NIST SP 1006

October 2003

NCNR 2003

NIST Center for Neutron Research

Accomplishments and Opportunities
On the cover: An up-to-date view of instruments in the NCNR cold neutron guide hall.

Cover photography by Robert Rathe
NCNR 2003

NIST Center for

Neutron Research

Accomplishments

and Opportunities

NIST Special Publication 1006

J. Michael Rowe, Director

Ronald L. Cappelletti, Editor

October 2003

U.S. DEPARTMENT OF COMMERCE

Donald L. Evans, Secretary

Technology Administration

Phillip J. Bond, Under Secretary of Commerce for Technology

National Institute of Standards and Technology

Arden L. Bement, Jr., Director
DISCLAIMER

Certain commercial entities, equipment, or materials may be identified in

this document in order to describe an experimental procedure or concept

adequately. Such identification is not intended to imply recommendation or

endorsement by the National Institute of Standards and Technology, nor is it

intended to imply that the entities, materials, or equipment are necessarily

the best available for the purpose.

National Institute of Standards and Technology Special Publication 1006

Natl. Inst. Stand. Technol. Spec. Publ. 1006, 72 pages (October 2003)

CODEN: NSPUE2

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For sale by the Superintendent of Documents, U.S. Government Printing Office

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Mail: Stop SSOP, Washington, DC 20402-0001

ii
Contents

iii

NCNR Founders Honored at NIST ....................................................................................................................................... iv

Foreword................................................................................................................................................................................ vi

NCNR Milestones ................................................................................................................................................................. viii

The NIST Center for Neutron Research (NCNR) .................................................................................................................. 1

NIST Center for Neutron Research Layout ........................................................................................................................... 2

NCNR Images 2003 ................................................................................................................................................................. 4

Research Highlights

Instrumentation Development and Applications

The Advanced Neutron Diffractometer / Reflectometer (AND/R) ............................................................................................. 6

A New Neutron Imaging Facility at BT-6 for the Non-Destructive Analysis of Working Fuel Cells ........................................... 8

Measurement of Deuterium Scattering Length ....................................................................................................................... 10

Demonstration of the Metrological Basis of Instrumental Neutron Activation Analysis ............................................................ 12

Chemical Physics and Biology

Structural and Vibrational Characterization of Tetracene as a Function of Pressure ................................................................ 14

Fast Dynamics in Stabilization of Proteins ........................................................................................................................... 16

Bio-Membrane Flexibility Studied in the Presence of Cholesterol and Salt .......................................................................... 18

Dynamics of Glucose Solutions ......................................................................................................................................... 20

ATP-Induced Shape Change in a Model Protein Complexed in Chaperonins ...................................................................... 22

Phase Sensitive Neutron Reflectometry on a Water-Cushioned Biomembrane-Mimic ......................................................... 24

Soft Condensed Matter

Biomaterials Constructed Via Designed Molecular Self-Assembly ...................................................................................... 26

Scattering Studies of the Structure of Colloid-Polymer Suspensions and Gels ..................................................................... 28

Condensed Matter and Applied Physics

Spinons, Solitons, and Breathers in Spin-1/2 Chains .......................................................................................................... 30

Structure and Properties of the Integer Spin Frustrated Antiferromagnet GeNi2O4 ................................................................. 32

Residual Stresses and Optimizing Machining Strategies for Aluminum Bars ........................................................................ 34

Multicriticality in the Bragg-Glass Transition ........................................................................................................................ 36

Hidden Symmetries and Their Consequences in the t2g Cubic Perovskites ........................................................................ 38

Structural Characterization of Acrylonitrile Catalysts ............................................................................................................ 40

Serving the Science and Technology Community ........................................................................................................... 42

The User Program ............................................................................................................................................................. 42

A New Voice for Users ...................................................................................................................................................... 42

Center for High Resolution Neutron Scattering .................................................................................................................... 43

Cold Neutrons for Biology and Technology ......................................................................................................................... 43

NOBUGS 2002 ................................................................................................................................................................ 43

Ninth Annual Summer School ............................................................................................................................................ 43

Theory, Modeling, and Neutron Scattering .......................................................................................................................... 44

Independent Programs .................................................................................................................................................... 44

Operations .................................................................................................................................................................... 47

Facility Developments ............................................................................................................................................. 48

Data Analysis, Visualization, and Modeling Software Developments .................................................................. 48

Data Acquisition and Instrument Control ....................................................................................................... 49

Sample Environment Equipment ............................................................................................................ 50

BT-7 Double Focusing Triple Axis Spectrometer Development ......................................................... 50

Publications ............................................................................................................................... 51

Instruments and Contacts ................................................................................................. 64

Contacts ............................................................................................ Inside Back Cover
NIST Director Arden Bement (second from

left) joins Mike Rowe (left) and Jack Rush

(center) in congratulating Harry Landon

and Carl Muehlhause

Harry Landon with Jack Rush and

Fred Shorten

The honorees being congratulated by

Mike Rowe at the presentation ceremony

Robert S. Carter Carl O. Muehlhause Harry Landon

Portraits placed in the NIST Gallery of Distinguished Scientists, Engineers and Administrators

Robert S. Carter, Carl O. Muehlhause and Harry Landon honored at

NIST Standards Alumni Association 2003 Portrait Ceremony

iv

Photography by Barry Gardner

Photography by Barry Gardner

Photography by Barry Gardner
NCNR Founders Honored at NIST

December 7, 1967,

criticality at the

NBSR, left to right:

NBS Director Allen

Astin, Harry Landon,

Carl Muehlhause,

Robert Carter, and

Associate Director

Irl Schoonover

Left to right: Mike Rowe, Pat Gallagher, Carl

Muehlhause, Tawfik Raby, Jack Rush, Bob Carter,

Sheila Landon, John Cleary, Toni Carter, and Harry

Landon tour the cold neutron guide hall of the NIST

Center for Neutron Research

Muehlhause, Landon and Carter are

presented with certificates by Mike Rowe

Sheila Landon and Mike Rowe share

a moment at the reception

These distinguished alumni designed and oversaw the building

of the NBSR and the starting of its science programs

v

Photography by Barry GardnerPhotography by Barry Gardner
Foreword

vi

This is the 15th report of the

 activities of the NIST Center for

Neutron Research (NCNR) for which I have

written an introduction, following the retirement

of Dr. Robert S. Carter (who wrote all of the

preceding introductions). It is particularly appropriate

to note this milestone this year for two reasons. First,

because Bob Carter, Carl Muehlhause, and Harry Landon,

the designers of the NIST reactor, are being recognized

this year by having their pictures hung in the NIST Portrait

Gallery for their contributions to NBS/NIST. This is an

honor well deserved, and we are hoping that they will all

return in September for the ceremony. Second, this will be

my last such introduction, as I intend to retire as Director

before the next one is written. Therefore, I will not limit

my remarks to this year’s accomplishments only, but try to

summarize my thoughts after 15 years as Director, and

31 years at NIST.

The source designed and guided through its formative years by Carter, Muehlhause, and Landon has been a

tremendous success, providing remarkably cost-effective

service to NIST and the nation. Its design has proved its

worth over and over, as the focus of the program has

shifted over the years from being primarily for local

nuclear physics, irradiations for analytical chemistry, and

neutron diffraction to in-house and collaborative thermal

neutron scattering involving a broader community, to its

present role as the major national center for thermal and

cold neutron research, with a full suite of scattering

instruments, an active analytical chemistry effort serving

national as well as local needs, and a thriving program in

neutron physics. With this continuing growth, expansion

and transformation in our research and measurement

activities, the need for predictable, dependable operation

has increased greatly. It is a tribute to all of the people

involved that the challenge has been met with only a

moderate increase in cost and staff, in spite of increasing

regulatory requirements, and an increase in power from 10

to 20 MW in 1985. For many years, as Chief of Reactor

Operations and Engineering, Tawfik Raby set the highest

standards for safe, reliable, and economical reactor

operations, and his successor, Seymour Weiss, has continued in this tradition. Many of our most senior operators

have retired or will in the next few years, but we have

managed to hire outstanding young people to carry on. By

the end of this year, we will apply for a license renewal for

an additional 20 years of operation, and I am confident that

it will be approved, and that the reactor will continue to

serve NIST and the nation for the foreseeable future.

While the reactor has provided the constant source of

neutrons required for success, the instrumentation around

it has been continually improved and updated. When I first

arrived at NIST in 1973, I worked with Jack Rush, Sam

Trevino and Hank Prask to develop our first triple axis

spectrometer (an instrument that has been modified and

updated regularly, and for which the last “original” part

should disappear in the next two years). (Incidentally, it

was during the design of this instrument, which was done

in part at Ames Laboratory, that I first met my wife Nancy

Chesser, who was then a staff member at Ames.) This

year alone, we have begun the installation of a nextgeneration doubly focusing thermal neutron triple axis

spectrometer which will have unprecedented intensities and

flexibility; installed a new cold neutron reflectometer/

diffractometer as part of Cold Neutrons for Biology and

Technology initiative; and commissioned a new facility for

radiography that has been used to study operating fuel

cells. We are also well into the detailed design of a new

cold neutron double-focusing triple axis spectrometer,

MACS, in partnership with The Johns Hopkins University.

We are now on our third cold neutron source, which

incorporates the experiences from the first D2O ice source

installed in 1985 and the first liquid hydrogen source. This

source operates totally reliably, and achieved a 100 %

availability (ready to run when the reactor is) this year.

The pace of instrumentation development has accelerated

continuously during my time here, to encompass ideas that

we never considered even 15 years ago. For this I am
grateful to the many people who have worked so hard over

the years — far too many to acknowledge here, but I

would be remiss if I did not mention Ivan Schroder and his

engineering colleagues, who have solved so many “impossible” engineering problems, and Bob Williams and more

recently, George Baltic, and their technical team, who put

into practice on the floor what we dreamt up in our

offices. And Pat Gallagher has led the transition from the

somewhat anarchic Cold Neutron Project to the Research

Facility Operations Group, a fully functioning group that

serves the user mission of the NCNR extraordinarily well.

Last, but far from least, the science group has grown

from the 9 regular staff members that it had when I arrived

to over 30 NIST employees and 36 long-term guest

researchers. At the same time, the mission and focus of

the group has evolved, with added responsibilities for

instrument development, support for user operations, new

research areas in soft matter, and many new interactions

with the rest of NIST and with 200 outside organizations.

Throughout my 31 years, Jack Rush, my good friend and

colleague, has guided the fortunes of the research group

with a sure and steady hand, ever alert to new opportunities, to good science, and to good people. As I have read

through this year’s science reports, and through earlier

years, I have been struck by the continuing high quality of

the research, even as the scientific emphasis has changed,

the techniques have developed, and our mode of operation

has been totally transformed. One of the greatest pleasures

of this job has been the opportunity to walk through the

facility to meet and learn from the intelligent and dedicated

people who do the research. Young and not so young,

they give me a high level of optimism for the future

because of their infectious enjoyment of their activities (it

seems wrong to call something so enjoyable work!). As

always, the science highlights that form the bulk of this

report are the final indicator of what we have done in the past

year. I hope that you enjoy reading them as much as I did.

So, in closing, I thank everyone who has been part of

my life here — I hope that what we have accomplished

together over the years is a source of pride to you, as it is

to me. I look forward to seeing the continual progress of

the NCNR, for which the best is yet to come.

vii
viii

NCNR Milestones

Groundbreaking for the cold neutron guide hall, Nov.

1987. L to R: MSEL Director Lyle Schwartz; DOC Dep.

Secy. Clarence (Bud) Brown; Rep. Connie Morella, R-Md;

NIST Dir., Ernest Ambler; and NCNR Dir., Mike Rowe.

NCNR Guide hall building

recently completed (above),

January 1989, and at

present (right).

Drilling through 20’ concrete wall to bring neutron

guides from the source, 1989.

John McTague, then of Ford Motor Co., delivered a lecture

in a series honoring NCNR founder Robert S. Carter

(seated behind), May 1992.

Mike and Nobel laureate Clifford Shull share a lighter

moment during Shull’s visit to the NCNR, 1995.

NCNR facility tour by members and staff of the U.S.

House Science Committee, May 2001. Clockwise from

the poster on the right, the members are Rep. Vernon

Ehlers (R-MI), Rep. Connie Morella (former R-MD), Rep.

Gilbert Gutknecht (R-MN) just above and behind Rep.

Morella, and Rep. Mark Udall (D-CO) just above and to

the right of Rep. Morella. Former NIST Dir. Karen Brown

is at bottom left of center. Mike is at far right.
1

The NIST Center for

Neutron Research (NCNR)

Instruments in the cold neutron guide hall.

Neutrons are powerful probes of the structure and

dynamics of materials ranging from molecules inserted

into membranes mimicking cell walls to protons migrating

through fuel cells. The unique properties of neutrons (shown

in box) can be exploited by a variety of measurement techniques to provide information not available by

other means. They are particularly well suited

to investigate all forms of magnetic materials

such as those used in computer memory storage and retrieval. Atomic motion, especially

that of hydrogen, can be measured and monitored, like that of water during the setting of

cement. Residual stresses such as those inside stamped steel automobile parts can be

mapped. Neutron-based research covers a

broad spectrum of disciplines, including engineering, biology, materials science, polymers, chemistry, and physics.

The NCNR’s neutron source provides

the intense beams of neutrons required for

these types of measurements. In addition to

the thermal energy neutron beams from the

heavy water or graphite moderators, the

NCNR has a large area liquid hydrogen moderator, or cold source, that provides intense

neutron beams for the only cold neutron facility presently operating in the United States.

 There are currently 29 experiment stations: six provide high neutron flux positions for irradiation, and 23 are

beam facilities most of which are used for neutron scattering

research. The following pages show a schematic layout of

the beam facilities. More complete descriptions of instruments can be found at www.ncnr.nist.gov.

The NCNR supports important NIST research 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, over 1700 research participants from all areas of the country, from industry, academia,

and government use the facility for measurements. 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 peer-reviewed, web-based proposal system with beam time

allocated by a Program Advisory Committee twice a year.

For details see www.ncnr.nist.gov/beamtime.html. The National Science Foundation and NIST co-fund the Center for

High Resolution Neutron Scattering (CHRNS) that operates

six of the world’s most advanced instruments. 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 at the NCNR reveal properties not available to other probes. They can behave like

microscopic magnets, can diffract like waves, or set particles into motion as they recoil from them.

Wavelengths – range from 0.1 Å to 100 Å, allowing them to form observable ripple patterns from

structures as small as atoms to as large as proteins.

Energies – of millielectronvolts, the same as that of motions of atoms in solids or liquids, waves in

magnetic materials, or vibrations in molecules. Exchanges of energy between neutrons and matter as

small as nanoelectronvolts and as large as tenths of electronvolts can be detected.

Selectivity – in scattering power varies from nucleus to nucleus almost randomly. Specific isotopes

can stand out from other isotopes, even 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.

Magnetism – makes the neutron sensitive to the magnetic spins of both nuclei and electrons, allowing

the behavior of ordinary and exotic magnets to be detailed precisely.

Neutrality – of the uncharged neutrons allows them to penetrate deeply without destroying samples,

and pass through walls controlling a sample’s environment allowing measurements under extreme

conditions. Properties ranging from the residual stresses in steel girders to the unfolding motions of

proteins are amenable to measurement by neutrons.

Capture – characteristic radiation emanating from specific nuclei capturing incident neutrons can be

used to identify and quantify minute amounts of material in pollutants or ancient pottery shards. Photography by Lynn A. Shuman
2

23 24

8

9

10

11

12

4 5

6

2

1

1 A Cold Neutron Depth

Profiling instrument (not shown)

for quantitative profiling of

subsurface impurities currently at

this site will be moved to another

position. Shown is MACS, a cold

neutron Triple Axis Crystal

Spectrometer under construction

with double focusing monochromator and multiple crystal

analyzer/detectors that can be

flexibly configured for several

energies simultaneously or for

high throughput at one energy.

2 BT-6 (temporary location)

Neutron Imaging Facility for

imaging hydrogenous matter in

large components such as water

in fuel cells or lubricants in

engines.

3 BT-7 Triple Axis Crystal

Spectrometer with fixed incident

energy for measurements of

excitations and structure.

4 BT-8 Residual Stress

Diffractometer optimized for

depth profiling of residual stress in

large components.

5 BT-9 Triple Axis Crystal

Spectrometer for measurements

of excitations and structure.

6 Thermal Column a very wellthermalized beam of neutrons

used for radiography, tomography,

dosimetry and other experiments.

7 BT-1 Powder Diffractometer

with 32 detectors; incident wavelengths of 0.208 nm, 0.154 nm,

and 0.159 nm, with highest

resolution of δd/d = 8 x 10-4.

8 BT-2 Triple Axis Crystal

Spectrometer with polarized

beam capability for measurement

of magnetic dynamics and

structure.

9 BT-4 Filter Analyzer Neutron

Spectrometer with cooled Be/

Graphite filter analyzer for

chemical spectroscopy.

10 BT-5 Perfect Crystal

Diffractometer SANS small

angle neutron scattering instrument

for microstructure on the 104 nm

length scale, sponsored by the

National Science Foundation and

NIST, part of the Center for High

Resolution Neutron Scattering

(CHRNS).

11 NG-7 Horizontal Sample

Reflectometer allows reflectivity

measurements of free surfaces,

liquid vapor interfaces, as well as

polymer coatings.

12 Neutron Interferometry and

Optics Station with perfect

silicon interferometer; vibration

isolation system provides

exceptional phase stability and

fringe visibility.

13 Spin Polarized Triple Axis

Spectrometer (SPINS) using

cold neutrons with position

sensitive detector capability for

high-resolution studies — part of

CHRNS.

7 13

3
3

NIST Center for Neutron Research Layout

18

16

17

19

20

21

22

14

15

14 Spin Echo Spectrometer

offering neV energy resolution,

based upon Jülich design,

sponsored by NIST, Jülich and

ExxonMobil — part of CHRNS.

15 Prompt Gamma Activation

Analysis cold neutron fluxes

allow detection limit for H of 1 μg

to 10 μg. Focused beams are

available for profiling.

16 NG-7 30 m SANS for microstructure measurements sponsored by

NIST, ExxonMobil, and the

University of Minnesota.

17 Neutron Physics Station

offering three cold neutron beams

having wavelengths of 0.5 nm,

0.9 nm, and “white” that are

available for fundamental neutron

physics experiments.

18 Fermi Chopper hybrid time-offlight (TOF) Spectrometer for

inelastic scattering with selected

incident wavelengths between

0.23 nm and 0.61 nm.

19 Disk Chopper TOF Spectrometer a versatile time-of-flight

spectrometer, with beam pulsing

and monochromatization effected

by 7 disk choppers. Used for

studies of dynamics in condensed

matter, including macromolecular

systems — part of CHRNS.

20 NG-3 30 m SANS for microstructure measurements sponsored by

the National Science Foundation

and NIST — part of CHRNS.

21 Backscattering Spectrometer

high intensity inelastic scattering

instrument with energy resolution

< 1 μeV, for studies of motion in

molecular and biological systems

— part of CHRNS.

22 NG-1 10 m SANS (under

construction.) It replaces the

current 8 m SANS and will be

made available for CHRNS use

along with use by the NIST

Polymers Division.

23 Vertical Sample Reflectometer

instrument with polarization

analysis capability for measuring

reflectivities down to 10-8 to

determine subsurface structure.

24 Advanced Neutron

Diffractometer / Reflectometer

(AND/R), a vertical sample

reflectometer with polarization

analysis and off-specular reflection

capabilities for measuring

reflectivities down to 10-8. It is part

of the Cold Neutrons for Biology

and Technology program

committed to studies of biological

membrane systems.
4

Theory, Modeling and Neutron Scattering Workshop attendees, August 2003

NCNR’s Inma Peral (back to camera) and

Yiming Qiu (second from right) with students

Watching and analyzing data at DCS

NCNR’s Inma Peral prepares a

cryostat at DCS

The flame produces in situ soot for

a SANS study by WPI’s Barb

Wyslouzil and U Del.’s Hai Wang

NCNR’s John Copley points out

salient features of DCS to

summer school students

Photography by Lynn A. Shuman
5

NCNR Images 2003

NCNR’s Richard Azuah extols the virtues of

Backscattering to summer school fans

U. Bristol’s Terry Cosgrove and

collaborators take a pointer from

NCNR’s Lionel Porcar

U Del.’s Eric Kaler discusses a SANS

pattern with his group

SURF student Andrew Rockwell at

the NG-1 reflectometer controls with

NCNR’s Chuck Majkrzak

Oberlin’s Steven FitzGerald

supervises his undergraduate

collaborators loading a sample

Look up and smile! NCNR’s Seung-Hun Lee

and Peter Gehring (rear) with summer school

students at the SPINS analyzer

Photography by Lynn A. Shuman

Photography by Lynn A. Shuman Photography by Lynn A. Shuman
6

The recently installed (July 2003)

 Advanced Neutron Diffractometer/

Reflectometer (AND/R) adds new capabilities

for bio-membrane research and diffuse scattering

measurement to the NCNR. It aims to provide a

focal point for structural biology research, combining

an increased in-house staff to serve and interact with

an expanded user program. Furthermore, it will benefit

the NCNR reflectometry program by increasing available

beam time overall. Of the AND/R beamtime, 75 % will be

available to the CNBT partners and 25 % to general users

through the NCNR proposal system. With the AND/R

located just upstream of NG-1 reflectometer, this pair of

instruments will share common facilities, equipment, and

expertise.

The AND/R is the centerpiece of the Cold Neutrons

for Biology and Technology (CNBT) program, which is

committed to the development of advanced neutron

scattering instruments for studies of membrane systems.

CNBT was funded by the National Institutes of Health

(NIH), National Center for Research Resources on 30 September 2001 with additional support from NIST, the

University of California at Irvine and the University of

Pennsylvania. The CNBT partnership consists of investigators from six universities: UC Irvine (principal investigator

The Advanced Neutron

Diffractometer/Reflectometer (AND/R)

Stephen H. White), Johns Hopkins University, Penn, Rice,

Duke, Carnegie Mellon and investigators from NIST.

Additional collaborators are from UC San Diego, Los

Alamos National Laboratory, and the NIH. The facilities

consist of the AND/R, a 30 m small-angle neutron spectrometer (SANS) dedicated 10 % to CNBT, a fully

equipped biology laboratory, and two state-of-the-art

computer facilities (one at U C Irvine, and one at NCNR)

for molecular dynamics computations. This combination

provides a new capability for the United States.

The AND/R is modeled after the highly successful

polarized beam reflectometer on the NG-1 neutron guide.

Like the NG-1 reflectometer, the AND/R will have a

horizontal scattering plane, which provides unrestricted

access to higher scattering angles. Other features common

to both instruments are the polarized beam capability to

enable the use of magnetic reference layers for phase

inversion of data, and a vertically focusing monochromator

to increase the flux on the sample.

Additional features make the instrument well suited

for both reflectometry and diffraction investigations of

biological systems. First, the AND/R can operate using

either a larger 5 cm “pencil” detector (increasing the flux at

higher momentum transfer, Q) or a 2-dimensional position

sensitive detector (PSD). By simultaneously measuring

non-specular scattering from large areas in reciprocal

space, the PSD will make it much more efficient to obtain

information on in-plane structures. Also, the sample tables

will accommodate larger sample environments (up to

26 cm (10.2")) from tabletop to beam center and up to

454 kg (1000 lb) or an Eulerian cradle (for diffraction

experiments from a single crystal). Variable sample to

monochromator distance (from 206 cm (81") to 236 cm

(93")) and sample to detector distances (from 61 cm (24")

to 173 cm (68")) will allow the user to select the Q range

covered by the PSD. Optical benches, both inside and

outside the shutter, will make customization and upgrades

of the neutron optical components simpler to implement.

