R., Akgun, 

B., Satija, S., Karim, A., “Nanoparticle-Driven Orientation 

Transition and Soft-Shear Alignment in Diblock Copolymer 

Films via Dynamic Thermal Gradient Field,” Macromol. 

Rapid Commun. 34, 1642 (2013).

Zhao, J., Shen, Y., Birgeneau, R.J., Gao, M., Lu, Z.-Y., Lee, D.-H., 

Lu, X.Z., Xiang, H.J., Abernathy, D.L., Zhao, Y., “Neutron 

Scattering Measurements of Spatially Anisotropic Magnetic 

Exchange Interactions in Semiconducting K0.85Fe1.54Se2

(TN = 280 K),” Phys. Rev. Lett. 112(17), 177002 (2014).

Zhou, S., Zhang, J., Liu, D., Hu, Q., Huang, Q., “The Effect of 

Samarium Doping on Structure and Enhanced Thermionic 

Emission Properties of Lanthanum Hexaboride Fabricated by 

Spark Plasma Sintering,” Phys. Status Solidi A 211(3), 555 

(2014).

Zhou, Z., Hollingsworth, J.V., Hong, S., Wei, G., Shi, Y., Lu, X., 

Cheng, H., Han. C.C., “Effects of Particle Softness on Shear 

Thickening of Microgel Suspensions,” Soft Matter, in press. 

[CHRNS]

Zhu, Z.-H., Nicolaou, A., Levy, G., Butch, N.P., Syers, P., Wang, X.F., 

Paglione, J., Sawatzky, G.A., Elfimov, I.S., Damascelli, A., 

“Polarity-Driven Surface Metallicity in SmB6,” Phys. Rev. Lett. 

111(21), 216402 (2013).

Zorko, A., Adamopoulos, O., Komelj, M., Arc ̆on, D., Lappas, A., 

“Frustration-Induced Nanometre-Scale Inhomogeneity in a 

Triangular Antiferromagnet,” Nat. Commun. 5, 3222 (2014).

2014 ACCOMPLISHMENTS AND OPPORTUNITIES 81PUBLICATIONS
Instruments and Contacts

(name, tel. 301-975-xxxx, email)

High resolution powder diffractometer (BT-1):

• J. K. Stalick, 6223, judith.stalick@nist.gov

• H. Wu, 2387, hui.wu@nist.gov

• Q. Z. Huang, 6164, qing.huang@nist.gov

• C. M. Brown, 5134, craig.brown@nist.gov

Residual stress diffractometer (BT-8):

• T. Gnaeupel-Herold, 5380, thomas.gnaeupel-herold@nist.gov

30-m SANS instrument (NG-7): 

• Y. Liu, 6235, yun.liu@nist.gov

• P. D. Butler, 2028, paul.butler@nist.gov

• J. R. Krzywon, 6650, jkrzywon@nist.gov

30-m SANS instrument (NG-B 30m) (CHRNS):

• B. Hammouda, 3961, hammouda@nist.gov

• S. Krueger, 6734, susan.krueger@nist.gov

• C. Gagnon, 2020, cedric.gagnon@nist.gov

10-m SANS instrument (NG-B) (nSoft): 

• R. Jones, 4624, ronald.jones@nist.gov

• K. Weigandt, 8396, kathleen.weigandt@nist.gov

USANS, Perfect Crystal SANS (BT-5) (CHRNS):

• D. F. R. Mildner, 6366, david.mildner@nist.gov

• P. D. Butler, 2028, paul.butler@nist.gov

Polarized Beam Reflectometer/Diffractometer (NG-D):

• B. J. Kirby, 8395, brian.kirby@nist.gov

• J. A. Borchers, 6597, julie.borchers@nist.gov

• C. F. Majkrzak, 5251, cmajkrzak@nist.gov

MAGIK, Off-Specular Reflectometer (NG-D):

• B. B. Maranville, 6034, brian.maranville@nist.gov

• J. A. Dura, 6251, joseph.dura@nist.gov

Neutron reflectometer-horizontal sample (NG-7): 

• S. K. Satija, 5250, satija@nist.gov

Double-focusing triple-axis Spectrometer (BT-7): 

• Y. Zhao, 2164, yang.zhao@nist.gov

• D. Parshall, 8097, daniel.parshall@nist.gov

• J. W. Lynn, 6246, jeff.lynn@nist.gov

SPINS, Spin-polarized triple-axis spectrometer (NG-5): 