An increased number of motorized axes as well as additional supporting software provided by a dedicated programmer in the CNBT program will make this userfriendlier instrument. The Advanced Neutron Diffractometer Reflectometer, shown in polarized

beam mode with the “pencil” detector enclosed within the box at left.

(For clarity, some shielding is not shown.)
Instrumentation Development and Applications

7

J. A. Dura, D. J. Pierce, C. F. Majkrzak

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899

AND/R (right) and NG-1 Reflectometer floor plan. The large circles

indicate the travel of the detector arm in its fully extended position.

Blue, purple and red rectangles are the control desks, electronic racks

and beamstops respectively. The instruments will be separated by both

a fixed rail and a tensile barrier (not shown).

A number of general areas of investigation of biological membrane and biomimetic thin film structures are

currently envisioned for the AND/R instrument. These

include specular reflectometry measurements to reveal the

compositional depth profile along the surface normal (with

spatial resolution approaching a fraction of a nanometer) as

well as non-specular scattering studies of in-plane density

variations and structures. The specular reflectometry can

be performed on single bilayer membrane or multilayered

systems to determine the location of certain macromolecular entities of biological interest, such as cholesterol,

various toxins, or transmembrane proteins. Non-specular

measurements of in-plane objects typically will require

multilayered samples to obtain sufficient signal.

The NCNR cold source and guide combined with

optimized neutron optics and the capabilities described

above are expected to make measurements using AND/R

especially well suited to addressing key scientific issues on

biological membranes.

NCNR staff and CNBT visitors gather at the completed AND/R

instrument. Left to right: Michael Paulaitis, JHU; Kevin O’Donovon,

NCNR; Don Pierce, NCNR; Huey Huang, Rice; Steven White, UCI; Anne

Plant, NIST Biotech; Mathias Lösche, JHU; Jack Rush, NCNR; Tom

Macintosh, Duke; Joe Dura, NCNR; Susan Krueger, NCNR; Chuck

Majkrzak, NCNR.
8

A dramatic step toward analyzing the

 performance and the operational

characteristics of a working fuel cell has taken

place at the NCNR. A new Neutron Imaging

Facility (NIF) shown in Fig. 1 has been constructed

in a cooperative effort between the Department of

Commerce and the Department of Energy. This facility

uses neutrons to peer inside the fuel cell to view water

forming and moving throughout the cell. In a fuel cell,

water is formed as a by-product of the reaction between

hydrogen and oxygen. If the water does not drain quickly

and efficiently, then fuel cells will not work properly.

Water formation is also a signature of activity in a fuel cell,

so the lack of water formation demonstrates a defective

area of the fuel cell.

Since fuel cells are not transparent to visible light,

other forms of penetrating radiation (example: x-rays,

neutrons) must be used to analyze their operation. X-ray

imaging is not suitable because hydrogen is nearly invisible

to the high energy x-rays required to penetrate the metallic

encasement of the fuel cell. Neutrons, which are neutral

particles, can easily penetrate metals and still be extremely

sensitive to water in quantities less than a microgram. The

reason for this is best illustrated by a comparison of the

relative scattering cross-sections shown in Fig. 2. The

large x-ray cross-section of Al compares to a small neutron

A New Neutron Imaging Facility at

BT-6 for the Non-Destructive Analysis

of Working Fuel Cells

cross-section. Conversely the x-ray cross-section for

hydrogen is small compared to the neutron cross-section.

This makes neutrons ideal for sensing microgram quantities of water. An example of neutron imaging fuel cells is

shown in Fig. 3. In the image the gas distribution system

of a fuel cell shows up as the serpentine tracks. The

purpose of these channels is to

distribute gas evenly to the membrane

and to act as a drain for water coming

out. In these images the neutrons

easily penetrate the fuel cell when dry.

As the fuel cell runs, water builds up

and appears as a darker shadow

region of the images on the left.

Computer analysis allows the scattering from the dry cell to be removed,

revealing only the water formation in

both the flow channels and the gas

diffusion media, as shown in the

colorized images on the right. Large

amounts of water appear as red and

dry regions appear as black.

Although this new facility has

been constructed for the specific

purpose of imaging fuel cells, it has potentially many other

applications in industrial and applied research. Among

these are imaging of automotive parts to study metalcasting techniques, oil lubrication in an automotive engine,

and non-destructive analysis of archeological artifacts.

Fig. 1. The new thermal neutron imaging facility at the NCNR.

Fig. 2. Neutron and x-ray scattering cross-sections compared. Note that

neutrons penetrate through Al much better than x rays do, yet are

strongly scattered by hydrogen.

X-ray cross section

Neutron cross section

H D C O Al Si Fe
Instrumentation Development and Applications

9

D. Jacobson, M. Arif, and P. Huffman

Physics Laboratory Ionizing Radiation Division

National Institute of Standards and Technology

Gaithersburg, MD 20899

R. Satija

Duke University

Durham, NC 27708

Fig. 3. A fuel cell: gas distribution channels shown disassembled on top. When assembled, images of

the operating cell were taken every second for 2000 seconds. The water build-up in both the gas

diffusion media and the flow channels is most clearly visible in the colorized images in which the

underlying dry fuel cell has been computationally removed.

The very different sensitivities to

various elements of x-ray and

neutron scattering illustrated in

Fig. 2 means that the two

techniques could be considered

complimentary methods of nondestructive analysis. Because of

this broad range of applications,

this facility was optimized for

beam size, spatial resolution and

neutron flux. Currently the beam

exiting the collimator traverses

≈ 4 m and bathes the sample over

an 18 cm diameter circle with a

uniform neutron fluence rate of

108 cm-2 sec-1, making it possible

to image large objects (see

Fig. 4.)

Future detector development of this method should be

able to extend time resolution to

the 30 ms level and spatial

resolution to the 10 μm level. In

addition, the methods of codedsource imaging could allow

3-dimensional imaging of the

membrane and gas diffusion

media. These developments would be able to provide a

critical tool for fuel cell developers to analyze how small

design changes affect a real fuel cell.

Fig. 4. Beam size at the sample position. The large diameter beam

having a uniform fluence rate is important for imaging industrial scale

objects.

Picture of flow channels in the fuel cell stack

Lowest water 

concentration

Highest water 

concentration

t = 1000 s

t = 0 s

t = 2000 s

Neutron images of

fuel cell stack

Water images

dry fuel cell removed

Neutron Beam Size

Fluence

rate = 108 neutrons

cm2 sec

increasing neutron intensity

180.4 mm

203.6 mm
10

Fig. 1. A picture of the setup is shown on the right and a schematic plan view is shown on the left.

H-beam detector

gas cell

phase shifter

Neutron beam

Interferometer

O-beam detector

cell out

Temp B

vacuum

cell phase

shifter

1 cm

n-beam

Si (111)

quartz

alignment

flag

3He

detectors

cell

in

gas

cell

H beam

O beam

Temp A

A recent high precision measurement

 of the scattering length, b, of

deuterium gas has been performed using

neutron interferometry at the NIST Neutron

Interferometer and Optics Facility [1, 2]. Accurate

measurement of the scattering length is important to

the fundamental nature of how a neutron scatters from

an atom. This scattering length depends on the nature of

the nuclear potential, and, therefore, the prediction of this

value is an important test for models of the nuclear

potential. Currently only few nucleon systems can be

accurately modeled, and measurements of scattering

lengths of light nuclei are considered to be the most

interesting. To date the most accurate methods to measure

the scattering length have been neutron optical methods,

and prior to this work the most accurate determination of

the scattering length of deuterium has been that of gravity

reflectometry. These neutron optical methods measure the

bound coherent scattering length, b, by accurately determining the index of refraction, n, given by,

(1)

In Eq. (1), m is the elemental species (important

when correcting for contaminants); b is the local mean

forward coherent scattering length averaged over the two

spin dependent free scattering channels

(2)

where (for S = total spin = [1/2 or 3/2]) are the free

doublet and quartet scattering lengths; mn is the neutron

mass and md is the deuteron atomic

mass; λ is the neutron deBroglie

wavelength; σ is the total cross

section made up of the scattering and

absorption cross sections; nr

 is the

real part of the index of refraction;

and N is the atom density of the

material. For all elements the real part

of n is nearly unity: the magnitude of

(nr - 1) for typical neutron-nucleus

potentials is approximately 1 × 10-5.

The imaginary part of Eq. (1) accounts for the attenuation of the wave

Measurement of

Deuterium Scattering Length

amplitude due to scattering and absorption. Although such

inelastic processes do not contribute to the interference of

the amplitudes that travel on the two different paths

through the interferometer since they make the path

distinguishable in principle, they appear in the expression

for the forward scattering amplitude as a result of the

optical theorem. The interferometer efficiently filters out

such inelastic processes that occur in the sample and in the

Si interferometer blades.

Neutron interferometry is mainly sensitive to the

real part of the refractive index by measuring the phase

shift of a sample placed on one of two indistinguishable

paths in the silicon neutron interferometer [3]. This phase

shift can be written as

(3)

where Deff stands for the effective thickness of the medium

along the direction of wave propagation. This phase shift

can be very large; thus the neutron interferometric method

is very sensitive to the index of refraction. Here we

present the results of a measurement of the phase shift of a

1 cm thick sample of D2 gas. The experimental setup for

this measurement is shown in Fig. 1. The phase shift data

converted to scattering length by inverting Eq. (3) are

shown plotted in Fig. 2. Finally, averaging all values in

Fig. 2 and combining the statistical and systematic uncertainties, we obtain the value for the scattering length

bnd = (6.665 ± 0.004) fm, which is plotted relative to

previous measurements of the scattering length in Fig. 3.

The new world average is then bnd = (6.669 ± 0.003) fm,

.

nd

2S+1

a

nd

4

nd

2

d

n d 1 3 2 3

m

m m b ++ = ( ( a a ( (



 



1 – 2 2 4 2 2 2 = r + i ≈ Σ – +

m

m m m m m n n in (N π ( b (σ ( iN σ ( π (

∆ = – = mnr kDeff N m b m Deff φ ( 1 ( –Σ λ
Instrumentation Development and Applications

11

6.75

6.70

6.65

6.60

b (fm)

+F

-F

0 2 4 6 8 10 12 14

Time (days)

statistical uncertainty of mean

systematic uncertainty

Fig. 2. All of the phase shift measurements made are shown here. The

estimated statistical uncertainty per point agrees well with the statistical

scatter of the data. The sizes of the final statistical and systematic

uncertainties are also shown here for comparison purposes.

Fig. 3. Shown here are all the values and names of methods used to

measure b for deuterium over the years. The average is a weighted

average including all of these measurements.

Fig. 4. The 1σ (blue) and 2σ (red) confidence intervals are shown here.

Only two theories fall within 2σ of this result.

P. R. Huffman, D. L. Jacobson and M. Arif

Physics Laboratory Ionizing Radiation Division

National Institute of Standards and Technology, Gaithersburg, MD 20899-8461

S. A. Werner

Physics Laboratory Ionizing Radiation Division

National Institute of Standards and Technology, Gaithersburg, MD 20899-8461

 and

University of Missouri-Columbia, Columbia, MO 65211

K. Schoen and H. Kaiser

University of Missouri-Columbia, Columbia, MO 65211

T. C. Black

University of North Carolina at Wilmington, Wilmington, NC 28403-3297

W. M. Snow

Indiana University/IUCF, Bloomington, IN 47408

 and

S. K. Lamoreaux

Los Alamos National Laboratory

Los Alamos, NM 87545

which is slightly lower than the previous world average of

bnd = (6.673 ± 0.0045) fm.

This measurement has improved on the uncertainty

reported by previous interferometric measurements by

more than a factor of 10, and by nearly a factor of two

over the previous results from gravity reflectometry. Such

precision measurements of the scattering length are

important for various theories dealing with 3 nucleon

forces (3NF). Looking back at Eq. (2), the quartet

scattering length, which is a long-range nuclear interaction,

can be calculated accurately from nucleon-nucleon

potentials and is insensitive to 3NF effects that are currently used to calculate the shorter range doublet scattering

length. Because the effective range function in the quartet

spin channel is a smooth function of energy, the quartet

scattering can be accurately extracted from an energy

dependent phase shift analysis, so that experimental

measurement of the bound coherent scattering length and

theoretical calculation of the quartet scattering length allow

the doublet scattering length to be extracted and compared

to calculation using 3NF models. Only one of the scattering length calculations reported previous to this result falls

within the (± 1)σ confidence band of this measurement

shown in Fig. 4.

Future experiments will be able to lower the combined systematic and statistical uncertainty by as much as

a factor of 5. This would allow one to measure higher

order effects due to molecular binding in H2 and D2. Other

elements such as 3He and 3H2 could also be measured with

lower uncertainties than those currently in the open

literature.

References

[1] T. C. Black, P. R. Huffman, D. L. Jacobson, W. M. Snow, K. Schoen,

M. Arif, H. Kaiser, S. K. Lamoreaux, and S. A. Werner

Phys. Rev. Lett. 90, 192502 (2003).

[2] K. Schoen, D. L. Jacobson, M. Arif, P. R. Huffman, T. C. Black, W.

M. Snow, S. K. Lamoreaux, H. Kaiser, and S. A. Werner

Phys. Rev. C 67, 044005 (2003).

[3] H. Rauch, S. Werner, Neutron Interferometry: Lessons in Experimental Quantum Mechanics, Oxford University Press, 2000. Theory

RSC + TM3NF

AV14 + BR3NF

AV14 + TM3NF

bnd

6.625 6.650 6.675 6.700

1950 1960 1970 1980 1990 2000

6.8

6.7

6.6

6.5

6.4

4.5

4.4

4.3

and (fm)

bnd (fm)

Many Methods

Bragg Diffraction

Christiansen filter

Transmission

Gravity reflectometry

Interferometry

Current weighted

average

Year of Measurement
12

I

nstrumental neutron activation

 analysis (INAA) held a unique

position in analytical chemistry and trace

element research during the 1960s and 1970s

and has continued to prosper with applications in

environmental sciences, biology, medicine, archaeology, criminology, geo- and cosmo-chemistry, and

industry. Its position, nevertheless, has been challenged

by increasingly sensitive and versatile elemental analysis

techniques, such as atomic absorption spectrometry,

inductively coupled plasma emission spectrometry and

mass spectrometry, which today are used widely in

applications that had been a domain for INAA. However,

INAA techniques still occupy a solid niche in analytical

chemistry because of the nuclear principle of analysis with

its unique advantages, such as the insensitivity to the

chemical form, as well as the ability to completely describe

the analytical process with mathematical equations of welldetermined parameters having known uncertainties. These

principles form the metrological basis of INAA; this

experimental work explores and demonstrates the seamless

integration of the experimental requirements with the

nuclear physics principles for highest quality in the results.

In its most common form, the comparator technique,

the INAA procedure compares, by means of gamma-ray

spectrometry, the neutron-induced activities in an unknown

sample with the activities induced in a standard with

known composition. This relationship is shown in the

equation:

where Cx is the analyte amount content in the unknown

sample, with Cz the analyte amount content in the primary

assay standard, mx and mz are the masses of sample and

primary assay standard with a dry mass correction factor

w if applicable. The decay corrected counting rates for the

indicator gamma-ray of unknown A0x and of standard A0z

are derived from the measurement. The ratios of isotopic

abundances Rθ for unknown and standard, of neutron

fluences Rφ (including fluence drop off, self shielding, and

scattering), of effective cross sections Rσ if neutron

spectrum shape differs from unknown to standard, and of

counting efficiencies Rε (differences due to geometry,

γ-ray self shielding, and counting effects), are controllable

Demonstration of the

Metrological Basis of Instrumental

Neutron Activation Analysis

experimental parameters. The highest accuracy is usually

attained when the measurement conditions are so designed

that the ratio factors R are near unity. INAA can be carried

out essentially blank free, but possible contributions from

interferences, background, or contamination are considered with the term B. The decay corrected gamma-ray

counting rate (A0) for a measured nuclide is calculated

according to A0 = N λ exp(λt1) / [1 - exp(-λ∆)] where N

is the number of counts measured in the indicator gammaray peak, with normalization to the end of irradiation

(t = 0) calculated using λ, the decay constant for the

indicator nuclide, t1, the decay time to start of count, and

∆, the elapsed time of count.

To illustrate the performance of INAA, we selected

the determination of chromium in SRM 1152a Stainless

Steel by direct non-destructive comparison with the pure

metal in the form of crystalline chromium. The experimental plan was guided by setting a goal of minimizing the

uncertainty in the analytical procedure as much as was

reasonably achievable; in the case of SRM 1152a, this

uncertainty should be comparable or smaller than the

uncertainty of the certified value. A review of the uncertainty parameters in the determination of amount content

by INAA guided the selection of sample and standards

preparation, irradiation, and counting processes to achieve

the stated goal.

Fig. 1. Plot of the flux gradients found along the axis of the irradiation

rabbits in three NBSR irradiation channels depicted by INAA of zinc

(RT-4) and nickel (RT-1, RT-5) flux monitor foils, metal amount content

based on a foil in position “0 mm” (100 %). When the rabbit is flipped

at the irradiation mid point, a nearly linear average flux distribution is

found in the center of the rabbit.

50

60

70

80

90

100

RT-4 flip

RT-1 flip

Position (mm)

RT-4

RT-1 

RT-5

Relative Amount of Metal in Monitor Foil (%)

0 10 20 30 40 50 60 70 80
Instrumentation Development and Applications

13

R. Zeisler, R. M. Lindstrom, E. A. Mackey,

and R. R. Greenberg

Analytical Chemistry Division

National Institute of Standards and Technology

Gaithersburg, MD 20899-8395

The neutron fluence distribution over the sample set

was determined as one key component in minimizing

uncertainties. For this work, flux gradients in all three

pneumatic irradiation channels of the NBSR were redetermined with metal foil flux monitors. The 0.1 mm

thick, 6 mm diameter foils of Zn or Ni were positioned in

the irradiation rabbit along the axis. The thin foils provided

an exact axial location for the estimation of the gradients;

radial gradients have been found negligible [1]. Figure 1

illustrates the range of fluence drop-off over the length of

the irradiation capsule. An INAA determination of the

metal amount in Zn or Ni foils, based on the proximal

“0 position” foil as the standard, gives directly relative flux

values. The steeper gradients towards the ends of the

rabbit may be explained by some channeling of neutrons

towards the rabbit at the proximal end, and the void of the

flight tube at the distal end. The observed linear drop-off

in RT-1 and RT-4 between 20 mm and 65 mm provides a

nearly homogeneous neutron field for samples placed in

this space when the capsule is inverted at mid-point of the

irradiation. This is shown with the data from the flipped

irradiations. Small deviations from a unity level remain in

the center space and are best assayed with flux monitors

or sample matrix elements (e.g., iron in steels) in each

irradiation set.

Other measures to minimize uncertainty included

careful control of neutron self-shielding and gamma-ray

self-absorption in samples and standards, correction for

remaining small counting geometry differences, and full

accounting of dead time and pile-up losses in the gammaray spectrometer via the virtual pulse technology [2].

Sufficiently large ( > 106) numbers of counts were

acquired for the indicator gamma rays for samples and

standards. Applying the discussed measures, an arithmetic

mean value of 17.768 % Cr was obtained from eight

determinations. This compared very well with the certified value of (17.76 ± 0.04) % Cr. The expanded uncertainty of 0.035 % Cr (0.2 % relative) met the goal of the

experimental work.

The Nuclear Methods Group is using this INAA

comparator method in highly precise and accurate measurements in the comparisons organized by the Consultative Committee for Amount of Substance (Comité

Consultatif pour la Quantité de Matière, CCQM); Table 1

summarizes the recent contributions. This work has

provided results in excellent agreement with reported

values and has shown that the principle is applicable to the

determination of all concentration levels: major elements

are determined with similar accuracy as trace elements.

The largest components of uncertainty are related to the

sample material. In case of the metal analyses, the values

of uncertainty in the fluence ratio Rφ were larger than in

the determinations of SRM 1152a, since the test materials

were in form of rather irregular metal chips. In the

determinations of the biological materials, the uncertainty in

the moisture correction w was the most significant factor

that contributed to the reported uncertainty. In all instances, the reported INAA uncertainties were comparable

to or smaller than the other techniques’ uncertainties.

The measurements are subject to some restrictions

that are dependent on the form and composition of the

samples provided. High-density materials with high

macroscopic neutron absorption cross sections require

corrections for the fluence ratio based on measurements of

uniform dimensions (thickness) of the samples and

knowledge of the complete sample composition. These

corrections call for careful experimental design and may

limit the applicability of INAA in the analysis of these

materials. The applications in light matrix (biological)

samples are governed by “unity” ratios with associated

small uncertainties. In addition, the non-destructive nature

of the INAA procedures offers a true alternative to techniques that require dissolution, a sometimes troublesome

process. Direct comparison with primary elemental

standards provides desirable traceability of the amount of

substance of an element.

References

[1] D. A. Becker, J. Radioanal. Nucl. Chem. 244, 361 (2000).

[2] G. P. Westphal, J. Radioanal. Chem. 70, 387 (1982).

Table 1. INAA results achieved in inter-laboratory comparisons

conducted under the auspices of CCQM.

CCQM

number

P-25

P-34

P-11

K-31

K-24

P-29

Matrix

Low Alloy Steel

Aluminum

Oyster Tissue

Oyster Tissue

Rice Flour

Rice Flour

Element

Cr

Mn

Mo

Cr

Mn

Fe

Cu

As

As

Cd

Z n

Unit

%

%

%

%

%

%

%

μg/g

μg/g

nmol/g

nmol/g

Value

0.4863

0.4478

0.9442

0.4097

0.3892

0.3594

0.2063

9.645

8.397

14.30

355.9

Expanded

Uncertainty

0.0031

0.0037

0.0154

0.0025

0.0038

0.0067

0.0049

0.112

0.160

0.33

8.5

Relative

Uncertainty

0.64 %

0.83 %

1.63 %

0.61 %

0.98 %

1.86 %

2.38 %

1.16 %

1.91 %

2.31 %

2.39 %

Mass Fraction
c

a

a

b

14

Fig. 1. The crystal structure of tetracene.

The multi-billion dollar electronic and

 optical device industry is always

searching for inexpensive and adaptable

materials for use in a wide variety of applications

such as display screens for communications,

entertainment and computers. Semiconducting

organic molecules are currently under intense investigation in this regard as it is possible to precisely tune their

properties through synthetic modification and to easily

control self-assembly. However, for the full promise of

organic semiconductors to be realized, a thorough understanding of the physical properties that control electronic

charge transport and photonic behavior is required.

Tetracene, an aromatic molecule consisting of

4 fused benzene rings, adopts a layered, herringbone

structure in the solid state (Fig. 1). When a layer of

tetracene is incorporated as the functional component of a

field effect transistor, the edge-on-face molecular orientation within the ab-plane of the crystal evidently provides

sufficient π-electron cloud overlap between adjacent

molecules to enable conduction of charge carriers. Conduction measurements have been performed on tetracene

as a function of pressure between ambient and 620 MPa at

room temperature [1]. The results indicate a linear

increase in conductance between ambient pressure up to

≈ 300 MPa and a sharp quenching of conduction as the

pressure is increased above 300 MPa. In order to ascertain the physical underpinnings of this observation (which

yield insight into the conduction mechanism), neutron

powder diffraction and inelastic neutron scattering measurement techniques have been employed to characterize

the pressure-dependent structural and vibrational behavior

of tetracene up to approximately 360 MPa at 298 K.

Structural and Vibrational

Characterization of Tetracene

as a Function of Pressure

The diffraction data were collected at NCNR’s High

Resolution Neutron Powder Diffractometer at BT-1 using

the Cu(311) monochromator and neutron wavelength of

1.54 Å. The six unit-cell parameters were extracted by

fitting the powder diffraction patterns using the graphical

user interface EXPGUI to the General Structure Analysis

System (GSAS) program assuming the known solid

tetracene structure [2, 3].

These unit cell parameters are shown as a function of

pressure in Fig. 2. As the pressure is increased, each side

of the unit cell contracts, resulting in a material with a

higher electron density. It is likely that the increase in

electron density accounts for the observed increase in

conduction in tetracene at pressures up to 300 MPa.

However, apparent from the unit cell angle parameters

alpha and gamma is a modification of the crystalline

structure between 210 MPa and 280 MPa. The change in

trend of the unit cell angle parameter is likely due to a

strain-induced phase transition that is believed to result in

the relative rotation of adjacent tetracene molecules within

the herringbone layer [4]. It is thought that this structural

modification is of sufficient magnitude to disrupt the

continuous π-electron cloud overlap in the low-pressure

phase of tetracene to the extent that it is no longer able to

conduct charge carriers.

In order to ascertain the role of molecular vibrations

on the conduction behavior of tetracene as a function of

pressure, inelastic neutron scattering (INS) spectra were

collected using the NCNR Filter Analyzer Spectrometer at

BT-4. The INS spectra at ambient, 218 MPa, and

359 MPa pressures are shown in Fig. 3. In addition to the

experimental data, a theoretical spectrum was constructed

from the results of an ab initio density functional theory

(for an individual molecule) employing the B3LYP functional and 6-31-G* basis set. The spectral peaks in the

experimental data at 27, 41, and 47 meV are affected

relatively strongly by the application of pressure (indicated

by their shifts to higher energy), whereas the peaks at 34

and 59 meV are moderately shifted and the peaks at 37, 56

and 68 meV display almost no shift with increasing pressure.

Trajectories defining the atomic displacement of the

tetracene molecule for each calculated vibrational mode

observed in the experimental data are schematically

depicted in Fig. 4. The vibrational modes of tetracene can
Chemical Physics and Biology

15

A. M. Pivovar and J. B. Leao

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899-8562

R. J. Chesterfield and C. D. Frisbie

University of Minnesota

Minneapolis, MN 55455-0132

be divided into two types of motions, occurring either

within or perpendicular to the ab crystal plane. Comparison of the vibrational trajectories with the peak shifts

observed in the INS data indicates that vibrational modes

occurring within the ab crystal plane are affected by the

application of pressure and those perpendicular remain

unaffected. Because the vibrational modes do not indicate

Fig. 2. The unit cell parameters of tetracene as a function of pressure at 298 K determined by fitting

the neutron powder diffraction data with EXPGUI and GSAS.

Fig. 3. Inelastic neutron scattering spectra of tetracene at 298 K at

pressure and the theoretically calculated spectrum of a tetracene

molecule.

Fig. 4. Schematic representation of the atomic trajectories of the

theoretically calculated vibrational modes of tetracene between 20 meV

and 75 meV.

atmospheric

218 MPa

359 MPa

theoretical

calculation

Intensity (relative)

Energy (meV)

20 30 40 50 60 70 80

24.44 34.23 37.94 40.24 47.87 55.64 60.22 70.93

a discrete change in behavior upon

transition to the high pressure

structural phase, it appears that the

phase transition does not affect the

dynamic behavior of the molecules

within the resolution and pressure

range of these experiments.

In summary, we have utilized

neutron scattering to investigate the

physical properties of tetracene as a

function of pressure. The conduction mechanism appears to be more

strongly dependent on the structural

arrangement of molecules within the

crystal lattice, most likely associated

with changes in π-electron cloud

overlap, than on the vibrational

behavior of the molecules. Further

studies on a series of molecules will

indicate whether this observation is

generic to all organic semiconductors or unique to tetracene.

References

[1] Z. Rang, A. Haraldsson, D. M. Kim, P. P. Ruden, M. I. Nathan, R. J.

Chesterfield, and C. D. Frisbie, Appl. Phys. Lett. 79, 2731 (2001).

[2] B. H. Toby, J. Appl. Cryst. 34, 210 (2001).

[3] A. C. Larson and R. B. von Dreele, Los Alamos National Laboratory Report LAUR 86-748 (2000).

[4] R. Jankowiak, H. Bässler, and A. Kutoglu, J. Phys. Chem. 89, 5705

(1985).

Pressure (MPa) Pressure (MPa)

Pressure (MPa) Pressure (MPa)

Pressure (MPa) Pressure (MPa)

0 100 200 300 400 0 100 200 300 400

0 100 200 300 400 0 100 200 300 400

0 100 200 300 400 0 100 200 300 400

101.5

101

100.5

100

99.5

alpha

114.5

114

113.5

113

112.5

beta

86.5

86.25

86

85.75

85.5

gamma

13.8

13.6

13.4

13.2

13

c (Å)

6.08

6.04

6

5.96

b (Å)

7.9

7.85

7.8

7.75

7.7

a (Å)
16

Fast Dynamics in

Stabilization of Proteins

Fig. 1. Debye-Waller factors from trehalose glasses with φglycerol = (+) 0,

(♦) 0.05, (▼) 0.10, (▲) 0.15, and (•) 0.20. Inset: “spring constants” of

low temperature glasses (left axis), and HRP stability lifetimes (right

axis).

Proteins can be effective agents for

 catalysis and biochemical signaling,

but to provide an appreciable shelf life, as

needed in fields like regenerative medicine or

biopharmaceuticals, one must stabilize these

inherently labile species under dry, in-vitro conditions.

Nevertheless, it is anticipated that proteinaceous

pharmaceuticals will account for half of all the new

drugs in the next 10 to 20 years [1]. It is also understood

that tissue scaffolds for regenerative medicine need to

contain stabilized signaling protein or DNA. Protein

preservation is becoming a critical technology. However,

according to Robert Langer, Chair of the FDA’s Science

Committee, improving protein stabilization technology is

now one of the greatest challenges in the fields of

biomaterials and pharmaceuticals.

Preservation can be achieved by embedding a protein

in a glassy matrix, typically a polyalcohol or sugar. Ideally

the stabilized protein is reconstituted under physiological

conditions when its function is required. Unfortunately

though, there is a loss of activity that increases as a

function of storage time. Understanding the reasons for

this loss of protein activity is a complex problem. From a

thermodynamic perspective it is important that the preservation matrix have the ability to “replace” water in terms of

the hydrogen bonding with the hydrophilic shell of the

protein. However, water replacement alone is not sufficient; not all hydrogen bonding glass-forming compounds

are effective preservation materials. In the present we

illustrate the importance of dynamics in the glassy matrix

for stabilizing proteins.

Previous studies showed that the stability of horseradish peroxidase (HRP) and yeast alcohol dehydrogenase

(YADH) could be significantly improved embedding these

proteins in glassy trehalose diluted with small amounts of

glycerol [2]. Here we use the High Flux Backscattering

Spectrometer (HFBS) and the Fermi-Chopper time-offlight Spectrometer (FCS) to illustrate that effective

preservation is achieved through a suppression of picosecond to nanosecond relaxations and/or collective atomic

vibrations. These local motions in the glass couple to the

protein and suppress the necessary precursor motions that

ultimately lead to larger scale motions that occur on the

typical physiological time and length scales.

Fig. 1 shows the hydrogen-weighted average mean

square atomic displacement <u2> for a series of lyophilized

trehalose glasses diluted with increasing amounts of

glycerol. The Q-dependence of the incoherent elastic

scattering from the HFBS spectrometer is analyzed in

terms of the Debye-Waller factor to extract <u2> from a

simple harmonic oscillator approximation, whereby

Ielastic ∝ exp(-Q2<u2>/3). As the temperature T increases

there is a decrease in Ielastic and <u2> is simply proportional

to the slope of ln(Ielastic) vs Q2 at any given T. The

0.85 μeV energy resolution of the HFBS means that only

motions faster than 200 MHz give rise to an increase of

<u2>; slower motions are seen as static.

The signatures of an effective preservation glass are

immediately evident in the T dependence of <u2> in Fig. 1.

Namely, the best protein preservation glass (φglycerol = 0.05)

yields the smallest values of <u2>. Below 250 K the nearly

linear T dependence of <u2> and the harmonic oscillator

approximate can be used to calculate an effective spring

constant (κ) for the glass. The inset shows a pronounce

peak in κ (left axis) at φglycerol = 0.05. The inset to Fig. 1

also displays the time constant for degradation of HRP

(τdeact) in room-temperature trehalose glasses as a function

of φglycerol. At φglycerol = 0.05, where the suppression of

<u2> is the greatest, the HRP stability is the greatest, more

than five times better than the undiluted trehalose. While

we do not show the data, the same effect is observed for

YADH.

60

40

20

0

[N/m]

0.00 0.10 0.20

glycerol

3.6

3.2

2.8

log( deact/h)|296 K

0.25

0.20

0.15

0.10

0.05

0.00

<u2> [ Å2 ]

0 100 200 300 400

T [ K ]

0.200.150.100.050

Tg, =
Chemical Physics and Biology

17

M. T. Cicerone and C. L. Soles

Polymers Division

National Institute of Standards and Technology

Gaithersburg, MD 20899-8541

Fig. 2. Enzyme preservation and dynamics in plasticized trehalose

glasses with φglycerol (▼) 0, (■) 0.05, and (•) 0.10. Panel (a) shows

1/<u2>, which is proportional to local dynamics (see text). Panel (b)

shows HRP activity lifetimes, and panel (c) shows YADH activity

lifetimes. Panel (d) shows apparent activation energies as a function of

glycerol content measured by HRP lifetimes (H), YADH stability (Y), and

1/<u2> (n°). Error bars represent standard uncertainties of +/- 1

standard deviation.

Fig. 3. Inelastic scattering response for trehalose at 100 K (F). See text

for explanation of crosshatched areas. Inset, estimate of boson peak to

quasielastic scattering integrated intensities.

600 x 10-6

500

400

300

200

100

0

S(Q,E

-14 -12 -10 -8 -6 -4 -2 0

E [meV]

BP/QES

0.00 0.05 0.10 0.15

7.0

7.5

8.0

8.5

9.0

d-glycerol

) [a.u.]

Parameters τdeact (room T) and κ (below 250 K) are

determined from different T regimes. To better correlate

dynamics and preservation, Fig. 2 parts (a)-(c) shows the

1/T dependencies of 1/<u2>, τdeact for HRP, and τdeact for

YADH over the same T regime. The motivation for Fig.

2(a) comes from the empirical observation that

log(viscosity) is proportional to 1/<u2> [3]. The data

trends of panels (a)-(c) are summarized in panel (d) in

terms of the apparent activation energies, Ea, defined by

the slopes of the lines. All three data sets show a maximum of Ea at φglycerol = 0.05, indicating that suppressing

the 200 GHz and faster dynamics of the glass leads to

enhanced protein stability.

We can gain further insight into the dynamics that

facilitate protein degradation by looking at the relative ratio

of the relaxations reflected in the quasielastic scattering

(QES) to the collective atomic vibrations boson peak

intensities (BP). Fig. 3 shows a typical S(Q,E) spectrum

for trehalose at 100 K obtained from a FCS measurement.

The minimum in the spectrum at –1.7 meV can be

used, in a model-independent way, to delineate the relative

strength of oscillatory and relaxational dynamics; integrating the green and blue areas provides a relative comparison

of the BP and QES intensities respectively. In the inset to

Fig. 3 there is a maximum in the relative ratio of picosecond vibrations to relaxations at φglycerol = 0.05, coincident

with the peaks in κ and protein stability. The suppression

of relaxations relative to the vibrations in the best preservation matrix is consistent with the fact that diffusive type

motions ultimately lead to protein deactivation. These

diffusive motions could be simple like the diffusion of a

reactive gas through the matrix into the protein or complex

like the irreversible unfolding of the protein.

We have shown for the first time that fast

(ω > 200 MHz) dynamics of the host glass are crucial in

stabilizing proteins. This is consistent with recent light

scattering data that indicates that the protein dynamics

couple to the glassy host, even in very viscous media [4].

When formulating a glassy matrix for preservation, it is

important to tune the high frequency coupling such that the

glass suppresses the protein dynamics. Previous folklore

implied that high Tg glasses make better preservation

materials. This was based on the notion that deeper in the

glassy state the protein would be more effectively suspended in a vitreous state of animation. However, a higher

Tg does not necessitate suppressed dynamics at the

relevant pico- to nanosecond time scales, as illustrated

here. Adding small amounts of glycerol to trehalose

decreases the Tg, but yields a superior preservation matrix.

References

[1] C. M. Henery, C&E News 78 (43), 85 (2000).

[2] M. T. Cicerone, A. Tellington, L. Trost, and A. Sokolov, BioProcess

Intl. 1 (1), 23 (2003).

[3] U. Buchenau and R. Zorn, Europhys. Lett. 18 (6), 523 (1992).

[4] G. Caliskan, D. Mechtani, S. Azzam, A. Kisliuk,

M. T. Cicerone and A. P. Sokolov, submitted.

4

3

2

1

0

log( deact/h) log( deact/h)

3.0 3.1 3.2 3.3 3.4

5

4

3

2

1

3.0 3.1 3.2 3.3 3.4

1000/T [1/K]

(b)

(c)

12

10

8

6

4

2

1/<u2> [Å-2]

3.0 3.1 3.2 3.3 3.4

(a)

250

200

150

E

100

a [kJ/mole]

0.00 0.02 0.04 0.06 0.08 0.10

glycerol

n ̊

n ̊

n ̊

H

H

H Y

Y

Y

(d)
18

Living cell membranes are made of

 phospholipids assembled in twodimensional bilayers in such a way that the

hydrophobic chains are being shielded from the

surrounding water as illustrated in Fig. 1. Due to

their extreme softness the phospholipid bilayers

exhibit thermal undulations in an aqueous environment

that give rise to repulsive forces between the cells or

between cells and substrates. These forces govern

important phenomena in the life process such as cell

coagulation and the ability of the cells to sense and react to

their surroundings. Here, we report results on the thermal

undulations of phospholipid bilayers obtained through the

Neutron Spin Echo (NSE) method, the only technique

covering the time scale of these motions, 1 ns to 10 ns

[1, 2].

The thermal undulations of phospholipid bilayers are

strongly dependent on the mechanical properties of the

bilayer such as the bending elasticity. Following earlier

studies by other methods [3, 4] we have studied the

dynamics of a model system, multilamellar vesicles (MLV,

see Fig. 1) in water, as a function of temperature, the

presence of cholesterol, and the presence of salt. Temperature is expected to influence several properties. Increase in

temperature decreases the solvent viscosity and increases

the thermal undulation amplitudes. The hydrophobic core

of the phospholipid membranes exhibits a sharp phase

transition from the crystalline to the liquid phase at a

certain temperature Tc that depends on the length of the

hydrophobic chains. Above Tc the interior of the phospholipid membrane is much more disordered and is expected

Bio-Membrane Flexibility Studied in

the Presence of Cholesterol and Salt

Fig. 1. Illustrations of a typical phospholipid (DMPC), a phospholipid

bilayer, a unilamellar vesicle and a multilamellar vesicle.

to be less rigid. Cholesterol, an important constituent of the

living cell, nestles in between the fatty tails, changing the

mechanical properties of the bilayers and hence their

motions. Finally, the presence of sodium chloride as an

electrolyte has a screening effect on electrostatic interactions and may affect the thermal undulations of electrostatically charged bilayers.

Three MLV samples are prepared for this study.

Sample I (“vesicles”), which serves as a reference, is a

MLV made mainly of 1,2-Dimyristoyl-sn-Glycero-3-

Phosphocholine (DMPC) in deuterated water (D2O) to

provide scattering contrast. The DMPC vesicles were

stabilized through enhanced electrostatic repulsion between

the bilayers by addition of a small amount (0.05 mol to

1 mol DMPC) of 1,2-Dimyristoyl-sn-Glycero-3-[Phosphorac-(1-glycerol)]-sodium salt (DMPG), a phospholipid that

is structurally similar to DMPC. In sample II (“vesicles &

chol”) cholesterol was added in the ratio of 0.3 mol

cholesterol to 1 mol of lipids. In sample III (“vesicles &

salt”) 0.05 mol L-1 of NaCl was added. MLV were prepared by extrusion through a filter with a 200 nm pore size

that predetermines their average diameter, as confirmed by

dynamic light scattering.

The NSE technique provides a measurement of the

real component of the intermediate scattering function in

the time domain I(Q,t). Thermal diffusive motions lead to

an exponential time decay of I(Q,t). Therefore we have

fitted our data for each sample at each temperature with

I(Q,t)/I(Q,0) = exp(-DeffQ2t), where the effective diffusion

coefficient Deff is a sum of two parts: Ddef, representing the

diffusive motions associated with the fluctuations within

each vesicle, the thermal undulations; and Dtr, the translational diffusion coefficient of the vesicles in the solution

[5]. The latter can be neglected because the vesicles

prepared here are quite large, R ≈ 100 nm, and according

to the Stokes-Einstein hydrodynamic equation the corresponding translational diffusion Dtr is less than

2.6 × 10-12 m2 s-1. Samples “vesicles” and “vesicles &

chol.” were studied at temperatures of 20 °C, 35 °C and

45 °C to cover regions below and above Tc of DMPC

which is 24 °C. Sample “vesicles & salt” was measured at

35 °C to study the effect of added electrolyte. Selected

results are shown on Fig. 2 and summarized in Table 1.

O

O

O

O

O O

P

O

N

H O

Lipid bilayer

Unilamellar vesicles (ULV) Multilamellar vesicles (MLV)

~100 nm

5 nm

Phospholipid (DMPC)
Chemical Physics and Biology

19

D. P. Bossev and N. S. Rosov

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899-8562

To take into account the effect of the solvent viscosity and temperature we have calculated the ratio Deffη/T and

normalized it to that at 35 °C. All deviations of the normalized parameter Deffη/T from 1 can be attributed solely to

the mechanical properties of the phospholipid bilayer and

are not related to changes in the viscosity of the surrounding water.

The analysis of the normalized parameter Deffη/T as a

function of temperature leads to the following conclusions

(see Fig. 3):

• Scaling the diffusion coefficient Deff that measures

the thermal undulations of DMPC bilayers like Deffη/T

mitigates the effects of temperature and the viscosity of

the surrounding fluid. Above the bilayer interior crystal/

liquid phase transition the scaled effective diffusion

coefficient for DMPC vesicles remains constant with

temperature.

• The bilayer liquid to crystalline phase transition

increases the rigidity of DMPC bilayers by a factor of 3 for

vesicles and by a factor of 1.5 for vesicles in presence of

cholesterol.

• Cholesterol increases the rigidity of the DMPC

bilayers in a bilayer-liquid state by a factor of 2 but has no

effect on the DMPC bilayers in a bilayer-crystalline state.

• Addition of 0.05 mol L-1 of NaCl reduces the

fluctuations of the DMPC bilayers by a factor of 2. This

effect can be attributed either to the reduced electrostatic

repulsion between the DMPC bilayers or to the effect of

the osmotic pressure that can deflate the MLV.

These results are in good agreement with those

obtained from other methods [3, 4]. They are a direct

confirmation that cholesterol stiffens cell membranes thus

reducing the cell — cell repulsions that originate from

undulation forces. The significant difference in the thermal

undulations below and above the bilayer liquid to crystalline

phase transition temperature shows the importance of

temperature for the proper functioning of the cell memFig. 2. Effective diffusion coefficient of DMPC vesicles as a function of

the scattering vector Q. Deff reflects mainly the thermal undulations of

the phospholipid bilayer.

Table 1. Effective diffusion coefficient of DMPC vesicles at different

compositions and temperatures.

Fig. 3. Effective diffusion coefficient of DMPC vesicles, scaled by the

solvent viscosity and temperature, and normalized to that at 35 °C.

Sample t/°C Deff × 1012 ηD2O × 103 Deffη/T

/m2 s-1 /N s m-2

vesicles 20 3.9 ± 0.7 1.25 0.30

vesicles 35 19.4 ± 4.6 0.871 1.00

vesicles 45 22.6 ± 3.9 0.714 0.92

vesicles & chol. 20 3.4 ± 1.1 1.25 0.26

vesicles & chol. 35 9.7 ± 2.6 0.871 0.50

vesicles & chol. 45 10.4 ± 1.2 0.714 0.43

vesicles & salt 35 11.7 ± 1.1 0.871 0.60

branes. Finally, it has been shown that the NSE method

provides a direct means of observing thermal undulation of

biological membranes.

References

[1] W. Pfeiffer, S. Köning, J. F. Legrand, T. Bayerl, D. Richter, and E.

Sackmann, Europhys. Lett. 23, 457 (1993).

[2] T. Takeda, Y. Kawabata, H. Seto, S. Komura, S. K. Shosh, M. Nagao,

and D. Okuhara, J. Phys. Chem. Solids 60, 1375 (1999).

[3] H. P. Duwe, and E. Sackmann, Physica A 163, 410 (1990).

[4] C. Hofsäß, E. Lindahl, and O. Edholm, Biophys. J. 84, 2192 (2003).

[5] S. T. Milner, and S. A. Safran, Phys. Rev. A 36, 4371 (1987).

35 x 10-12

30

25

20

15

10

5

0

Deff/m2s-1

0.06 0.08 0.10 0.12 0.14 0.16

Q/Å-1

 vesicles (35 oC)

 vesicles & chol. (35 oC)

 vesicles (20 oC)

Deff = 19.4 ± 4.6

Deff = 9.7 ± 2.6

Deff = 3.9 ± 0.7

1.2

1.0

0.8

0.6

0.4

0.2

D

η/T

20 25 30 35 40 45

t/oC

vesicles

vesicles & chol.

vesicles & salt

Phase

transition Presence of

cholesterol

Presence

of salt

Phase transition

temperature of DMPC

Cryst. Liq.
20

Dynamics of Glucose Solutions

I

n a process called cryoprotection,

 simple sugar molecules are produced

in response to desiccation or freezing by a

number of species of plants and animals specifically adapted to survive extreme cold or drought

[1]. The mechanism of this protective activity has

been much debated, with many theories invoking a

direct or indirect interaction with elements of cells such

as proteins and membrane bilayers. However, the fact

that a number of these sugars, such as the disaccharides

sucrose and trehalose, have unusually high glass transition

temperatures suggests that dynamical properties may also

play a contributing role in cryoprotection. For this reason,

information about the dynamics of sugars could be of

considerable interest for understanding cryoprotection.

The technique of quasielastic neutron scattering

(QENS) can probe motions such as molecular diffusion

and rotation on the nanosecond to picosecond timescales,

depending on the spectrometer. The wave vector and

energy dependences of the QENS signal provide information about the geometry of the motions as well as rates of

diffusion. Glucose is an appropriate subject for these

studies since it is the canonical sugar prototype as well as a

basic monomeric component of sucrose and trehalose.