• L. Harriger, 8360, leland.harriger@nist.gov

Triple-axis spectrometer (BT-4):

• W. Ratcliff, 4316, william.ratcliff@nist.gov

FANS, Filter-analyzer neutron spectrometer (BT-4): 

• T. J. Udovic, 6241, udovic@nist.gov

DCS, Disk-chopper time-of-flight spectrometer (NG-4) (CHRNS):

• J. R. D. Copley, 5133, jcopley@nist.gov

• N. Butch, 4863, nicholas.butch@nist.gov

• C. M. Brown, 5134, craig.brown@nist.gov

HFBS, High-flux backscattering spectrometer (NG-2) (CHRNS):

• M. Tyagi, 2046, madhusudan.tyagi@nist.gov

• W. Zhou, 8169, wei.zhou@nist.gov

NSE, Neutron spin echo spectrometer (NG-5) (CHRNS): 

• A. Faraone, 5254, antonio.faraone@nist.gov

• M. Nagao, 5505, michihiro.nagao@nist.gov

MACS, Multi-angle crystal spectrometer (BT-9) (CHRNS): 

• J. A. Rodriguez-Rivera, 6019, jose.rodriguez@nist.gov

• Y. Qiu, 3274, yiming.qiu@nist.gov

Cold-neutron prompt-gamma neutron activation analysis (NG-D): 

• R. L. Paul, 6287, rpaul@nist.gov

• D. J. O’Kelly, 8793, donna.okelly@nist.gov

Thermal-neutron prompt-gamma activation analysis (VT-5): 

• R. G. Downing, 3782, gregory.downing@nist.gov

Other activation analysis facilities: 

• D. J. O’Kelly, 8793, donna.okelly@nist.gov

Cold neutron depth profiling (NG-1):

• R. G. Downing, 3782, gregory.downing@nist.gov

Neutron Imaging Station (BT-2):

• D. Jacobson, 6207, david.jacobson@nist.gov

• D. Hussey, 6465, daniel.hussey@nist.gov

• M. Arif, 6303, muhammad.arif@nist.gov

Neutron interferometer (NG-7):

• M. Arif, 6303, muhammad.arif@nist.gov

• D. Jacobson, 6207, david.jacobson@nist.gov

• D. Hussey, 6465, daniel.hussey@nist.gov

Fundamental neutron physics station (NG-C): 

• J. Nico, 4663, nico@nist.gov

Fundamental neutron physics station (NG-6):

• NG-6M: M. S. Dewey, 4843, mdewey@nist.gov

• NG-6U: H. P. Mumm, 8355, pieter.mumm@nist.gov

• NG-6: J. Nico, 4663, nico@nist.gov

Theory and modeling:

• J. E. Curtis, 3959, joseph.curtis@nist.gov

• T. Yildirim, 6228, taner@nist.gov

Instruments under development:

vSANS instrument:

• J. G. Barker, 6732, john.barker@nist.gov

• C. J. Glinka, 6242, charles.glinka@nist.gov

CANDOR, White-beam reflectometer/diffractometer:

• F. Heinrich, 4507, frank.heinrich@nist.gov

• C. F. Majkrzak, 5251, charles.majkrzak@nist.gov

82 NIST CENTER FOR NEUTRON RESEARCH I N S T R U M E N T S A N D C O N T A C T S 
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:

Steve Kline

301-975-6243

steven.kline@nist.gov

For general information on the facility:

Rob Dimeo

301-975-6210

robert.dimeo@nist.gov

Dan Neumann

301-975-5252

dan.neumann@nist.gov

For information on visiting the 

facility and/or user access questions:

Julie Keyser

301-975-8200

julie.keyser@nist.gov 

Mary Ann FitzGerald

301-975-8200

maryann.fitzgerald@nist.gov

For information on performing 

research at the facility:

Bill Kamitakahara

301-975-6878

william.kamitakahara@nist.gov

Facility address:

NIST Center for Neutron Research

National Institute of Standards and Technology

100 Bureau Drive, Mail Stop 6100

Gaithersburg, MD 20899-6100 USA

2014 ACCOMPLISHMENTS AND OPPORTUNITIES

N I S T C E N T E R F O R N E U T R O N R E S E A R C H C O N T A C T S 
NIST CENTER FOR NEUTRON RESEARCH

National Institute of Standards and Technology

100 Bureau Drive, MS 6100

Gaithersburg, MD 20899-6100

www.ncnr.nist.gov