The present work [2, 3] focuses on the effects of the

solute and solvent molecules through the choice of different energy windows and resolutions using the NCNR

backscattering (HFBS) and disk-chopper spectrometer

(DCS) instruments.

Selective H:D isotope substitution is a valuable tool

for sorting out the dynamics of a complex organic system

with QENS. Since the total bound-atom scattering cross

section for H (81.7 b) is much larger than that of D (7.6 b)

and most other atoms, the measured intensity is dominated

by the scattering from the H atoms. Moreover the scattering from H is 98 % incoherent so that the complicating

effects of interference in the scattering between different

atoms can generally be neglected.

Our analysis for both the glucose and water molecule

dynamics follows a model [4] that is based on the assumption that the vibrational, translational and rotational degrees

of freedom are dynamically independent. In practice, this

assumption results in a scattering function that is the sum

of two Lorentzians, one representing translational and the

Fig. 1. HFBS QENS spectra and fits (black line) of glucose/D2O

solutions at 280 K varying sugar to water ratios at Q = 0.99 Å-1. The

energy resolution at elastic scattering is 1.01 μeV. The narrow

Lorentzian corresponding to glucose translational motion (blue line) and

the broad glucose rotational Lorentzian (red line) are also shown.

other rotational motion. The latter gives rise to a peak too

broad to be accurately fit in the energy windows measured

in this experiment. In the incoherent approximation the

rapid jump diffusion model for the translational Lorentzian

has a full width at half maximum (FWHM) given by:

2Γt

 = 2hDQ2/(1 + Dτ0Q2), where D is the diffusion

constant and τ0 is the period between jumps. The two

Lorentzians were convolved with an instrumental resolution function to fit the measured spectra.

Since the dynamics of water molecules have been

found to be generally much faster than those of sugar

molecules, the motion of the two can be separated effectively through the judicious choice of energy window and

energy resolution of the instrument. To explore the

dynamics of the glucose molecules, the sugar, in which the

exchangeable hydrogen atoms had been pre-deuterated,

was dissolved in D2O and studied on HFBS with an energy

window of ±36 μeV. Even though the coherent scattering

cross section of water is comparable to the incoherent

cross section of glucose, the faster dynamics of the water

results in a broad contribution to the observed signal that

does not contribute to the translational motion lineshape.

Three aqueous glucose solutions were studied at

280 K with glucose to water ratios of 1:11, 1:20, and 1:55.

Two Lorentzians were used to fit the spectra (Fig. 1),

although the rotation component was generally too broad

to be accurately fit in the given energy window. The

effect of concentration on the glucose translational motion

-40.0 -20.0 0.0 20.0 40.0

E(μeV)

Intensity (arb. units)

1:11

1:20

1:55
Chemical Physics and Biology

21

L. J. Smith1, 2, C. Talon3,

 J. W. Brady4

, Z. Chowdhuri5, 6,

J. R. D. Copley5, D. L. Price7, M.-L. Saboungi3

1 Argonne National Laboratory, Argonne, IL 60439

2 Clark University, Worcester, MA 01610

3 Centre de Recherche sur la Matière Divisée, 5071 Orléans Cédex 2, France

4 Cornell University, Ithaca, NY 14853

5 NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899-8562

6 University of Maryland, College Park, MD 20742

7 Centre de Recherche sur les Matériaux

à Haute Température

45071 Orléans Cédex 2, France

Fig. 2. HFBS data probing glucose motion. The FWHM of the narrower

Lorentzian versus Q 2 for the three hydrogenated glucose solutions: 1:11

(closed circle), 1:20 (closed square), and 1:55 (closed diamond) at 280 K. Fig. 3. FWHM of the narrower Lorentzian corresponding to water

translational motion fitted to the QENS spectra for the various glucose

solutions at 280 K derived from DCS data at 110 μeV energy resolution

at elastic scattering. See the text for sample descriptions.

Both the glucose and water have similar degrees of

change in the translational diffusion constants, reflecting

the effect of hydrogen bonding on dynamics. Interaction

with glucose thus disrupts the organization of the water

molecules, as the retarding effect is observed for glucose

to water ratio as low as 1:55. These results hint at the role

that sugar may play in cryopreservation: in dry environments the binding of waters by sugar may prevent local

dessication, while in cold environments the sugar disruption of the water network may prevent local destruction by

favoring glass rather than ice formation.

References

[1] F. Franks Biophysics and Biochemistry at Low Temperatures;

Cambridge University Press: Cambridge (1985).

[2] L. J. Smith, J. W. Brady, Z. Chowdhuri, D. L. Price and

M.-L. Saboungi, submitted to J. Chem. Phys.

[3] C. Talon, L. J. Smith, J. W. Brady, J. R. D. Copley, D. L. Price,

M.-L. Saboungi, submitted to J. Phys. Chem.

[4] J. Teixiera, M.-C. Bellisant-Funel, S.-H. Chen, and A. J. Dianoux,

Phys. Rev. A. 31, 1913 (1985).

is evident. The narrow Lorentzian reduces in width with

increasing glucose concentration as the diffusive motion

slows. The FWHM for the two highest concentrations

was found to follow the random jump diffusion model

(Fig. 2) while the lowest concentration manifested the

characteristics of continuous diffusion: Γr = hDQ2. As the

concentration of the glucose increases, the diffusion rates

decrease by almost a factor of 6 from 25.1 ± 0.2 x 10-7

cm2/s for the 1:55 ratio solution to 4.5 ± 0.1 x10-7 cm2/s

for the 1:11 solution.

The larger energy window and energy resolution

(δE = 110 μeV) available on DCS permitted the examination of the water dynamics in aqueous glucose solution to

the exclusion of the glucose dynamics. The slower

dynamics of the glucose as observed on HFBS results in

the signal primarily contributing to an elastic peak on DCS.

To further minimize the incoherent contribution from the

glucose, the unexchangeable hydrogen atoms on the

molecule were replaced by deuterium atoms. Again three

different aqueous glucose solutions were studied with the

same ratios as on HFBS. In addition to the fully deuterated

glucose, glucose deuterated only at the C6 carbon atom

(d66glu) and deuterated glucose with a methoxy group at

the C2 carbon atom (mglu) were studied at the various

concentrations. The full width at half maximum of the

narrow Lorentzian from the fit, corresponding to the translational motion of the water molecules, had a Q2 dependence

typical of the random jump diffusion model (Fig. 3).

The diffusion rate dropped by a factor of 7 from

1.08 ± 0.02 x10-5 cm2/s for the 1:55 solution to

0.16 ± 0.01 x10-5 cm2/s for the 1:11 solution. A significant

difference in diffusion constant was not observed for

solutions that had glucose with deuterium substitutions,

further justifying the static approximation for glucose

motion on DCS.

0.0

20.0

40.0

60.0

80.0

0.0 1.0 2.0

FWHM (

μeV)

Q2 (Å-2)

1:55

1:20

1:11

0

100

200

300

400

500

FWHM (

μev)

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Q2 (Å-2)

water

glu55

glu20

glu11

d66glu11

mglu11
22

ATP-Induced Shape Change in a

Model Protein Complexed in Chaperonins

The role of molecular chaperones in

 mediating and controlling intracellular, as well as in vitro protein folding, has broad

implications for biotechnology. There is now

considerable insight into the possible mechanisms

whereby chaperone proteins recognize, stabilize, and

release unfolded polypeptide chains in a manner

whereby they are able to productively refold. However,

there are a number of important, fundamental gaps in the

understanding of chaperone action, which remain to be

resolved. Among the growing list of chaperone families

are the chaperonins GroEL (EL) and GroES (ES), which

have been intensively studied. Knowledge of how

misfolded protein substrates physically interact with EL

should provide vital clues necessary to unravel the process

by which EL mediates their proper folding. The ultimate

goal is to determine the mechanism by which EL transforms its substrate proteins and then releases them in a

form able to refold to their native conformation.

One of the key issues in establishing a molecular

mechanism for EL is to describe in structural terms the

conformations of polypeptide substrates when bound to

various chaperonin complexes. For example, does a nonnative polypeptide substrate unfold further upon binding to

EL? On the other hand, when a chain is released from EL

in the presence of the co-chaperonin ES, does it adopt a

more folded, or less folded conformation? These questions are difficult to resolve with naturally occurring

proteins since they refold so readily when released from

chaperonin complexes. One approach to address these

issues, however, is to utilize a family of mutationally altered

protein substrates that are unable to adopt their native

conformation. The nonnative subtilisin variant, PJ9 (p),

which is unable to refold when released, is one such

system that is readily available [1].

Single-ring EL mutants have been shown to assist in

the refolding of nonnative polypeptide chains [2, 3] and

they form unusually stable complexes with ES upon the

addition of nucleotides. Capitalizing on these properties, a

single-ring EL variant (sEL) was used to trap p within EL

by ES upon the addition of the nucleotides adenosine di- or

tri-phosphate (ADP or ATP). Small angle neutron scattering (SANS) experiments were then performed to examine

the structure of sEL/ES/p complexes and investigate

changes in p conformation in the presence of both nucleotides.

p was 86 % deuterated (dp) so that it contrasted

sufficiently with the chaperonin, allowing the contrast

variation technique to be used to separate the scattering

from the two components bound in the complex. The sEL

mutant assured that dp and ES were each bound in a 1:1

stoichiometry with the sEL, providing an advantage over

previous SANS experiments [4] which included mixed

stoichiometries of EL and ES.

Unlike ATP, ADP does not cause dissociation of dp

from EL. If dp is no longer covalently bonded to EL,

would its location in the EL/ES complex change? To

answer this question, two contrast variation series of

measurements, one with ADP and the other with ATP

present, were performed on the sEL/ES/dp complex [5].

Measurements were made in five D2O buffers in each

case, as shown in Fig. 1. The extensive I(Q) data sets in

Fig. 1 allow the separation of the scattering intensities from

each of the components in the complex and also the crossterm intensity. Modeling is then used to try to reproduce

these measured intensities.

Using this method, the location and approximate

shape of dp in the sEL/ES/dp + ADP complex was determined as modeled in Fig. 2. The significant result is that

the dp component has an asymmetric shape: part of the

polypeptide must extend beyond the cavity inside the sEL

ring up into the space surrounded by ES. The best fit to

the data from both complexes (i.e., with ADP or ATP) was

Fig. 1. Contrast variation data from sEL/ES/dp complexes a) + ADP and

b) + ATP in 100 % (z), 85 % (), 70 % (+), 20 % (O) and 0 % () D2O

solutions. The data in 20 % and 0 % D2O solution are shifted by the

factor 0.1, as indicated, for clarity.

I(Q)

1

0.1

0.01

0.001

0.0001

0.00 0.10 0.20 0.00 0.10 0.20

a b

(x0.1)

(x0.1) (x0.1)

(x0.1)

Q (Å-1)
Chemical Physics and Biology

P(r)

0 10 20 40 50 60

r (Å)

30

0.00

0.20

0.40

0.60

0.80

1.00

sEL

ES

dp

23

S. Krueger

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899-8562

S. K. Gregurick

University of Maryland, Baltimore County

Baltimore, MD 21250

J. Zondlo and E. Eisenstein

Center for Advanced Research in Biotechnology

University of Maryland Biotechnology Institute

Rockville, MD 20850

achieved using one ring of the EL/ES solution structure of

Ref. 6 for the sEL/ES component of the complex, one ring

of the x-ray structure for EL of Ref. 7 for the free sEL,

and the x-ray structure for free ES of Ref. 8 in a ratio of

75:21:4 by mass.

The significant difference in the sEL/ES/dp complex

formed from ATP is that the shape of the bound dp

molecule changes from an asymmetric shape such as that

shown in Fig. 2 to a more symmetric shape. Figure 3

shows the distance distribution functions obtained by

Fourier inversion of the I(Q) for bound dp in both the sEL/

ES/dp + ADP and sEL/ES/dp + ATP complexes. The most

probable distance increases from approximately 22 Å to

30 Å, with a similar increase in the radius of gyration, Rg,

from 19.0 ± 0.5 Å to 21.0 ± 0.5 Å.

The shape of dp in the presence of ATP is clearly

more symmetric, as indicated by the greater symmetry of

the distance distribution function. This suggests that dp is

transformed into a more expanded form in the ATP complex. However, the symmetry of this curve cannot be used

to unambiguously assign a shape to dp in the ATP complex.

Because the sEL/ES/dp complex dissociates in solution,

which contains about 21 % of sEL/dp complex, it is

possible that the distance distribution curve represents a

composite of data from dp bound to sEL alone and to the

sEL/ES complex formed from ATP. For the same reason,

it is unclear from the data whether dp is still located

partially in the sEL cavity. However, what is clear is that

there has been a transformation in the shape of dp associated with the complex formed from ATP. The dp shape

change was significant enough to be detected as a change

in the shape of the scattering from this component, in spite

of the fact that dissociation is likely to be present in the

sample. A conformational change of dp either was not

supported by the complex formed from ADP or was

insufficient to generate a lasting change in shape in that

case, and dp instead relaxed back to a form close to its

original conformation. This important observation reflects

the relative ability of ATP to promote refolding of protein

substrates relative to ADP.

References

[1] Z. Lin and E. Eisenstein, Proc. Natl. Acad. Sci. USA 93, 1977

(1996).

[2] I. S. Weissman, Chem. Biol. 2, 255 (1995).

[3] S. G. Burston, J. S. Weissman, G. W. Farr, W. A. Fenton and

A. L. Horwich, Nature 383, 96 (1996).

[4] P. Thiyagarajan, S. J. Henderson, and A. Joachimiak, A, Structure 4,

79 (1996).

[5] S. Krueger, S. K. Gregurick, J. Zondlo and E. Eisenstein, J. Struct.

Biol. 141, 240 (2003).

[6] R. Stegmann, E. Manakova, M. Rossle, H. Heumann, S. E. NiebaAxmann, A. Pluckthun, T. Hermann, R. P. May and

A. Wiedenmann, J. Struct. Biol. 121, 30 (1998).

[7] K. Braig, Z. Otwinowski, R. Hegde, D. C. Boisvert, A. Joachimiak,

A. L. Horwich and P. B. Sigler, Nature 371, 578 (1994).

[8] J. F. Hunt, A. J. Weaver, S. J. Landry, L. Gierasch, and

J. Deisenhofer, Nature 379, 37 (1996).

Fig. 2. Side view of a model for the sEL/ES/dp + ADP complex

constructed from SANS contrast variation and crystallography data.

The sEL/ES complex is represented by the red ribbon structure and the

dp is represented by the blue spheres.

Fig. 3. Normalized distance distribution functions for dp bound to

sEL/ES complexes + ADP () and + ATP ().
24

Biomimetic membranes have been

 developed as models of living cell

membranes, and this has applications in the

quest for biocompatibility of inorganic materials in

biologically active mediums, such as coatings for

artificial organs. A membrane consists of a lipid

bilayer (two lipid layers) where hydrophobic carbon

chains form the inside of the membrane and their polar

head groups the interface with the aqueous surrounding

medium. A supported membrane-mimic consists of a lipidlike bilayer, typically attached to a single-crystal substrate,

with access to water only at the top surface [1, 2]. Here

we use neutron reflectometry to study a system in which

water has access to both sides of a membrane-mimic

attached to such a substrate, thus making the system a

closer mimic to a real cell membrane.

The system devised by Liu et al. [3] consists of a

water-swellable polyelectrolyte that electrostatically binds

to the substrate and acts as a “cushion” for the membrane,

not unlike the cytoskeletal support found in actual mammalian cell membranes. The lower half of the membranemimic is a terpolymer that attaches to the polyelectrolyte.

A phospholipid layer forms on top of the terpolymer and

the bilayer is finally chemically crosslinked for added

stability. The system is shown schematically in Fig. 1.

Neutron reflectivity measurements were performed at

the NG-1 vertical stage reflectometer to obtain the compositional profile at every step of the assembling process of

the membrane-mimic which consisted of three stages: a)

polyelectrolyte multilayer (PE), b) polyelectrolyte multilayer

Phase Sensitive Neutron Reflectometry

on a Water-Cushioned Biomembrane-Mimic

Fig. 1. Schematic diagram of a biomimetic membrane. The

phospholipid layer at the top combines with the terpolymer layer to form

a membrane-mimic that in turn resides on the water (blue dots)

permeable “cushion” polyelectrolyte multilayer. The latter attaches

electrostatically to the Au-capped substrate.

plus terpolymer (PE+TER), and c) polyelectrolyte multilayer plus terpolymer plus phospholipid layer

(PE+TER+PC) [4]. The spatial resolution attained was

approximately 10 Å, about half the thickness of a membrane bilayer, making it possible to distinguish the two

layers of a membrane but not the structure of a single

layer.

A unique compositional profile of the biomimetic film

with no a priori knowledge of the sample’s composition is

obtained by measuring the reflectivity of equivalent

samples made onto two substrates [5]. The substrates

used were single crystal silicon (Si) and sapphire (Al2O3)

coated with chromium (Cr) and then a gold (Au) layer to

allow the polyelectrolytes to bind to a similar surface on

both wafers.

Figure 2 shows the compositional profiles for the PE,

PE+TER and PE+TER+PC assemblies in a D2O atmosphere at 92 % relative humidity. The figure shows that

the hydration of the PE layer is almost unaffected by the

addition of the terpolymer and the phospholipid layer. Also,

upon the addition of the phospholipid layer to the PE+TER

assembly, the composite PE+TER+PC assembly shows an

increase in thickness of approximately 30 Å, consistent

with the formation of a single phospholipid layer at the

surface. It is also clear that the addition of a phospholipid

layer onto the terpolymer layer rearranges this region

Fig. 2. Compositional profile of biomimetic membrane in a D2O

atmosphere at 92 % relative humidity at various stages of assembly on

Au-capped substrate: only polyelectrolyte (PE), polyelectrolyte and

terpolymer (PE+TER), polyelectrolyte, terpolymer and phospholipid

(PE+TER+PC). The compositional profile is given by the scattering

length density, SLD, profile when using neutrons. PE

Terpolymer

Phospholipid

Cr

0

1

2

3

4

5

0 50 100 150 200

PE

PE+TER

PE+TER+PC

Au

Z (Å)

92 % humidity D2O

Scattering length density (x10-6

Å-2)

Substrate

Cr/Au layers

Polyelectrolyte Multilayer

Phospholipid

Terpolymer
Chemical Physics and Biology

25

U. A. Perez-Salas

NIST Center for Neutron Research

National Institute of Standards and Technology, Gaithersburg, MD 20899-8562

K. M. Faucher

Emory University School of Medicine, Atlanta, GA 30322

C. F. Majkrzak, N. F. Berk, S. Krueger

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899-8562

E. L. Chaikof

Emory University School of Medicine

Atlanta, GA 30322

Fig. 3. Scattering length density profiles (top) and water fraction

(bottom) for PE+TER+PC under indicated conditions.

significantly, since the terpolymer layer only becomes

apparent after the phospholipid layer is added. It is possible

to verify with an independent technique (contact angle)

that the terpolymer was in fact deposited because it forms

a hydrophobic outer layer. The outer surface becomes

hydrophilic once the phospholipid layer is deposited onto

the terpolymer layer.

Figure 3 (top) shows the profile for the PE+TER+PC

assembly under 92 % relative humidity in 100 % D2O and

in 50/50 D2O/H2O. The overall thickness change due to the

intake of water, in going from dry (not shown) to 92 %

relative humidity, was found to be 20 Å. Figure 3 (bottom)

shows the water fraction in the assembly under 92 %

relative humidity. This is obtained by assuming that the

distribution of each component in the layers is unaffected

by having either D2O or 50/50 D2O/H2O. From the figure it

can be seen that the polyelectrolyte multilayer has a 40 %

water uptake. This is a significant amount of water, which

suggests that the polyelectrolyte multilayer can work as a

“cushion” for membrane-mimetic systems. The terpolymer

and the phospholipid layers contain an average of 10 %

water, which is also significant, suggesting that these

layers are not tightly packed.

The method of making equivalent samples on two

substrates to obtain a unique compositional profile has a

built-in congruency test, particularly useful in checking the

reproducibility of the samples as well as the quality of the

films. The test is to compare the calculated imaginary part

of the complex reflectivity from the obtained profile with

the corresponding data, as is shown in Fig. 4 for the

PE+TER and PE+TER+PC assemblies. From Fig. 4 it is

concluded that the PE+TER samples are homogenous and

essentially identical while for the PE+TER+PC assembly, the

Fig. 4. Imaginary part of the complex reflectivity, Im r (Q), data

(symbols) and calculated curves (lines) obtained from the SLD profiles

for the PE+TER and the PE+TER+PC assemblies shown in Fig. 2.

absence of true zeros, as indicated by the calculated curve, is

suggestive of a small degree of sample inhomogeneity.

The system from Liu et al. has many characteristics

desirable in a biomimetic membrane. It is a single membrane-mimic attached to a significantly hydrated soft

“cushion” support that allows some membrane proteins to

function. Thrombomodulin, a membrane protein relevant to

blood-clotting, is being studied in this membrane-mimic

environment to further develop biocompatible coatings for

artificial organs [6].

References

[1] E. Sackmann, Science 271, 43 (1996).

[2] A. L. Plant, Langmuir 15, 5128 (1999).

[3] H. Liu, K. M. Faucher, X. L. Sun, J. Feng, T. L. Johnson, J. M.

Orban, R. P. Apkarian, R. A. Dluhy, E. L. Chaikof, Langmuir 18,

1332 (2002).

[4] U. A. Perez-Salas, K. M. Faucher, C. F. Majkrzak, N. F. Berk,

S. Krueger, E. L. Chaikof, Langmuir 19, 7688 (2003).

[5] C. F. Majkrzak, N. F. Berk, U. A. Perez-Salas Langmuir 19, 1506

(2003).

[6] J. Feng, P. Y. Tseng, K. M. Faucher, J. M. Orban, X. L. Sun,

E. L. Chaikof, Langmuir 18, 9907 (2002).

-0.03

0

0.03

0.06

(a)

-0.06

-0.03

0

0.03

0.06

0 0.05 0.1 0.15 0.2 0.25 0.3

Im r

(b)

Im r

PE+TER+PC

PE+TER

92 % humidity D2O

Q [Å-1]

PE+TER+PC at 92 % humidity

0

1

2

3

4

5

Water Fraction

PE

TerpolymerPhospholipid

0

0.2

0.4

0.6

0.8

1

0 100 150 200 Cr Au

50

Z (Å)

50/50 D2O / H2O

100 % D2O

Scattering lengthdensity (x10-6Å-2)
26

We have been engaged in an inter-

 disciplinary materials research

effort to develop new classes of biomaterials

that are constructed via designed molecular selfassembly [1]. These materials use specific polypeptides that are designed a priori to self-assemble into

targeted nano- and microscopic structures. Using

amino acids as the fundamental material building blocks,

one can potentially engineer materials having targeted

biological functions such as in vivo therapeutic delivery or

tissue scaffolding. Materials can be designed whose

morphology is responsive to specific environmental cues.

The ability to actively manipulate material morphology can

lead to “smart” materials whose structure and consequent

biological function is responsive to environmental cues.

Predictable control of material morphology would be a

significant advance in the development of functional

biomaterials because it would provide active control of

biological properties that are dependent on an aggregate’s

shape or size. An example of molecular design for a

specific application would be in the delivery of drugs and

genes, where the shape of the delivery assembly favors

selective interactions with different biological surfaces,

e.g., an active gating mechanism induced by a predicted

external stimulus.

Polypeptides, composed of amino acids each of

which imparts a unique structural and/or functional

characteristic to the polymer molecule, provide an imBiomaterials Constructed

Via Designed Molecular Self-Assembly

mense molecular toolbox from which one can construct

functional materials via self-assembly. The primary tools

exploited are the conformational propensities of individual

amino acid residues to adopt desired secondary structures

or shapes and the tendency of the appropriately designed

secondary elements to self-associate (Fig. 1). It is now

possible to design peptides that will fold into stable secondary structures such as α-helices (rod-like polymers that

typically form nematic liquid crystals in solution and pack

as hexagonal arrays of rods in the solid-state) and β-sheets

(crystalline arrays of extended chains, mainly stabilized by

H-bonding). It is also possible to design polypeptides that,

in addition to intramolecular folding, undergo self-assembly

to construct higher order structures.

Currently we are studying the self-assembly behavior

of both charged and neutral amphiphilic di- and tri-block

copolypeptides. Unlike membrane-forming lipids and

surfactants, the neutral copolypeptides form robust bilayer

membranes in aqueous solutions over a wide range of

molecular weights and molar ratios. This has been

observed in amphiphilic, nonionic, completely α-helical

peptide block polypeptides at all of the molecular weights

(20k g/mol to 60k g/mol) and molar ratios (ranging from

90/10 hydrophilic/hydrophobic to 60/40) studied. Diblocks

of poly-L-lysine (K), with short ethylene glycol side chains

Fig. 1. a) Schematic of peptide monomers chemically bonded to form

diblock, triblock and random copolymers; b) Amphiphilic

copolypeptides self-assembled in micelles; c) Copolypeptides physically

linked to form a hydrogel; and d) typical copolypeptide chain

architectures [4].

Fig. 2. SANS from amphiphilic diblock copolypeptides showing the

change from threadlike morphology (I (q) ~ q -1) when the hydrophobic

block is an α-helix (lower curve), to sheetlike morphology (I (q) ~ q -2)

when the hydrophobic block is more like an extended β-sheet (upper

two curves).

PL10 0.5 wt% in D2O

P-L/V40 0.5 wt% in D2O

PV10 0.5 wt% in D2O

.001 .01 .1

-2

-1

103

102

10

1

10-1

10-2

10-3

10-4

Intensity

q (Å-1)
Soft Condensed Matter

K-LV SANS

a) c) 102

10

1

10-1

10-2

10-3

10-4

10-3 10-2 10-1 1

q (Å-1)

I (cm-1)

I(q) ~ As/q4

-3.9

-2.2 1.0 mass %

0.4 mass %

q (Å-1)

10-5 10-4 10-3 10-2

1010

109

108

107

106

105

104

103

I(q) cm-1

q* b)

-1

-2

5.0

2.0

1.0

0.5

27

D. J. Pochan, J. P. Schneider, L. Pakstis, B. Ozbas

University of Delaware, Newark, DE

A. P. Nowak and T. J. Deming

University of California at Santa Barbara

Santa Barbara, CA

(PEGLys) (P) as a nonionic block, joined with hydrophobic

polyleucine (L) form fluid bilayers and also spontaneously

form vesicles. On the other hand, PLP triblocks form

extremely rigid, high aspect ratio membranes. Rigid

membranes preclude use in therapeutic delivery assemblies

but provide intriguing possibilities for synthetic biomaterial

scaffolding in more concentrated suspensions.

A SANS study of secondary structure effects shows

a large transition in the assembled structure induced by

changing the minority hydrophobic block from an α-helix,

polyleucine (L), to an extended β-sheet former, polyvaline

(V). For the V-rich case the amphiphiles assemble into

thread-like micelles with a large interfacial curvature

between blocks. This is reflected in the blue curve of

Fig. 2 with I(q) ~ q-1. For the L-rich cases (green and red

curves of Fig. 2) flat lamellar geometry in the membranes

and vesicles is favored, with I(q) ~ q-2. The result indicates that the interfacial area of the respective blocks (large

for the leucine α-helix, small for the extended valine

β-sheet) plays an important role in the interfacial curvature

and the resultant structure formed, similar to what is

observed in lipid self-assembly.

In addition to the bilayer/membrane forming nonionic

polypeptides, hydrogel formation of charged, amphiphilic

block polypeptides is observed. By removing the PEG side

chain from poly-L-lysine, one obtains a polycationic lysine

block at neutral pH. Block polypeptides of lysine and

leucine form strong hydrogels at low molecular weights

(20k g/mole) and concentrations (< 0.006 mass fraction),

both an order of magnitude lower than observed in traditional polymeric hydrogel formation. The structural

characterization of these unique gels is crucial to uncovering their gelation mechanism and in the design of new gel

Fig. 3. a) SANS from hydrogels of diblock copolypeptides showing a diffraction peak

corresponding to a regular repeat spacing in the self-assembled gel matrix; b) Cryo-TEM

image of the .01 mass fraction hydrogel (the scale bar is 200 nm); c) USANS data showing

the large drop in scattered intensity when the concentration of peptide falls below the

gelation threshold (≈ 0.5 mass %).

formers with the added control/environmental

responsiveness discussed above. Gelation

occurs with a variety of hydrophobic block

secondary structures but with varying degrees

of strength [2]. Both SANS and USANS

measurements at the NCNR have been

indispensible for probing the global nano- and

microstructure of these porous hydrogel

materials.

In some cases, the self-assembled gels

exhibit a characteristic spacing in the underlying scaffold. An example of this is observed in

Fig. 3 where the correlation peak shifts to

lower q with decreasing concentration,

indicating that the regular structure persists

even as the characteristic spacing increases

[3]. On the microscale, the hydrogels exhibit clear smooth

surface scattering with I(q) ~ q-4 as determined by USANS

(Fig. 3c). When the peptide concentration drops below the

gelation threshold (≈ 0.005 mass fraction) the material

becomes a viscous liquid, and the USANS scattering drops

significantly in slope indicating the loss of well-defined

microstructure in the materials [3].

We have also investigated the dynamics of the

gelation process [1]. In a rheometer, the gel structure was

disrupted by large amplitude oscillations, but recovered

90 % of full strength within seconds of cessation of shear.

The low mass fraction of material in the polypeptide

hydrogels, combined with their recovery properties and

microporous structure, allows them to fill an advantageous

and unique niche between conventional polymer and

surfactant hydrogels. Their peptide backbone also imparts

to these materials some of the advantageous features of

proteins (such as degradability and functionality), which

makes them attractive for biomedical applications.

References

[1] A. P. Nowak, V. Breedveld, L. Pakstis, D. J. Pine, D. J. Pochan,

T. J. Deming, Nature 417, 424 (2002).

[2] J. P. Schneider, D. J. Pochan, B. Ozbas, K. Rajagopal, L. M. Pakstis,

J. Gill, J. Am. Chem. Soc. 124, 15030 (2002).

[3] D. J. Pochan, L. Pakstis, B. Ozbas, A. K. Nowak, T. J. Deming,

Macromolecules, 35, 5358 (2002).

[4] J. Kopecek, Nature 417, 388 (2002).
28

The key step in assembling colloidal

 particles into useful structures for

applications as coatings, viscosity modifiers,

and gels, for example, lies in fine-tuning particle

interactions to produce the desired microstructure.

The distinct advantage of adding non-adsorbing

polymer to a colloidal suspension (particles of radius R)

lies in the ability to control the microstructure of the

resulting dispersion with two independent variables — the

molecular weight of the added polymer (radius of gyration

Rg) which controls the range of particle interactions and

the concentration of added polymer (cp) which controls the

strength of particle interactions. Recent studies [1, 2] have

shown that a wide range of phase behavior can be observed in colloidal dispersions depending on the values of

Rg/R and cp/cp

* (cp* is the polymer overlap concentration).

For Rg/R < 0.1, the suspensions gel as more polymer is

added to the system. For 0.1 < Rg/R < 0.3, the colloids

crystallize and for higher size ratios (Rg/R > 0.3) a liquidliquid phase separation is thermodynamically favored.

Standard theories in literature fail to predict the observed

trends in phase behavior and we have recently shown that

the only model that can qualitatively predict the observed

experiments is the polymer reference interaction site model

(PRISM) integral equation theory for colloid-polymer

mixtures [1, 2].

In this work we report on Small Angle Neutron

Scattering (SANS) and Ultra Small Angle X-Ray Scattering

(USAXS) studies of the structures of model colloidpolymer suspensions over a wide range of Rg/R and cp/cp

*.

Our aim in measuring the structure is twofold: to provide a

test of different models especially PRISM for predicting

the thermodynamics and structure of colloid-polymer

mixtures; and to relate the observed microstructure to

macroscopic flow properties (shear modulus, viscosity)

especially under conditions where the suspensions gel.

The system used in this work consists of 100 nm

diameter silica particles coated with octadecanol (1 nm to

2 nm hairs) and suspended in decalin. The particles in the

absence of added polymer behave as hard spheres (no

interactions except volume exclusion). The polymer used

is polystyrene of different molecular weights to provide the

appropriate Rg/R. Figures 1 and 2 are plots of the meaScattering Studies of the Structure

of Colloid-Polymer Suspensions and Gels

sured intensities and the calculated structure factors at an

Rg/R of 0.06 and different values of cp/cp

*. The solid lines

are comparisons with structure factors from PRISM

theory for colloid-polymer mixtures. Agreement with

theory and experiment is excellent for samples in the

single- phase fluid region thus establishing the fact that

PRISM accurately predicts the thermodynamics and

structure of these suspensions in the q region of interest.

At a colloid volume fraction of 0.4 and Rg/R of 0.06,

the suspensions gel at a cp/cp

* of 0.095. Shown in Fig. 2 is

the measured structure factor in the gel phase at a cp/cp

* of

0.1. When particles become frozen in the gel state, they

fall out of equilibrium and comparisons with theory worsen

as is evident from Fig. 2. Another interesting characteristic

about these gels is the high upturns in intensity at low

angles. Fractal analysis gives an unphysical dimension of

3.4 that led us to propose a model of clusters of particles

Fig. 1. Normalized scattering intensities I (q) as a function of q (Å-1) for

samples with varying amounts of polymer quantified by the

dimensionless polymer concentration cp /cp*. The colloid volume

fraction is fixed at φ = 0.40 ± 0.01, and Rg /R = 0.053. Data is shown for:

cp /cp* = 0 (hard spheres, crosses), 0.08 (equilibrium fluid, squares), and

0.1 (Gel, triangles). Experimental data (diamonds) for the form factor

(single particle scattering) is also shown. As more polymer is added to

the system, intensities at low angles increase indicating the presence of

clusters/aggregates and an increased compressibility.

10-3 10-2 10-1

q(Å-1)

I(q) 107

106

105

104

103

102

101

100

10-1

Rg/R = 0.053

Form Factor ( = 0.02)

cp/cp

* = 0 : Hard Sphere

cp/cp

* = 0.08 : Eq. Fluid

cp/cp

* = 0.1 : GEL

cp/cp

*

= 0.4
Soft Condensed Matter

29

S. Ramakrishnan, S. A. Shah, Y. L. Chen,

K. S. Schweizer, and C. F. Zukoski

University of Illinois at Urbana-Champaign

Urbana, IL 61801

with randomly distributed voids throughout the gel sample

(Debye-Bueche analysis). The cluster size in these

samples is ≈ 5 to 8 particle diameters as calculated from

the scattering curves. This finding has an important

consequence when trying to predict the flow properties of

these suspensions especially the elastic modulus as clusters

reduce the ability to store energy compared to an open

network of particles. More detailed discussions about the

structure and its links to rheology can be found in references [3–5].

The above scattering experiments performed at the

NCNR and at Argonne National Laboratory were the first

systematic studies of the structure of a model colloidpolymer suspension. These experiments helped us validate

the use of PRISM theory for colloid-polymer mixtures.

We now have a predictive capability for the variety of

interesting phenomena, such as phase transitions between

qualitatively different glassy states and reentrant melting of

colloidal crystals, observed in these colloid-polymer

mixtures.

References

[1] S. Ramakrishnan, M. Fuchs, K. S. Schweizer and C. F. Zukoski,

J. Chem. Phys. 106, 2201 (2002).

[2] S. A. Shah, Y. L. Chen, K. S. Schweizer and C. F. Zukoski, J. Chem.

Phys. 118, 3350 (2003).

[3] S. A. Shah, S. Ramakrishnan, Y. L. Chen, K. S. Schweizer and

C. F. Zukoski, Langmuir 19(12), 5128 (2003).

[4] S. A. Shah, Y. L. Chen, S. Ramakrishnan, K. S. Schweizer and

C. F. Zukoski, J. Phys. Condensed Matter 15(27), 4751 (2003).

[5] S. A. Shah, Y. L. Chen, K. S. Schweizer and C. F. Zukoski, to be

published in J. Chem. Phys.

Fig. 2. Structure factor S (q) as a function of the dimensionless

wavevector qD (diameter D = 100 nm) for samples: cp /cp* = 0.0 (hard

spheres, crosses), 0.08 (equilibrium fluid, squares), and 0.10 (Gel,

triangles), for the same φ and Rg /R as Fig. 1. Each subsequent data set is

offset by 1 for clarity. Dotted lines show relevant baselines signifying

S (q) = 0 for each data set. Solid lines are the zero-adjustable parameter

PRISM-mPY theory predictions. The structure factor which depicts the

packing of particles with respect to each other in solution is calculated

from the data of Fig. 1 by dividing the intensities of the respective

suspensions by that of the form factor and then multiplying by the ratio

of the volume fractions (φFormFactor /φ Sample = 0.02/0.4) [3, 4]. The

location of the first peak (q*) in the structure factor shifts to higher q’s

as more polymer is added to the system indicating that the particles are

getting closer to each other on an average. When the suspension gels,

the particles are frozen in space and q* is constant with added polymer

as one traverses deeper into the gel [3, 4]. The increased S (0) for the gel

sample is indicative of increased compressibility in the system due to

clustering of particles (cluster size ≈ 5–8 particle diameters). The

structure of the gels based on the calculated S (q) is hypothesized to

consist of clusters of particles with randomly distributes voids which

gives rise to the steep upturns in S (q) at low q [3, 4].

0

1

2

3

4

5

6 8 10

S(q)

qD

024

cp/cp

* = 0 : Hard Sphere

cp/cp

* = 0.08 : Eq. Fluid

cp/cp

* = 0.1 : GEL

 = 0.4

Rg/R = 0.053
30

Spinons, Solitons, and

Breathers in Spin-1/2 Chains

Fig. 1. Qualitative illustration of spinons in a spin-1/2 chain. (a) Shows

a spin-flip excitation in an otherwise ordered segment of a spin chain. In

the subsequent two frames the spin-flip is spatially separated into

domain wall boundaries illustrating spinons that each carry half a spin

flip. Separation of the walls costs no energy. (d) shows the situation

when a staggered field (small black arrows) breaks the symmetry

between even and odd sites of the lattice. Spinons now attract each

other (separation costs energy) and can be expected to form bound

states. Note that in a real spin-1/2 chain spinons are dynamic quantum

degrees of freedom with a finite spatial extent.

energies for spinon pairs that can carry the linear momentum delivered by the neutron.

Spinons also lead to remarkable properties in a nonzero magnetic field. While a classical antiferromagnet

develops magnetization through uniform canting of

otherwise antiferromagnetic spins, the magnetization of a

spin-1/2 chain is carried by a finite density of spinon like

defects. The average distance between these magnetized

defects defines a characteristic field dependent length scale

which is manifest in the neutron scattering data as a q-shift

in the longitudinal part of the zero field sinusoidal ridge of

scattering. The result is a set of overlapping gapless

continua. Predicted more than 20 years ago, the effect

found its first experimental realization this year at the

NCNR [2]. The data shown in Fig 2(b) were acquired

under the same conditions as Fig. 2(a) though with the

spin chain in a magnetized state induced by an external

field. There is no complete theory for these data but it was

recently shown that much of the spectral weight can be

associated with the two-particle continuum of the high

field version of spinons called psinons [4]. Comparison of

the data in Fig. 2(b) to this theory however reveals that

there is spectral weight close to q = π that cannot be

accounted for by psinons [2]. Theoretical work is now

Fig. 2. False color image of SPINS neutron scattering data [2] from

Cu(C4H4N2)(NO3)2 (CuPzN) in zero and high field. Spin-1/2 copper atoms

shown in red form uniform chains. The experiment provides evidence

for a two-particle continuum from spin-1/2 particles with a field

dependent chemical potential. The solid lines show boundaries for

various types of continua determined through Bethe Ansatz and exact

diagonalization.

(a) 

(b) 

(c) 

(d) 

No matter how strong the nearest

 neighbor antiferromagnetic

interactions, quantum fluctuations prevent

static long-range order within an infinite line of

spin-1/2 quantum moments. What at first blush

appears to be the simplest possible antiferromagnet,

thus turns out to be a unique correlated spin liquid [1].

The structures of two materials with this extraordinary

brand of dynamic magnetism are illustrated above Figs. 2

and 3. Figs. 2(a) and 3(a) show zero field inelastic neutron

scattering data from these materials as a function of energy

transfer, hω, and wave vector transfer, q. For conventional

magnets such data feature a sharp sinusoidal ridge through

the q-ω plane, which is evidence for coherent spin wave

excitations. While a ridge is also visible in the present data,

its energy width greatly exceeds the experimental resolution. The implication is that neutrons cannot create coherent excitations in spin-1/2 chains. This is a surprise given

that mobile domain walls called spinons are known to be

well-defined excited states carrying heat and momentum

over macroscopic distances. The paradox is resolved by

recognizing that a spinon is actually just half of a spin flip

(see Fig. 1 (a)-(c)). Two spinons are needed to scatter a

neutron, and the broadened spectrum reflects the range of

0 0.25 0.5 0.75 1 0 0.25 0.5 0.75 1

(b) H = 8.7 T 3

2

1

0

h (meV)

q / π ~ q / π ~

(a) H = 0 T
Condensed Matter and Applied Physics

31

C. Broholm1,2, Y. Chen3, M. Kenzelmann1,2, C. P. Landee4, K. Lefmann5,

Y. Qiu2,6, D. H. Reich1, C. Rischel7, M. B. Stone8, and M. M. Turnbull4

1 Johns Hopkins University, Baltimore, MD 21218

2 NIST Center for Neutron Research

National Institute of Standards and Technology, Gaithersburg, MD 20899-8562

3 Los Alamos National Laboratory, Los Alamos, NM 87545

4 Clark University, Worcester, MA 01610

5 Risø National Laboratory, DK-4000 Roskilde, Denmark

6 University of Maryland, College Park, MD 20742

7 Niels Bohr Institute, University of Copenhagen

DK-2100, Copenhagen, Denmark

8 Pennsylvania State University

University Park, PA 16802

Fig. 3. False color image of DCS neutron scattering data [3] from

CuCl2 · 2(dimethylsulfoxide) (CDC) in zero field and in a field of 11 Tesla.

Spin-1/2 copper atoms shown in red form spin chains with alternating

orientation of the coordinating environment, causing an effective

staggered field in registry with the lattice in conjunction with the

uniform field. The staggered field causes formation of soliton and

breathers from spinons as evidenced by resolution limited modes with a

finite energy gap.

under way to determine the nature of the corresponding

excitations.

Static long-range order in the antiferromagnetic spin

chain implies breaking the symmetry between odd and

even sites of the lattice. As noted above, this does not

occur spontaneously in a spin-1/2 chain but an applied field

that alternates from site to site does break the symmetry

and can therefore be expected to have a pronounced effect

on both static and dynamic properties. Surprisingly, a

staggered field is not hard to achieve. When even and odd

sites along the spin chain have differently oriented atomic

coordination environments, application of a uniform field

induces an accompanying staggered field.

The molecular magnet CuCl2 · 2(dimethylsulfoxide)

(CDC) has alternating coordination environments and Fig.

3(b) shows the dramatic effects on the neutron scattering

spectrum in a field [3]. The zero field two spinon continuum coalesces into resolution limited modes with

different energy gaps at q = π and at the incommensurate

wave vector. The staggered field breaks the domain

symmetry (Fig. 1(d)), favoring antiferromagnetic domains

that are aligned with the applied staggered field. If the

domain between two spinons is out of phase with the

staggered field the spinons attract each other. The strength

of interaction grows with spinon separation resulting in

asymptotically bound spinons. Because they consist of

spinon pairs, these bound states can be created directly

through neutron scattering.

Following the initial discovery of a field induced gap

in a spin-1/2 chain at the NCNR [5], Affleck and Oshikawa

showed that the relevant low energy field theory describing

bound spinons is the quantum sine-Gordon model [6]. It

can be shown that the excited states at the incommensurate wave vector in the spin-1/2 chain are topological

excitations called solitons, while those at q = π are soliton

bound states called breathers. Identifying the lowest energy

excitation at the incommensurate wave vector with a

soliton, the quantum sine-Gordon model perfectly accounts

for the energy of the two lower excitations at q = π as

being the corresponding breathers. The agreement between

the observed excitation energies and the predictions of the

quantum sine-Gordon model persists throughout the field

range that we have accessed, which corroborates the

identification of both excitations [3]. There is also detailed

agreement between the experimental data and bound state

structure factor calculations [7].

Despite its apparent simplicity, the spin-1/2 chain

features a potpourri of complex many body physics that

can be probed in exquisite detail using neutron spectroscopy. These experiments spur theoretical progress towards

understanding strongly correlated electron systems and

exemplify the close connection that is possible between

theory and experiment in low dimensional quantum

magnets.

References

[1] C. Broholm, et al., pp 211-234 in “High Magnetic Fields –

applications in condensed matter physics and spectroscopy” C.

Berthier, L. P. Lévy, and G. Martinez, Eds. Springer Verlag (2002).

[2] M. B. Stone et al., Phys. Rev. Lett., 91, 037205 (2003).

[3] M. Kenzelmann et al., cond-mat/0305476v1 submitted to Phys.

Rev. Lett. (2003).

[4] M. Karbach et al., Phys. Rev. B 66, 054405 (2002).

[5] D. Dender et al., Phys. Rev. Lett. 79, 1750 (1997).

[6] M. Oshikawa et al., Phys. Rev. Lett. 79, 2883 (1997).

[7] F. H. L. Essler et al., Phys. Rev. B 57, 10592 (1998).

0 0.5 1 0 0.5 1

q/π

(a) H = 0 T (b) H = 11 T

h (meV)

3

1

2

0
32

Spinels and pyrochlores are two of

 the most important crystal structures that are known to exhibit geometric

magnetic frustration. In these materials there are

three-dimensional networks of corner-sharing

tetrahedra, a structural arrangement that leads to a

high degree of magnetic frustration if the dominant

nearest-neighbor interactions are antiferromagnetic. One

interesting question that has not, to our knowledge, been

addressed experimentally concerns whether half-integral

spins exhibit fundamentally different behavior than integral

spins in frustrated lattices. In order to address this issue

we have been systematically investigating the magnetic and

structural properties of spinels in which integer or halfinteger-spin transition metal ions are located on the Bsublattice. In this report we describe the results [1] for an

integer-spin (S = 1) frustrated magnet GeNi2O4.

GeNi2O4 is a normal spinel with the Ni2+ ions on the

magnetically frustrated B-sites and the non-magnetic Ge4+

ions on the A-sites. GeNi2O4 becomes antiferromagnetic

below a Néel temperature of TN ≈ 12 K. The crystal

structure of GeNi2O4 has been refined, based upon neutron

powder diffraction data from BT-1, in the cubic space

group Fd3m at all temperatures. The structural refinements clearly demonstrate that there is no more than 1 %

cation inversion (interchange of Ge4+ and Ni2+ ions

between A and B sites), since Ge and Ni have very different neutron scattering lengths. This information cannot be

obtained from x-ray diffraction due to the similar x-ray

scattering strengths (atomic numbers) of Ge and Ni. In

addition, we have verified that GeNi2O4 remains cubic

below TN using very high-resolution synchrotron x-ray

powder diffraction at the Advanced Photon Source [1].

In Fig. 1 we show the crystal structure of GeNi2O4,

with the relative spin orientations of the Ni2+ ions illustrated

by plus and minus signs. The low temperature magnetic

structure is a simple two-sublattice collinear structure in

which the Ni2+ spins are aligned in ferromagnetic (111)

planes, and the spin direction of the (111) planes alternates

along the [111] direction [2]. Assuming this magnetic

structure, we obtain a good fit to the magnetic peak

intensities in our low temperature (T = 1.4 K) neutron

diffraction pattern.

Structure and Properties of the Integer

Spin Frustrated Antiferromagnet GeNi2O4

GeNi2O4 exhibits a surprising property, illustrated in

Fig. 2 where we plot the intensity of the magnetic (1⁄2,

1⁄2, 1⁄2) Bragg reflection as a function of temperature. The

Néel transition in GeNi2O4 clearly consists of two distinct

transitions, the first located at 12.13 K and the second at

11.46 K. Such double Néel transitions have been observed

in one-dimensional frustrated antiferromagnets [3], such

as the chain Haldane magnet CsNiCl3, but this is the first

observation, to our knowledge, of such a transition in a

three-dimensional frustrated magnet. The small splitting of

the Néel transition shows that the Ni2+ ions in GeNi2O4

have very little magnetic anisotropy, and should thus be in

the Heisenberg universality class.

The observation that GeNi2O4 remains cubic below

TN is in marked contrast with results for the transition

metal oxide spinel ZnCr2O4 [4]. ZnCr2O4 undergoes a

cubic-tetragonal structural phase transition at TN. Such

structural transitions have been described [5, 6] as threedimensional analogs of the spin-Peierls transitions that

occur in S = 1/2 one-dimensional antiferromagnets.

Fig. 1. A view of the crystal structure of GeNi2O4, illustrating the

magnetically frustrated corner-sharing tetrahedra. The relative Ni2+ spin

directions are shown by the plus and minus signs for the two collinear

magnetic sublattices.
Condensed Matter and Applied Physics

33

M. K. Crawford, R. L. Harlow, R. Flippen

DuPont Co., Wilmington, DE 19880-0356

P. L. Lee, Y. Zhang

Advanced Photon Source

Argonne National Laboratory, Argonne, IL 60439

J. Hormadaly

Ben Gurion University of the Negev

Beer Sheeva, Israel

Q. Huang, J. W. Lynn

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899-8562

R. Stevens, B. F. Woodfield, J. Boerio-Goates

Brigham Young University, Provo, UT 84602

R. A. Fisher

Lawrence Berkeley National Laboratory

University of California, Berkeley, CA 94720

Furthermore, we have observed [1] the appearance of

tetragonal distortions in two other spinels, GeCo2O4

(S = 3/2, effective spin 1/2 at low temperature) and

ZnFe2O4 (S = 5/2), each of which has half-integer-spin

transition metal ions. In both of these cases, the structural

transitions are also closely associated with TN, which

suggests that distortions from cubic lattice symmetry

generally occur at the Néel transitions in half-integer-spin

magnetically frustrated spinels.

In light of these observations for half-integer-spin

systems, it is interesting to speculate that the absence of a

structural transition in GeNi2O4 may be a consequence of

the integer-spin of the Ni2+ ion. In one-dimensional

antiferromagnets, spin-Peierls transitions for spin-1

magnetic ions are prevented by the appearance of Haldane

gaps, which render the chains rigid against dimerization

[7]. This raises the question of whether a related phenomenon can also exist in a three-dimensional integer-spin

frustrated lattice, which naturally leads us to measurements

of the spin excitations in the Néel state of GeNi2O4.

In Fig. 3 we show the low temperature heat capacity

of GeNi2O4. The data are superimposed with a fit including a contribution from gapless isotropic spin-waves and a

gapped excitation located approximately ∆ = 11 K above

the ground state. The gapped excitation in GeNi2O4 is a

property of the Néel state in the cubic structure, and thus

clearly requires a different explanation from the much

higher energy excitation reported in tetragonal ZnCr2O4

[4, 6]. The absence of a structural phase transition in

GeNi2O4 combined with the gapped magnetic excitation

spectrum strongly suggests a direct connection between

these phenomena and the integer spin of the Ni2+ ion.

Fig. 2. The intensity of the (1/2,1/2,1/2) magnetic Bragg reflection versus

temperature for GeNi2O4, measured on BT-7. The locations of the two

Néel transitions, TN1 and TN2, are shown.

Fig. 3. Low temperature heat capacity of GeNi2O4 (red circles). A fit to

the expression shown in the plot (blue line), assumes that both a gapless

spin-wave term (β3T 3), and a gapped magnetic excitation term

(BnT ne-∆/T, with n = 0 and ∆ = 11 K), are present. It should be noted that

the contribution to the T 3 term from the lattice (phonons) is about 8

times smaller than the magnetic contribution to this term at these low

temperatures.

References

[1] M. K. Crawford et al., Phys. Rev. Lett., submitted; M. K. Crawford

et al., unpublished results.

[2] E. F. Bertaut et al., J. Phys. 25, 516 (1964).

[3] M. F. Collins and O. A. Petrenko, Can. J. Phys. 75, 605 (1997).

[4] S.-H. Lee, C. Broholm, T. H. Kim, W. Ratcliff, and S.-W. Cheong,

Phys. Rev. Lett. 84, 3718 (2000).

[5] Y. Yamashita and K. Ueda, Phys. Rev. Lett. 85, 4960 (2000).

[6] O. Tchernyshyov, R. Moessner, and S. L. Sondhi, Phys. Rev. Lett.

88, 067203 (2002).

[7] F. D. M. Haldane, J. Appl. Phys. 57, 3359 (1985).

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

T (K)

0.00

0.05

0.10

0.15

0.20

C/T (J K-2 mol GNO-1)

GeNi2O4 [H = 0]

C = 3

T3 + BnTne- /T

(1⁄2, 1⁄2, 1⁄2)M Intensity (counts)7000

5000

3000

1000

10.0 11.0 12.0 13.0 14.0

T (K)

TN2

TN1

Warming

Cooling
34

Residual stresses have a major impact

 on the ability to fabricate dimensionally accurate machined components from

aluminum wrought mill products. In addition, the

ability to implement advanced assembly technologies such as determinant assembly, where parts are

indexed to each other rather than to expensive assembly

tooling, is compromised when the parts are not dimensionally accurate. An active research project on this

subject is underway in which NCNR scientists are collaborating with Alcoa and Boeing. The current status of this

project is outlined in this report.

In this work, finite element methods (FEM) are being

used to predict residual stress profiles and to examine the

influence of material processing and machining approaches

on part distortion. However, although Alcoa is developing

new destructive methods to estimate residual stresses in

bulk materials, the neutron diffraction capabilities of the

NCNR for characterizing residual stresses is key to

validating both the FEM calculations and the measurement

technique being developed at Alcoa. Ultimately, the goal is

to understand the generation of residual stresses and how

to control their effects in manufacturing and to correlate

model predictions with actual experimental measurements.

This information is critical in achieving optimization of the

Residual Stresses and Optimizing

Machining Strategies for Aluminum Bars

predictive capability utilizing new design tools that would

enable much more efficient manufacturing approaches than

are now employed.

The test system selected for the validation studies is a

long rectangular extruded bar in which the longitudinal

residual stress can vary as a function of position across the

width and through the thickness, i.e., σ = σ (x,y). The

material is aluminum alloy 2024 extruded using a 4-out die

pattern, producing bars with a 63.5 mm by 63.5 mm cross

section. For this study, four extrusions, each 1.83 m long,

were cut from the parent extrusion for thermal processing

at Alcoa and residual stress measurement and machining

trials at NIST. Three 0.61 m long sections were cut from

each extrusion. The twelve bars were attached in a vertical

orientation to a hanging rack at a heat treatment furnace.

All bars received a solution heat treatment (SHT) that is

typical for a 2024 alloy. At the end of the SHT soak time,

the material is quenched in 21 °C agitated tap water.

Because of the vertical hanging orientation, each bar should

experience the same quench on all four sides of the square

cross section.

Residual stress measurements were made over the

midplanes of three bars, randomly selected from the total,

using the BT-8 stress diffractometer at the NCNR. A 5 mm

by 5 mm by 5 mm sampling volume was used and the

Fig. 1. The measurement configuration on the BT-8 instrument at the

NCNR for residual stress determinations on three 2024 Al bars. Neutrons

issuing from the collimated beam tube on the left are collected from the

sample volume by the detector on the right. The sample is scanned by

moving the mounting table.

Fig. 2. The effect of microstresses is minimized by utilizing 36 d0

samples in which macrostresses are relaxed by the cross-cutting

technique shown.
Condensed Matter and Applied Physics

35

T. Gnäupel-Herold

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899-8562

 and

University of Maryland

College Park, MD 20742

H. Prask

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899-8562

R. Fields

Metallurgy Division

National Institute of Standards and Technology

Gaithersburg, MD 20899-8553

D. Bowden

Boeing Co.

St. Louis, MO 63166

E. Chu, M. Newborn, and R. Schultz

Alcoa, Inc.

Alcoa Center, PA 15069

Fig. 3. Comparison of measured to calculated residual stresses.

σii > 0 is tensile; σii < 0 is compressive. The upper panels represent the

measurements while the lower panels show the comparable computed

stresses.

measurements made over a 9 x 9 mesh, 7.06 mm between

centers. Because the material was composed of relatively

large grains, the data were obtained by longitudinally

averaging over a 90 mm long volume, extending ± 45 mm

from the mid-plane. Since FCC metals are susceptible to

grain-grain interaction microstresses, samples to provide

the unstrained d spacing, d0, representative of the whole

cross-section were needed. These were obtained from a

25.4 mm by 63.5 mm by 63.5 mm piece cut from the end

of a bar, and partially cut through the thickness in a 10 mm

by 10 mm by 10 mm (6 x 6 mesh) pattern. The instrument and samples are shown in Figs. 1 and 2. Residual

stresses were obtained from the measured d-spacings

according to methods described previously [1].

The FEM is used to model the material and processing in order to guide the design of machining processes for

optimal results. The initial objective of the FEM modeling is

to obtain values for the level of quench-induced stress and

to develop a simple final part geometry that exhibits widely

varying distortion behavior as a function of machined part

location. This involves a quenching simulation that predicts

the thermal response of the aluminum to the quenchant, a

mechanical simulation that predicts the quench-induced

stress state and, finally, a machining simulation to predict

the distortion. It is noted that the entire modeling process

for identifying a machined part involves many FEM

simulations and it is critical to have an efficient process for

making changes to the input geometry and final part

location [2].

In the upper part of Fig. 3 the three normal residual

stress components determined by neutron diffraction are

shown for one of the three bars studied. The distributions

for the three bars were in reasonable agreement, but not

identical — even within uncertainties. The lower part of

Fig. 3 shows the FEM results for a bar.

The results, thus far, are encouraging although the

minimum and maximum FEM-predicted residual stresses

are somewhat too compressive for the xx and yy components. However, the real test of this project is in progress:

that is, the capability to predict by a “machining” FE model

the machined part distortion for a final part geometry and

location chosen by the user utilizing the residual stress

distribution previously calculated from the mechanical

simulation. “L” shaped pieces will be machined from

different positions in the three characterized bars. The

FEM calculations predict significant differences in the

amount of part distortion depending on the location of the

“L” within the 63.5 mm by 63.5 mm cross section. The

results are expected to be significant for a number of major

applications.

References

[1] H. J. Prask and P. C. Brand, in Neutrons in Research and Industry,

ed: G. Vourvopoulos, SPIE Proceedings Series, Vol. 2867, pp. 106-

115 (1997), and references cited.

[2] M. A. Newborn and R. W. Schultz, The Influence of Residual Stress

in Quenched 2024 Bar Stock on Machining Distortion, Alcoa Inc.

internal publication, 2003.

Stresses (in MPa) measured by neutron diffraction: 

min (blue) to max (brown)

 xx (-157 ± 8 to 97 ± 8) yy (-175 ± 7 to 104 ± 9) zz (-211 ± 6 to 245 ± 8)

Stresses (in MPa) calculated by finite-element method: 

min (blue) to max (red)

xx (-223 to 78) yy (-223 to 78) zz (-234 to 227)
36

Multicriticality in the

Bragg-Glass Transition

Fig. 1. (a) Temperature and history dependence of azimuthal widths of

the (1,-1) diffraction peak at H = 0.3 T. The dashed line is the peak effect

Tp at this magnetic field based on ac magnetic susceptibility measurements. Inset: experimental configuration. (b) Widths at H = 0.2 T. The

ac susceptibility data are also shown for reference. Definitions of Tp(H )

and Tc3(H ) are shown.

The discovery [1] of a first-order

 solid-liquid transition in the vortex

matter of a classic type-II superconductor

niobium was widely regarded as an important

result since it resolved a long-standing issue of

whether a genuine order-disorder transition can take

place in the vortex system in type-II superconductors,

and whether the anomalous peak effect is indeed caused

by a structural phase transition in the vortex matter.

However, in a follow-up SANS experiment [2] on a Nb

crystal which has a lower upper critical field, suggesting

even less bulk disorder, neither the first-order transition nor

the peak effect was found. These two seemingly contradictory results suggest either a trivial technical error in one

of the two experiments, or something more profound and

interesting in the physics of vortex matter, namely the

existence of multicritical behavior in the Bragg-glass

transition. We have now carried out a systematic study of

the Nb crystal used in our original experiment, and have

found such a multicritical point [3].

Our experiment was carried out on a Nb single

crystal in which both the peak effect and the first-order

Bragg-glass melting transition were observed at the same

temperatures [1]. The sample has a zero-field Tc = 9.16 K,

and an estimated Ginzburg-Landau parameter κ(0) = 2.0.

The experimental SANS configuration is shown in the inset

of Fig.1 (a). The dc magnetic field was applied in the

direction of the incoming neutron beam using a horizontal

superconducting magnet. A coil was wound on the sample

to allow in situ ac magnetic susceptibility measurements.

Fig.1(a) shows the SANS data at H = 0.3 T. The

Gaussian widths are obtained from fitting the Bragg peaks

(in intensity vs. azimuthal angle) to six Gaussian peaks

evenly spaced 60° apart. It is clear that the azimuthal

widths — a measure of orientational disorder in the vortex

array — are strongly history dependent. Supercooling and

superheating effects are observed for field-cooling (FC)

and field-cooled-warming (FCW) paths, respectively. As

reported previously [1], the disordered phase at T > Tp

and the ordered phase at T < Tp are their respective

thermodynamic ground states. The abrupt change in the

structure factor S(q) at the peak effect Tp depicts a

symmetry-breaking phase transition from a vortex liquid

with short-range order to a Bragg glass with quasi-long

range order [1]. The phase transition is first order as

evidenced by the strong thermal hysteresis in S(q). Compared to that at higher fields, the metastability region for

H = 0.3 T is smaller but still pronounced.

It was found that the thermal hysteresis of S(q)

observed in SANS is strongly field dependent, and the

metastability region disappears completely at low fields.

(a) H = 0.3 T isotropic limit

FCW

FC

cold neutron beam

to lock-in

sample

SANS

detector

H

30

25

20

15

10

5

3

0

3.5 4 4.5 5 5.5 6

T (K)

Tc3 (H)

(b) H = 0.2 T

∆ (deg.)

30

25

20

15

10

5

0

345 6 789

T (K)

Tp (H)

0

-0.5

4π '

0 ∆ (deg.)

0
Condensed Matter and Applied Physics

37

S. R. Park and X. S. Ling

Brown University

Providence, RI 02912

S.-M. Choi

Korea Advanced Institute of Science and Technology

Taejon

South Korea

D. C. Dender and J. W. Lynn

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899

Fig. 2. Three-dimensional (3D) magnetic field and temperature

dependence of the real part of the ac susceptibility 4πχ ′(T ). Note that

two values of ac fields were used in the measurements. For H < 0.3 T,

Hac = 0.17 mT, and for H > 0.3 T, Hac = 0.7 mT, f = 1.0 kHz. The solid and

dashed lines are guides to eyes. For the ac fields used, Tp is independent

of the ac field amplitude.

Fig. 1 (b) shows the azimuthal width data for H = 0.2 T.

For comparison, the real part χ ′(T) of the ac magnetic

susceptibility is also shown in Fig.1(b). The dip in χ ′(T) is

the well-established signature of the peak effect [1]. The

history dependence of the Bragg-peak width is only

detectable within 100 mK of the peak-effect temperature

Tp.

 A similar trend is observable in the history dependence

of the radial widths of the Bragg peaks. At 0.3 T, there is a

pronounced thermal hysteresis in the radial widths. At

0.2 T, however, the hysteresis is barely discernable. At an

even lower field of 0.1 T (data not shown), the thermal

hysteresis in S(q) is undetectable.

At H = 0.1 T, a very sharp peak effect (the onset-toend width = 40 mK) is still present. Thus we believe the

phase transition at 0.1 T is still first-order but the metastability region is too narrow to be resolved in SANS (the

temperature resolution was ≈ 50 mK). Nevertheless, the

diminishing hysteresis in the low-field regime suggests that

the phase transition is becoming continuous and meanfield-like, namely there is a multicritical point on the phase

boundary bordering the Bragg glass on the H-T phase

diagram. We show that this multicritical behavior is directly

related to the appearance and the disappearance of the peak

effect.

Fig. 2 shows a three-dimensional plot of the χ ′(T) as

a function of temperature and magnetic field. At high

fields, there is a pronounced peak effect, a characteristic

dip in χ ′(T). At higher temperatures above the peak-effect

temperature Tp(H) (or Hp(T), used interchangeably), there

is a smooth step in χ ′(T). This step, Tc3(H) (or Hc3(T)),

defined in Fig.1 (b), is the onset of surface superconductivity. In the mean-field theory of Saint-James and de

Gennes, Tc3(H) is a continuous phase transition. The

separation between Tp(H) and Tc3(H) grows larger with

increasing magnetic field. Upon cooling, below Tc3(H) and

toward Tp(H), the screening effect in χ ′(T) increases

gradually but there is no sharp feature to define another

temperature scale. With decreasing field, the peak effect

becomes narrower and smaller. For H < 0.08 T, there is

only a single kink in χ ′(T) corresponding to the mean-field

transition Tc2(H) or Hc2(T). There is no reentrant peak

effect at low fields — the peak effect simply vanishes

here. New theoretical studies are needed to elucidate the

possible physical mechanisms of the multicritical point in a

Bragg glass.

References

[1] X. S. Ling, S. R. Park, B. A. McClain, S. M. Choi, D. C. Dender, and

J. W. Lynn, Phys. Rev. Lett. 86, 712 (2001).

[2] E. M. Forgan, S. J. Levett, P. G. Kealey, R. Cubitt, C. D. Dewhurst,

and D. Fort, Phys. Rev. Lett. 88, 167003 (2002).

[3] S. R. Park, S.-M. Choi, D. C. Dender, J. W. Lynn, and X. S. Ling,

submitted to Phys. Rev. Lett. (cond-mat-0305569).

Hc3

Hc2

Hp

0

-0.2

-0.4

-0.6

-0.8

-1

0.4

0.3

0.2

0.1

0 2

4

6

8

10

H (T) T (K)

4π '
38

The transition metal oxides have been

 the source of many fascinating

physical phenomena such as high Tc superconductivity, colossal magnetoresistance, and

orbiton physics [1]. These surprising and diverse

physical properties arise from strong correlation

effects in the 3d bands. Most theoretical attempts to

understand such systems are based on the Hubbard

model. Here we report that for high symmetry transition

metal oxides with threefold t2g bands, this model possesses

several novel hidden symmetries with many surprising

consequences on the ground state properties [2, 3].

We consider cubic 3d1 perovskites (i.e., ABO3)

where the five initially degenerate 3d states are split into a

two-fold eg manifold and a lower-energy threefold t2g

manifold with wavefunctions dyz ≡ X, dxz ≡ Y, and dxy ≡ Z

(see Fig. 1). Keeping only the t2g states, we base our

discussion on the following generic three-band Hubbard

Hamiltonian:

Hidden Symmetries and Their

Consequences in the t2g Cubic Perovskites

Fig. 1. A schematic view of the splitting of the five-fold 3d orbitals

under cubic crystal field. The transition metal is located at the center of

the oxygen octahedra (shown in blue).

Fig. 2. A schematic view of the symmetry of the hopping parameter t via

intermediate oxygen p-orbitals. Note that there is no hopping between

different d-orbitals and no hopping along the z-axis for Z-orbitals due to

symmetry.

z

y

x

t = 0

t ≠ 0

t = 0

Here ci,α,σ creates a t2g electron (or hole) on the ith

ion in the α spatial orbital (i.e., α = X, Y or Z) with spin σ,

and εi,α is the on-site energy of the orbital at site i of a

simple cubic lattice. Uiα,iβ is the on-site Coulomb repulsion

between orbitals α and β at site i. t

iα, jβ

 is the effective

hopping parameter from the α orbital at site i to the β

orbital at its nearest neighbour site j.

As shown in Fig. 2, for cubic perovskites where the

metal-oxygen-metal (M-O-M) bond is linear, the hopping

parameter t

iα, jβ is diagonal in the orbital indices α and β.

This suggests that the total number of electrons in each

orbital is a good quantum number. Furthermore t

iα, jβ is

zero along the “inactive” axis perpendicular to the orbital

plane α, due to symmetry (Fig. 2). In other words an

α-electron can only hop in α-plane. Thus, for the nth plane

perpendicular to the α-axis, the total number Nnα

 of

electrons in the α-orbital is conserved, i.e., it is a good

quantum number. Hence, one can consider the three

dimensional lattice as a superposition of interpenetrating

planes perpendicular to the x, y, and z-directions, each

having a constant number of X, Y, and Z electrons,

respectively, which are good quantum numbers (see

Fig. 3(a)).

+

z

z

x

x

y

y

dxy = Z

dxz = Y dyz = X

Cubic

crystal field

t

2g

eg

3d1
Condensed Matter and Applied Physics

39

T. Yildirim

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899

A. B. Harris

University of Pennsylvania

Philadelphia, PA 19104

A. Aharony, O. Entin-Wohlman, and I. Ya. Korenblit

Tel Aviv University

Tel Aviv 69978, Israel

In Ref. [3] we also show that the global rotation of

the spins of α-orbital electrons in any given plane perpendicular to the α-axis leaves the Hubbard Hamiltonian given

in Eq. (1) invariant. As a consequence of this rotational

symmetry, one may conclude that both the Hubbard model

and its 2nd order perturbation at order of t2/U, the KugelKhomskii (KK) Hamiltonian, cannot support any long range

spin order: if one assumes long-range spin order, the spins

associated with α-orbitals within any given plane can be

rotated at zero cost in energy, thereby destroying the

supposed correlations among planes and/or among orbitals,

and therefore the long-range order [2, 3]. The crucial

conclusion here is that any credible theory of spin-ordering

in these systems cannot be based solely on the KK Hamiltonian, as currently done in the literature.

The hidden symmetries discussed here are very

useful in simplifying the exact numerical studies of small

clusters. For example, to treat the simpler KK Hamiltonian

for a cube of eight sites even using the conservation of the

total spin (a widely used symmetry) requires the diagonalization of a matrix of dimensionality on the order of

1⁄2 million. Using the conservation laws applied to each face

of the cube (see Fig. 3(a)), there is an astonishing numeriFig. 3. (a) Six conserved quantum numbers as identified in the text,

(b)-(c) Spin and orbital configurations for a cube of eight sites,

indicating singlet spin dimers (as shown by thick blue lines) along the

x-axis for Y-electrons and along y-axis for X-electrons. Configurations in

(b) and (c) are the dominant ones in the ground state wavefunction. The

less dominant configuration (d) is obtained from (c) by allowing the

interchange of two x- and y- electrons along the z-axis, retaining their

membership in the spin singlets.

cal simplification. The ground state can be found from a

Hamiltonian matrix within a manifold of just 16 states!! As

seen in Fig. 3(b-d), these states are all products of four

dimer states in each of which two electrons are paired into

a spin zero singlet state. In this model a very unusual

phenomenon occurs: when the electrons hop from site to

site along active axes, they retain their membership in the

singlet they started in. An example of this transformation

is seen by comparing Figs. 3(c) and 3(d): pairs of electrons are tied together, as if by quantum mechanical rubber

bands!

In conclusion, we uncovered several novel symmetries of the Hubbard model for orthogonal t2g systems.

Using these symmetries, we rigorously showed that both

the original Hubbard Hamiltonian [2] and the KK effective

Hamiltonian [1] (without spin-orbit interactions) do not

permit the development of long-range spin order in a three

dimensional orthogonal lattice at nonzero temperature. It is

important to take proper account of the symmetries

identified here and to recognize that the observed longrange spin order can only be explained with the Hubbard or

KK Hamiltonian providing suitable symmetry breaking

terms are included. Such perturbations therefore play a

crucial role in determining the observed behavior of these

transition metal oxides. We hope that these results will

inspire experimentalists to synthesize new t2g transition

metal oxides with tetragonal or higher symmetry. Such

systems would have quite striking and anomalous properties.

References

[1] Y. Tokura and N. Nagaosa, Science 288, 462 (2000) and references

therein.

[2] A. B. Harris, T. Yildirim, A. Aharony, O. Entin-Wohlman, and I. Ya.

Korenblit, Phys. Rev. Lett. (in press, 2003)(cond-mat/0303219).

[3] A. B. Harris, T. Yildirim, O. Entin-Wohlman, and A. Aharony, Phys.

Rev. B (cond-mat/0307515).

(a) (b)

(c) (d)

z

y

x

n2z

n1x

n2y

n1z

n1y

n2x
Acrylonitrile is not a household word,

 but products made from it are

ubiquitous in our homes. Acrylic fibers made

from acrylonitrile are used to make our clothing

and carpets; they even reinforce paper products.

Acrylonitrile-based plastics are often impact resistant

and are used for computer and video-cassette cases. It

is also formulated into nitrile rubber products, which are

impervious to most solvents and thus are products of

choice to contain gasoline or as protective gloves for lab

use.

Worldwide, approximately 10 billion pounds of

acrylonitrile are made each year through the reaction of

ammonia and propylene. However, there is considerable

interest in production of acrylonitrile from the reaction of

ammonia and propane, since the latter compound is cheap

enough to burn. Several multi-component mixtures have

been tried as potential catalysts for this reaction, known as

propane ammoxidation. The best of these mixtures

contains molybdenum oxides doped with various transition

metals. Neither the chemical structures nor the mechanism

of operation of the various phases in the catalyst was

previously understood.

Structural Characterization

of Acrylonitrile Catalysts

In 2001, workers at CNRS and Elf Atochem, both in

France, used electron microscopy to study the most

effective known propane ammoxidation catalyst, a (Mo, V,

Nb, Te) oxide, and determined that it was composed of

two chemical phases, an orthorhombic phase, labeled M1

and a hexagonal phase, known as M2. [1] They were even

able to propose schematic structures for these materials.

These models, however, do not indicate which cation is

found at a particular site and thus provide no knowledge of

cation coordination or valence state. Thus, these schematic

structures provide little insight into the catalysis function of

the materials.

The M1 and M2 compounds are not simple phases.

They have large unit cells and do not form single crystals.

Therefore, detailed structural information can come only

from powder diffraction studies. However, materials of

this form, with 40+ atoms in the asymmetric unit are at the

limit of where powder diffraction can be used to resolve

individual atoms. Further, deviations from crystallinity are

seen readily in the electron microscope. The presence of

these “errors” in crystallization reduces the long-range

ordering in the material and degrades the diffraction

pattern, which reduces the amount of structural information that can be obtained. Structural analysis from a

mixture of the M1 and M2 phases is not possible. With the

advent of combinatorial synthesis, collaborators at Symyx

Technologies, Inc. were able to find ways to synthesize the

M1 and M2 phases separately. [2] With reasonably pure

phases it becomes possible to consider structure determination to learn how the materials function. With those

questions answered, there is hope to create even better

catalysts, that will further improve the industrial production

of acrylonitrile from the desired starting materials.

The usefulness of x-ray diffraction for structure

elucidation for these phases is also limited, because the

scattering from O is almost negligible in the presence of

heavy elements such as Mo, Nb and Te. For that matter,

Mo and Nb are virtually indistinguishable with x-rays. With

neutron powder diffraction, however, O scattering is

comparable to the other atom types and Mo and Nb can

potentially be distinguished. However at natural abundance,

V is invisible to neutron diffraction.

Due to the complexity of these structures, even with

neutron and x-ray powder diffraction data combined, it

Fig. 1. A view of four unit cells of the M1 propane ammoxidation

catalyst viewed along the c-axis. O atoms are shown as brown spheres

and polyhedra are color coded by cation type: Mo6+ = purple,

Mo5+ = pink, Mo6+/ Mo5+ = light blue, Mo6+/ V5+ = red, Mo5+/V4+ = green,

Te4+ = yellow. The regions believed to be active sites for catalysis are

shown in rectangular boxes [3].

40
Condensed Matter and Applied Physics

P. DeSanto Jr., D. J. Buttrey and R. K. Grasselli

University of Delaware

Newark, DE 19716

C. G. Lugmair and A. F. Volpe Jr.

Symyx Technologies, Inc.

Santa Clara, CA 95051

B. H. Toby

NIST Center for Neutron Research

National Institute of Standards and Technology

Gaithersburg, MD 20899-8562

 and

T. Vogt

Brookhaven National Laboratory

Upton, NY 11973

would still be very difficult and perhaps impossible to

determine the structures ab initio. However, using unit cell

dimensions and schematic models from electron microscopy, it was possible to build and test atomistic models

against the neutron and x-ray powder diffraction data sets

individually and in final stages, the two data sets combined.

Using this approach, the structure of the M1 phase was

determined (see Fig. 1). Work on the structure of the M2

phase, which turns out to be also orthorhombic, is nearly

complete.

The result for the M1 phase shows that the material

has a layer structure with two sets of channels, one

approximately hexagonal, the other roughly heptagonal.

The channels allow for the accommodation of large metal

cations. This is where the large Te4+ cation atom sits. The

large channel provides access to the cation’s lone pair

electrons, which is likely quite important in the

ammoxidation reaction. Structural results also provide

details of the metal atom coordination, which can then be

used to determine the most likely oxidation state for each

atom, as is indicated in the figure. Based on these structural results, it becomes possible to explore how the

catalyst functions, as is outlined in Fig. 2 [3]. The active

sites for propane oxidation to propylene are most likely the

bridging lattice oxygen between V5+ cations and neighboring V4+ or Mo5+. The subsequent addition of ammonia then

occurs at a Mo6+ cation that neighbors the sites where

propane is converted to propylene. Presumably, abstracFig. 2. A schematic mechanism for propane ammoxidation by the M1 catalyst that details the

cation centers believed to be responsible for reactive process [3].

tion of hydrogen is carried out at Te4+

centers. The chemical function of the M2

phase will be more clear when the structure

of that material is fully determined. However, it is clear that the M2 phase plays a

role in the conversion of incompletely

reacted intermediates that desorb from the

M1 catalyst prior to the completion of the

propane ammoxidation reaction.

Predicted oxidation states of V and

Mo in M1 from the refined structure are

consistent with those observed in XPS and

EPR studies. The Te environment is

consistent with those observed by Millet et

al. using EXAFS in mixed-phase samples

[4].

Only with the combination of numerous techniques was it possible to solve this

propane ammoxidation catalyst puzzle.

Neutron powder diffraction was essential

for refinement of metal and oxygen coordinates and determination of metal-oxygen bond lengths,

which was pivotal to calculating cation oxidation states and

characterizing the chemical nature of the surrounding

oxygen atoms.

References

[1] M. Aouine, J. L. Dubois, and J. M. M. Millet, Chem. Commun. 13,

1180 (2001).

[2] P. DeSanto Jr, D. J. Buttrey, R. K. Grasselli, C. G. Lugmair, A. F.

Volpe Jr., B. H. Toby and T. Vogt, Topics in Catalysis, 23 (1-4),

23-38 (2003).

[3] R. K. Grasselli, J. D. Burrington, D. J. Buttrey, P. DeSanto Jr, C. G.

Lugmair, A. F. Volpe Jr., and T. Weingand, Topics in Catalysis, 23

(1-4), 5-22 (2003).

[4] J. M. M. Millet, H. Roussel, A. Pigamo, J. L. Dubois, and J. C.

Jumas, App. Cat. A: Gen. 232 (1-2), 77 (2002).

H

H2O

Te3+

O

HO

Te3+

O

HO

Te4+

O

O

O

Mo6+

V 5+

O

O O

O

Nb5+

Mo6+

O

NH

O O

O O

O

O

O O

Te4+

O

O

Te4+

O

O

O

Mo6+

V4+

O

O O

OH

Nb5+

Mo6+

O

NH

O

O

O O

O

O

O O Te3+

O

OH

O

Mo6+

V 4+

O

O O

OH

Nb5+

Mo6+

O

NH

O

O

O O

O

O

O O Te4+

O

O O

Mo6+

V 4+

O

O

O

OH

Nb5+

Mo6+

O

NH

O O

O O

O

O

O O Te3+

O

OH

Te4+

O

Te O 3+

O

OH

Te4+

O

O

O

Mo6+

V4+

O

O O

HO

Nb5+

Mo6+

O

NH

O

O

O O

O

O

O

H

O

H

O2

1/4 O2

1/2 O2

1/2 H2O

1/4 O2

1/2 H2O

N

NH3

H2O O

O

Mo6+

V+4

O

O

O

OH

Nb5+

Mo4+

O

NH

O

O

O

O

O

O

O

Mo6+

V 5+

O

O

O

O

Nb5+

Mo6+

O

NH

O

O

O O

O

O

O O

O

Mo6+

V 4+

O

O

O

OH

Nb5+

Mo5+

O

O

O

O O

O

O

O

H

H

N

O

N

H

O

Mo5+

V 4+

O

O O

OH

Nb5+

Mo5+

O

O O

O O

O

O

HO O

N

H

O

Mo6+

V 4+

O

O

O

OH

Nb5+

Mo5+

O

O

O

O O

O

O

O O

O

Mo 6+

V 4+

O

O

O

OH

Nb5+

Mo4+

O

O

O O

O O

O

O

O

H2O

.

.

41
42

Serving the Science

and Technology Community

The past year has been perhaps the

 best ever for users at the NCNR, in

terms of numbers of participants, and the

diversity and quality of their research activities at

our facility. Nearly all of the originally envisioned

instruments have been operational for several years,

and forefront science, as represented by the highlight

articles in this report, is being produced at a steady rate.

Although it is fair to say that the NCNR has reached a

mature state of development, new instruments are still

being developed and brought on line. The CNBT reflectometer (AND/R) is being completed during the summer of

2003, and the MACS cold-neutron triple-axis and an

upgraded 10 m SANS diffractometer will be made available

in the near future.

The User Program

Making the NCNR accessible to a diverse community

from academia, government and industry requires continual effort. Efficient proposal handling, fair and thorough

review, and timely allocation of instrument time are essential to our user community. For the past year, our

proposal process, including proposal review as well as

submission, has been entirely Internet-based, resulting in a

significant shortening in the time between proposal deadline

and beamtime allocation. Despite increased security,

physical access to our facility has been significantly

delayed in only a handful of cases. User demand has

remained very strong, with research participation (see

Fig. 1) and the number and quality of proposals at an alltime high.

While there are several ways in which users access

NCNR instrumentation, the most important is through our

formal proposal process. At approximately six-month

intervals, users may submit proposals for beam time. After

each proposal has received written reviews from external

referees, our Program Advisory Committee (PAC) allocates

beam time to the best proposals, based on the reviews,

their own judgment, and technical input from NCNR staff.

Current PAC members include Andrew Allen (NIST

Ceramics Division), Robert Briber (Maryland), Michael

Crawford (DuPont), Sossina Haile (Cal Tech), Kenneth

Herwig (Oak Ridge), Yumi Ijiri (Oberlin), Michael Kent

(Sandia), Sanat Kumar (Rensselaer), Robert Leheny (Johns

Hopkins), Dieter Schneider (Brookhaven), and John

Tranquada (Brookhaven). Over the course of a year, the

PAC allocated more than 1100 instrument-days to more

than 290 experiments. In doing so, it had to make some

difficult choices, since a total of more than 2400 days

were requested in more than 380 proposals. The proposal

system applies to only about half the instruments at the

NCNR, but these are our most advanced ones, supported

at a high level by NCNR staff and all our available resources. Although the other instruments are not offered

through proposals, most of the time on the latter is also

allocated to users through direct collaborations with local

staff, or through more formal collaborative research

consortia, as detailed below. For example, short- and

long-term collaborations account for most of the beam

time scheduled on the thermal triple-axis spectrometers.

A New Voice for Users

A separate advisory committee has recently been

formed to represent our user community. At monthly

conference call meetings, members of the NCNR Users’

Committee discuss users issues, sometimes with the Fig.1. Numbers of NCNR Research Participants over time.

0

500

1000

1500

2000

2500

3000

86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03

Year

NCNR Research Participants

1st Cold Source Upgrade

In 2003 Research Participants were from

 19 NIST Divisions and Offices

 31 U.S. Government Laboratories

131 U.S. Universities

 41 U.S. Corporations
43

Serving the Science and Technology Community

participation of NCNR staff and management. The current

membership includes Nitash Balsara (UC Berkeley, chair),

Collin Broholm (Johns Hopkins), Paul Butler (Oak Ridge),

Tonya Kuhl (UC Davis), Robert Leheny (Johns Hopkins)

(liaison to the PAC), and Paul Sokol (Penn State). Among

recent topics of discussion were software for data analysis, sample environments, the proposal process, and

obtaining feedback from users. The committee welcomes

comments from users at any time. Please see http://

www.ncnr.nist.gov/NCNR_Users_Commitee.html for the

members’ email addresses.

Center for High Resolution Neutron

Scattering

The Center (CHRNS) is a most important component

of user participation at our facility. Funded by the National

Science Foundation (NSF) and NIST, it offers a suite of

instruments unmatched in North America for the investigation of the structure and dynamics of solids by neutron

scattering, probing length scales from 1 nm to ≈ 10 μm

and energies from ≈ 30 neV to ≈ 100 meV. Most of the

proposals we receive ask for time on one of the CHRNS

instruments, which include two 30 m SANS diffractometers, a high-resolution USANS diffractometer, a backscattering spectrometer, a neutron spin echo spectrometer,

and a cold-neutron triple-axis spectrometer. An upgraded

10 m SANS diffractometer will be included among the

CHRNS instruments in the near future.

Cold Neutrons for Biology and

Technology

A new instrument for structural biology, the Advanced Neutron Diffractometer/Reflectometer, AND/R, has

recently been completed. (See highlight on page 6 of this

report.) This instrument and other facilities dedicated to

studies of biological membrane systems are part of the

Cold Neutrons for Biology and Technology (CNBT)

program, funded by the National Institutes of Health

(NIH), with contributions from NIST, the University of

California at Irvine and the University of Pennsylvania. In

addition to the above-mentioned institutions, the CNBT

partnership consists of investigators from Johns Hopkins

University, Rice, Carnegie Mellon, and Duke University.

Other collaborators are from UC San Diego, the Los

Alamos National Laboratory, and NIH. Other facilities at

NCNR dedicated to CNBT include 10 % of the time on the

NG-7 30 m SANS diffractometer, a fully equipped biology

laboratory, and a state of the art computer facility for

molecular dynamics computations. The combination

provides a powerful set of capabilities for U.S. researchers

interested in structural biology investigations by neutron

scattering.

NOBUGS 2002

A conference on scientific computing at user facilities

was hosted by NIST on November 4–6, 2002, addressing

both software and hardware issues at neutron and synchrotron x-ray user facilities. The 77 participants represented nearly all the world’s major scattering laboratories.

The 2002 conference, organized by NCNR staff, was the

fourth in the biennial NOBUGS series, providing an

opportunity for those involved to compare notes, discuss

techniques and results, and establish collaborations in the

area of computing and data acquisition infrastructure for

research, a field not normally covered by traditional

scientific conferences. Among the topics highlighted at

NOBUGS 2002 were Data Acquisition and Instrument

Control Methods, Data Formats, Data Reduction, Visualization and Analysis, Collaborative Initiatives and Distributed

Computing, and Computer Security at User Facilities.

Ninth Annual Summer School

More than 30 students from 23 different institutions

traveled to the Gaithersburg, MD campus of the National

Institute of Standards and Technology to attend the ninth

annual summer school on neutron scattering during the

week of June 9–13, 2003. The school was organized by

the NCNR and CHRNS with support from the National

Science Foundation, and involved students from 18 states

and Canada with diverse backgrounds ranging from

chemistry, physics, and materials science, to polymer

science, nuclear engineering, and biophysics. The summer

school alternates every year between the two central

themes of diffraction and spectroscopy. This year’s

school focused on four different dynamical studies using

the NCNR’s Disk Chopper Spectrometer (DCS), High-Flux

Backscattering Spectrometer (HFBS), Neutron Spin Echo

(NSE) spectrometer, and Spin Polarized Inelastic Neutron

Scattering (SPINS) spectrometer. Most of the students’

efforts were directed to hands-on experiments, a direction

that we have followed for several years. Course materials

about the experiments and underlying principles were

made available through our website prior to the school.

Small groups of students rotated among the instruments, performing illustrative experiments, and

analyzing their data with the aid of our

software and the advice of our staff.

Among the experiments was the study

of the diffusion of surfactant

micelles and shape fluctuations of
44

microemulsions

using the NSE spectrometer, and quantum

rotations in methyl iodide using

the HFBS. On the final day, each of

the student groups presented the results

of their studies to the rest of the school.

According to evaluations, the school was

highly effective in introducing the students to the

various methods and applications of neutron

spectroscopy.

Theory, Modeling, and Neutron

Scattering

Modern materials research relies heavily on developing models that explain and predict behavior under a variety

of conditions. Because of the relatively simple nature of

the interaction between neutrons and materials and the

wide dynamical and spatial ranges that can be probed,

neutron scattering is an important method for testing the

validity of these theoretical models. To promote a fruitful

exchange between theory and experiment, NCNR’s Taner

Yildirim, Seung-Hun Lee and Dan Neumann organized a

workshop entitled Theory, Modeling and Neutron Scattering co-sponsored by the NCNR and NIST Center for

Theoretical and Computational Materials Science. This

workshop brought experts from around the world on both

theoretical and modeling methods and neutron scattering

measurements to the NCNR for a three-day meeting in

August 2003. Invited presentations covering a wide range

of materials from proteins to nanotubes to magnetic

perovskites sparked an intense discussion among the more

than 50 attendees on how combining these techniques

offers key insights into a remarkable variety of phenomena

in materials.

Independent Programs

The Neutron Interactions and Dosimetry Group

(Physics Laboratory) provides measurement services,

standards, and fundamental research in support of NIST’s

mission as it relates to neutron technology and neutron

physics. The national and industrial interests served

include homeland defense, neutron imaging, scientific

instrument calibration, nuclear-electric power production,

radiation protection, defense nuclear energy systems,

radiation therapy, and magnetic resonance imaging. The

group’s research may be represented as three major

activities. The first is Fundamental Neutron Physics

including magnetic trapping of ultracold neutrons, operation of a neutron interferometry and optics facility, development of neutron spin filters based on laser polarization of

3

He, measurement of the beta decay lifetime of the neutron,

Fig. 2. Daniel Phelan, Souleymane Omar Diallo, Hui Wu and Seth Jonas analyze results of a backscattering spectrometry experiment at the ninth

annual Summer School on Neutron Scattering.
45

Serving the Science and Technology Community

and investigations of other coupling constants and symmetries of the weak interaction. This project involves a large

number of collaborators from universities and national

laboratories. The second is Standard Neutron Fields and

Applications using both thermal and fast neutron fields for

materials dosimetry in nuclear reactor applications, neutron

spectrometry development, and for personnel dosimetry in

radiation protection. These neutron fields include thermal

neutron beams, “white” and monochromatic cold neutron

beams, a thermal-neutron-induced 235U fission neutron

field, and 252Cf fission neutron fields, both moderated and

unmoderated. The third is Neutron Cross Section Standards, including experimental advancement of the accuracy

of such standards, as well as their evaluation, compilation

and dissemination.

The Smithsonian Center for Materials Research

and Education’s (SCMRE) Nuclear Laboratory for

Archeological Research has chemically analyzed over

26,600 artifacts by INAA at the NCNR over the last 26

years. SCMRE’s research programs draw extensively upon

the collections of the Smithsonian, as well as those of

national and international institutions. The chemical

analyses provide a means of linking these diverse collections together to study continuity and change involved in

the production of ceramic objects. INAA data are used to

determine if groups of ceramics have been made from the

same or different raw materials. The ceramics can then be

attributed to geographic regions, specific sources, workshops and even individual artists. The ability to use chemical composition to link specific pottery groups to specific

production locations through the analysis of less portable

fired tiles and bricks has shown that nearly all individual

California missions were producing earthenware ceramics

for their own use soon after their founding. Moreover,

potters at five missions had mastered the technologically

demanding process of glazing and were also producing Pb

glazed pottery previously thought to have all been imported

from Mexico.

The Nuclear Methods Group (Analytical Chemistry

Division, Chemical Sciences and Technology Laboratory)

develops and applies nuclear analytical techniques for the

determination of elemental compositions, striving for

improvements in accuracy, sensitivity, and selectivity. The

group has pioneered the use of cold neutrons as analytical

probes in two methods, prompt-gamma activation analysis

(PGAA) and neutron depth profiling (NDP). In PGAA, the

amount of a particular analyte is measured by detecting

characteristic gamma-rays emitted by the sample while it is

being irradiated in an intense cold-neutron beam. NDP is

another in-beam method that can characterize the concentration of several elements as a function of depth in the

first few microns below a surface. It accomplishes this

by energy analysis of the charged particles emitted

promptly during neutron bombardment. In addition to

NDP and PGAA, the group has a high level of capability in

two more conventional methods, instrumental and radiochemical neutron activation analysis (INAA and RNAA).

In aggregate, the techniques used by the group are a

powerful set of complementary tools for addressing

analytical problems for both in-house and user programs,

and are used to help certify a large number of NIST

Standard Reference Materials.

The Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration (FDA), directs

and maintains a neutron activation analysis (NAA) facility

at the NCNR. This facility provides agency-wide analytical

support for special investigations and applications research,

complementing other analytical techniques used at FDA

with instrumental, neutron-capture prompt-gamma, and

radiochemical NAA procedures, radioisotope x-ray fluorescence spectrometry (RXRFS), and low-level gamma-ray

detection. This combination of analytical techniques

enables diverse multi-element and radiological information

to be obtained for foods and related materials. The NAA

facility supports agency quality assurance programs by

developing in-house reference materials, by characterizing

food-related reference materials with NIST and other

agencies, and by verifying analyses for FDA’s Total Diet

Study Program. Other studies include the development of

RXRFS methods for screening food ware for the presence

of Pb, Cd and other potentially toxic elements, use of

instrumental NAA to investigate bromate residues in bread

products, use of prompt-gamma NAA to investigate boron

nutrition and its relation to bone strength, and the determination of the elemental compositions of dietary supplements.

The ExxonMobil Research and Engineering

Company is a member of the Participating Research Team

(PRT) that operates, maintains, and conducts research at

the NG-7 30 m SANS instrument and the NG-5 Neutron

Spin Echo Spectrometer. Their mission is to use those

instruments, as well as other neutron scattering

techniques available to them at NCNR, in activities

that complement research at ExxonMobil’s main

laboratories as well as at its affiliates’ laboratories around the world. The aim of these

activities is to deepen understanding of the

nature of ExxonMobil’s products
46

and processes, so

as to improve customer

service and to improve the

return on shareholders’ investment. Accordingly, and taking full

advantage of the unique properties of

neutrons, most of the experiments use

SANS or other neutron techniques to study

the structure and dynamics of hydrocarbon

materials, especially in the fields of polymers,

complex fluids, and petroleum mixtures. ExxonMobil

regards its participation in the NCNR and collaborations with NIST and other PRT members not only as an

excellent investment for the company, but also as a good

way to contribute to the scientific health of the nation.

The NCNR provides its resources to a large number

of researchers from US universities and colleges, and the

latter in turn have provided substantial aid to the construction of NCNR instruments and participation in collaborative

research programs. For example, the Johns Hopkins

University has taken a leading role in the development of

the MACS spectrometer, and conducts extensive studies of

magnetism and soft condensed matter, involving several

faculty members, as well as engineering staff. The

University of Maryland is likewise heavily involved at the

NCNR, maintaining several researchers at our facility.

Other institutions that have noteworthy long-term commitments at the NCNR are the University of Minnesota

(member of the participating research teams, or PRTs, for

the NG7 SANS instrument and the NG7 reflectometer).

UC Irvine, Johns Hopkins, Penn, Rice, Duke, and

Carnegie-Mellon University are all members of the

CNBT collaboration. The University of Pennsylvania is

also a member of the PRT for the FANS spectrometer.

The U.S. Army Research Laboratory has

sponsored a scientific program based at the NCNR for

three decades. Among its accomplishments are investigations of materials at high pressure, determinations of

crystal structure of molecular solids, and the initiation of

residual stress measurements at the NCNR.
47

Operations

The NIST neutron source operated for 255 full power

(20 MW) days or approximately 100 % of the

scheduled time. A typical operating year consists of seven

cycles. A cycle has 38 days of continuous full power

operation, followed by 11 days of shutdown maintenance,

refueling, and startup preparations. The number of

operating days in this fiscal year has increased significantly

over the previous year because of improvements to the

physical systems. The new shim arm seals have reduced

leakage as expected and a sample of seal material undergoing testing has exhibited no noticeable corrosion. The new

cooling tower has performed well, allowing full power

operation through all of the summer of 2002. All work has

been completed on the Thermal Column Tank Cooling

System, fulfilling the design requirement to provide cooling

without drawing water or helium from the main heavy

water systems. A second pump was added and a purification loop was installed, with purification of the system

heavy water achieved using particulate filters and an ion

exchanger column. The system has had no adverse affect

on the operating schedule; a

replacement tank has been

fabricated for future installation. Other upgrades accomplished in FY2003 include the

permanent addition of camera

equipment for monitoring

refueling operations and

replacement of the electronics

for both intermediate range

nuclear channels. These new

electronics have worked well

and are also serving as an

evaluation platform to determine the type of replacement

instrument for all of the

nuclear channels.

All security measures

requested by the U. S. Nuclear Regulatory Commission for

the facility have been implemented fully. Items necessary

for 20 more years of operation, such as secondary cooling

water pumps and motors, control rods, heavy water, and a

new operating console, have been acquired, are in production, or are in various stages of planning.

Recently licensed as NCNR operators are: (left photo) Randy Strader, and (right photo) Greg Heller and

Chris Grant. Jim Moody (far right) is in training as an operator.
48

Facility Developments

Data Analysis,

Visualization, and Modeling

Software Developments

This has been an exciting year in the area of

data visualization and analysis software development

with numerous additions to the NCNR’s growing suite

of software tools as well as many enhanced capabilities

in the existing software. Version 1.0 of DAVE (the Data

Analysis and Visualization Environment), is a comprehensive set of software tools developed for the interpretation

of inelastic neutron scattering data, and was released last

year (see Fig. 1). DAVE is a feature-rich application under

extensive development as its user base grows and additional requests are accommodated. Some of the new

capabilities added this year include enhancements in

visualization with fully customizable plots in one and two

dimensions, proper handling for single crystal time-offlight data, new capabilities for exploring and analyzing

multiple datasets, and a new module allowing users to fit

parameterized models of S(Q,ω) to 2-dimensional data.

These additions are currently undergoing extensive beta

testing and are available in the current development version

of DAVE (http://www.ncnr.nist.gov/dave/).

The Igor Pro-based SANS data reduction and

analysis software developed at the NCNR has proven to be

very popular with facility users. The Ultra Small-Angle

Neutron Scattering (USANS) instrument at BT-5 extends

the lowest momentum transfer Q reached by SANS by

nearly two orders of magnitude. In response to users’

needs, Igor Pro-based software has been developed to

allow user-friendly reduction of USANS data sets. The

software allows experimenters to inspect raw USANS data

and to interactively reduce them into a fully corrected

USANS data set (see Fig. 2).

A team from the NCNR, the University of Maryland,

Baltimore County, and from Los Alamos National Laboratory (LANL) are developing a SANS-Modeler software

package. This package is a web-based (http://

sans.chem.umbc.edu/) molecular modeling tool to aid

users performing Small Angle Neutron Scattering experiments on biological macromolecules. The web site is a

compilation of software developed over the years at both

the NIST Center for Neutron Research and LANL.

Fig. 1. Victoria Garcia-Sakai and Janna Maranas (Pennsylvania State

University) inspect some of their DCS data using the DAVE software

package.

Currently users can calculate the contrast factor for

nucleic acids and proteins as well as for protein/nucleic

acid complexes, simulate a molecular structure using

simple shapes such as spheres, cylinders and helices and

generate model SANS data, and align two macromolecular

structures from which the model SANS data can be

calculated. Furthermore users can calculate model SANS

data from high-resolution x-ray crystallography or NMR

structures that are written in the format recognized by the

Research Collaboratory for Structural Bioinformatics

(RCSB) Protein Data Bank (PDB). In addition to the online modeling capabilities SANS-Modeler also allows 3-D

visualization of protein structures. Currently, SANSModeler is being tested and planned release to the general

SANS community is scheduled for later this year.

Over the past year our reflectometry fitting software

has been greatly refined and it is now available for different

operating system platforms, including Linux, Windows,

Mac OS/X, and SGI’s IRIX. Installation is as simple as

dragging a single file onto the desktop. With its context

sensitive help facility and graphical user interface it is easy

for novice users to analyze their data. With access to the

underlying scripting language, it is a powerful and flexible

tool for experts. This software is gaining wide acceptance

in the NCNR reflectivity user community as the standard

tool for data reduction and analysis. From the NOBUGS

Photography by Lynn A. Shuman
49

Facility Developments

2002 conference in November and from presentations

inside NIST, we are now interacting with other US neutron

facilities to further improve the software and explore the

possibility for broader use.

EXPGUI, the NCNR-developed graphical interface to

the Los Alamos GSAS crystallography package continues

to impact the Rietveld community. In the past year, the

software was downloaded well over a thousand times and

the web pages were viewed more than one hundred

thousand times. The user-friendly nature of the EXPGUI

package is attractive to students and the program has now

been integrated into a number of university courses. It has

also been widely taught in workshops, for example at the

recent Oak Ridge National Lab’s NICEST workshop, the

Georgia Tech Advanced Rietveld Short Course and the

American Crystallographic Society’s annual summer

crystallography course. Requests for program enhancements, as well as new features added to the software, are

tracked on the NCNR website (www.ncnr.nist.gov/xtal/

software/expgui/wishlist.html). In FY2003, requests

outstripped the Crystallography team’s ability to respond.

The major new features added to the code were:

• CIF: The IUCr’s standard format, the crystallographic information file (CIF), including the powder

diffraction extensions (pdCIF) have been implemented.

[Toby, B. H., Von Dreele, R. B. & Larson, A. C. “Reporting

of Rietveld Results Using pdCIF: GSAS2CIF,” J. Appl.

Cryst. 36, 1290 (2003).]

• Instrument parameter file editor: GSAS instrument

parameter files describe the diffraction instrument and

provide a starting point for the refinement. While users at

the NCNR receive an accurate file for BT-1, building or

finding an appropriate file for many other instruments has

been a major trouble spot for many other users. The new

editor shows the contents of the file and the options in an

easy-to-understand fashion. It can also be used to create

new instrument parameter files “from scratch.”

• POWPREF warning: The POWPREF program is

used in GSAS to map reflections to the powder diffraction

data points. It must be rerun when the data range changes

or if phases are added. Neophyte (and occasionally

experienced) users may run into problems when they fail

to run this program. EXPGUI now tracks these types of

actions and reminds users to run the POWPREF program

before attempting a refinement.

• Other enhancements include: new data and

coordinate export abilities, ability to read in multiple

datasets in a single step. Also, all reported bugs were fixed.

Data Acquisition

and Instrument Control

Nearly every NCNR instrument relies on motors to

position neutron optical elements and to orient the sample.

The NCNR is in the process of replacing the motor control

hardware with a new architecture to improve the serviceability and reliability of these critical systems (Fig. 3). The

new architecture employs VME-based computers and

motor indexers with an NCNR-designed chassis for

multiple motor driver modules. Extensive use is made of

commercial, off-the-shelf components through vendorneutral interfaces. The chassis system features standardized connectors, jumpers and dip-switches to facilitate

configuring the motor control system in the field. The

complete system is capable of controlling up to 64 encoder-equipped motors using a full spectrum of motion

control features. The new system has been deployed on

the BT-8 DARTS instrument and on the NG-7 reflectometer.

Another major standardization effort has been

the development of a standard control and

readout interface for linear and area neutron

detectors. This system is a PC-based

histogrammer that interfaces with the

detectors through either vendorFig. 2. A screenshot of USANS data reduction software, showing the

raw scattering of the sample and empty cell, and the (rescaled) corrected

USANS data. The user can override any of the automatically determined

parameters, and the effects are directly visualized in the graph.
50

supplied electronics or through standard

NIM hardware using a highspeed digital I/O bus that is

controlled over Ethernet using a

simple, NCNR-designed protocol. Over

the past year, this system has been successfully used on the NG-1 reflectometer,

NG-1 SANS, and the NG-5 Neutron Spin Echo

Spectrometer.

Sample Environment Equipment

There have been a number of improvements made

to the equipment pool and support infrastructure for

sample environments at the NCNR. The 9 Tesla horizontal

field superconducting magnet with single crystal windows

has been customized for SANS and USANS studies

(Fig. 4). A pulse tube refrigerator capable of temperatures

in the range of 4 K to 300 K has been integrated into the

BT-1 powder diffractometer as a dedicated unit. A new

closed-cycle refrigerator was added for general purpose

use providing sample temperatures over a wide range: 7 K

to 800 K. A new liquid helium cryostat, designed especially

for the DCS instrument, was purchased and provides

temperatures in the range of 1.5 K to 300 K. New support

equipment includes: needle valve heaters for clearing

blocked liquid helium cryostats, helium transfer stations at

key locations, a new equipment preparation area at the

north end of the Guide Hall, and new or updated user

manuals for most of the equipment.

BT-7 Double Focusing Triple Axis

Spectrometer Development

A new double focusing triple axis spectrometer for

BT-7, is at an advanced stage of development, with

installation planned for early next year. Highlights from

this year’s activities include delivery of the monochromator

drum shields, completion of the double focused monochromator using Cu(311) and PG(002), installation of the

instrument shutter system and incident beam collimation

system, completion of the sample goniometer “bucket,”

and final testing of the air pad floor system. Final design,

fabrication and testing are currently underway for the new

analyzer system and for the data acquisition and instrument

control system.

Fig. 3. Doris Kendig (NCNR) adjusts motor drivers on the new motor

control system.

Fig. 4. Rachel Anderman (NCNR) fills the new 9T horizontal field

superconducting magnet with helium.

Photography by Lynn A. Shuman Photography by Lynn A. Shuman
51

Publications

51

Abdurashitov, J. N., Gavrin, V. N., Girin, S. V., Gorbachev, V. V.,

Gurkina, P. P., Ibragimova, T. V., Kalikhov, A. V., Khairnasov,

N. G., Knodel, T. V., Mirmov, I. N., Shikhin, A. A., Veretenkin,

E. P., Vermul, V. M., Yants, V. E., Zatsepin, G. T., Bowles, T.

J., Teasdale, W. A., Nico, J. S., Cleveland, B. T., Elliott, S. R.,

Wilkerson, J. F., “Solar Neutrino Flux Measurements by the

Soviet-American Gallium Experiment (SAGE) for Half the 22-

Year Solar Cycle,” Jour. Exp. Th. Phys. 95 (2), 181 (2002).

Adams, C. P., Lynn, J. W., Smolyaninova, V. N., Biswas, A., Greene,

R. L., Ratcliff, W., Cheong, S.-W., Mukovskii, Y. M.,

Shulyatev, D. A., “First-Order Nature of the Ferromagnetic

Phase Transition in (La-Ca)MnO3

 Near Optimal Doping,”

Phys. Rev. B, in press.

Agamalian, M., Iolin, E., Kaiser, H., Rehm, C., Werner, S. A., “A

New Dynamical Diffraction-Based Technique of Residual

Stress Measurements in Thin Films,” Appl. Phys. A 74, S1686

(2002).

Allen, A. J., Berk, N. F., Ilavsky, J., Long, G. G., “Multiple SmallAngle Neutron Scattering Studies of Anisotropic Materials,”

Appl. Phys. A 74, S937 (2002).

Allen, J. W., Aronson, M., Boebinger, G. S., Broholm, C., Lance

Cooper, S., Crow, J. E., Hammel, P. C., Lander, G., “Future

Probes in Materials Science,” Physica B 318, 12 (2002).

Anderson, D. L., Mackey, E. A., “Improvements in Food Analysis

by Thermal Capture Prompt Gamma-ray Spectrometry,” J.

Radioanal. Nucl. Chem., in press.

Angell, C. A., Yue, Y.-Z., Wang, L.-M., Copley, J. R. D., Borick, S.,

Mossa, S., “Potential Energy, Relaxation, Vibrational

Dynamics and the Boson Peak, of Hyperquenched Glasses,” J.

Phys. Condens. Matter 15, S1051 (2003).

Annis, B. K., Kim, M.-H., Brown, C., “Comparison of Boson Peaks

in Polypropylenes,” Macromol. 36 (2), 520 (2003).

Azuah, R. T., Glyde, H. R., Scherm, R., Mulders, N., Fak, B.,

“Bose-Einstein Condensation in Liquid He-4 in Vycor,” J.

Low Tem. Phys. 130 (5-6), 557 (2003).

Baklanov, M. R., Kondoh, E., Lin, E. K., Gidley, D. W., Lee, H.-J.,

Mogilnikov, K. P., Sun, J. N., “Comparative Study of Porous

SOG Films with Different Non-Destructive Instrumentation,”

in Proceedings of the National Interconnect Technology

Conference, in press.

Bao, W., Trevino, S. F., Lynn, J. W., Pagliuso, P. G., Sarrao, J. L.,

Thompson, J. D., Fisk, Z., “Effect of Pressure on Magnetic

Structure in Heavy Fermion CeRhIn5

,” Appl. Phys. A 74, S557

(2002).

Berk, N. F., Majkrzak, C. F., “Wavelet Analysis Neutron

Reflectivity,” Langmuir, in press.

Bhatia, S., Barker, J., Mourchid, A., “Scattering of Disk-Like

Particle Suspensions: Evidence for Repulsive Interactions and

Large Length Scale Structure from Static Light Scattering and

Ultra-Small-Angle Neutron Scattering,” Langmuir 19 (3), 532

(2003).

Biggs, S., Walker, L. M., Kline, S. R., “The Formation of an

Irreversibly Adsorbed and Organized Micelle Layer at the

Solid-Liquid Interface,” Nanoletters 2 (12), 1409 (2002).

Bishop, R. L., Blackman, M. J., “Instrumental Neutron Activation

Analysis of Archaeological Ceramics: Scale and

Interpretation,” Acc. Chem. Res., in press.

Black, T. C., Huffman, P. R., Jacobson, D. L., Snow, W. M., Schoen,

K., Arif, M., Kaiser, H., Lamoreaux, S. K., Werner, S. A.,

“Precision Neutron Interferometric Measurement of the n-d

Coherent Neutron Scattering Length and Consequences for

Models of Three-Nucleon Forces,” Phys. Rev. Lett. 90,

192502 (2003).

Blackman, M. J., Redford, S., “Northern Syrian Luster and

Fruitware: Petrographic and Chemical Implications for

Productions and Distribution,” Antiquity, in press.

Blasie, J. K., Kneller, L. R., Majkrzak, C. F., “Neutron

Interferometry of Vectorially-Oriented Single Monolayers of

Membrane Proteins and Their Artificial Synthetic Maquettes,”

Abstr. Pap. Am. Chem. Soc. 224, 123 (2002).

Böni, P., Clementyev, E., Stadler, C. H., Roessli, B., Shirane, G.,

Werner, S. A., “Fincher-Burke Excitations in Single-Q

Chromium,” Appl. Phys. A 74, S716 (2002).

Bordallo, H. N., Chapon, L. C., Cook., J. C., Copley, J. R. D.,

Goremychkin, E., Kern, S., Lee, S.–H., Yildirim, T., Manson,

J. L., “Spin Excitations in 3D Molecular Magnets Probed by

Neutron Scattering,” Appl. Phys. A 74, S634 (2002).

Borgoul-Maciejczyk, P., Ondov, J. M., “Heterogenous Nature of

Metallic Components in Baltimore Particulate Matter,”

Environ. Sci. Technol., in press.

Borodin, O., Douglas, R., Smith, G. D., Trouw, F., Petrucci, S.,

“MD Simulations and Experimental Study of Structure,

Dynamics, and Thermodynamics of Poly(ethylene oxide) and

Its Oligomers,” J. Phys. Chem. B 107, 6813 (2003).

Bossev, D. P., Ferdinand, S., Paulaitis, M. E., “Effect of Pressure on

Microstructure in Water-in-Oil and Oil–in-Water

Microemulsions for C12E5

 n-Octane/D20 Mixtures,” Langmuir,

in press.

Boukari, H., Allen, A. J., Long, G. G., Ilavsky, J., Wallace, J. S.,

Berndt, C. C., Herman, H., “Small-Angle Neutron Scattering

Study of the Role of Feedstock, Particle Size on the

Microstructural Behavior of Plasma-Sprayed Yttria-Stabilized

Zirconia Deposits,” J. Mater. Res. 18 (3), 624 (2003).

Broholm, C., Aeppli, G., “Dynamic Correlations in Quantum

Magnets,” to appear in Strong Interactions in Low

Dimensions, edited by D. Baeriswyl, and L. Degiorgi,

(Kluwer), in press.

Brown, C. M., Manson, J. L., “Solid State Ligand Dynamics in

Interpreting Mn[N(CN)2]2(pyrazine): A Neutron

Spectroscopy Study,” J. Amer. Chem. Soc. 124 (42), 12600

(2002).
52

Caffrey, P. F., Ondov, J. M., “Dry Deposition of Elemental Aerosol

Constituents to Lake Michigan Surface Waters, by Size and by

Source,” Environ. Sci. Technol., in press.

Caffrey, P. F., Ondov, J. M., “Dry Removal of Elemental Aerosol

Particulate Constituents in Near Shore Gradient of Southern

Lake Michigan,” Environ. Sci. Tech., in press.

Campbell, B. J., Sinha, S. K., Osborn, R., Rosenkranz, S., VasiliuDoloc, L., Mitchell, J. F., Islam, Z., Seeck, O. H., Lynn, J. W.,

“Polaronic Orbital Polarization in a Layered Colossal

Magnetoresistive Manganite,” Phys. Rev. B 67, R020409

(2003).

Cappelletti, R. L., “MSEL, FY2002 Programs and

Accomplishments,” NIST IR, 6908 (2002).

Cappelletti, R. L., “NCNR 2002 NIST Center for Neutron Research

Accomplishments and Opportunities,” NIST SP 993 (2002).

Cava, R. J., DiSalvo, F. J., Brus, L. E., Dunbar, K. R., Gorman, C.

B., Maile, S. M., Interrante, L. V., Musfeldt, J. L., Navrotsky,

A., Nuzzo, R. G., Pickett, W. E., Wilkinson, A. P., Ahn, C.,

Allen, J. W., Burns, P. C., Ceder, G., Chidsey, C. E. D., Clegg,

W., Coronado, E., Dai, H., Deem, M. W., Dunn, B. S., Galli,

G., Jacobson, A. J., Kanatzidis, M., Lin, W., Manthiram, A.,

Mrksich, M., Norris, D. J., Nozik, A. J., Peng, X., Rawn, C.,

Rolison, D., Singh, D. J., Toby, B. H., Tolbert, S., Wiesner, U.

B., Woodward, P. M., Yang, P., “Future Directions in Solid

State Chemistry: Report of the NSF-Sponsored Workshop,”

Progr. Solid State Chem. 30, 1 (2002).

Chakoumakos, B. C., Rawn, C. J., Rondinone, A. J., Marshall, S. L.,

Stern, L. A., Circone, S., Kirby, S. H., Jones, C. Y., Toby, B.

H., Ishii, Y., “The Use of Rigid Body Constraints in Rietveld

Refinements of Neutron Diffraction Data of Clathrate

Hydrates,” in Proceeding of the 4th International Conference

on Gas Hydrates, (Yokohama, Japan, 2002), in press.

Chakoumakos, B. C., Rawn, C. J., Rondinone, A. J., Stern, L. A.,

Circone, S., Kirby, S. H., Ishii, Y., Jones, C. Y., Toby, B. H.,

“Temperature Dependence of Polyhedral Cage Volumes in

Clathrate Hydrates” Can. J. Phys. 81 (1-2), 183 (2003).

Chen, S.-H., Chen, W.-R., Mallamace, F., “The Glass-to-Glass

Transition and Its End Point in a Copolymer Micellar

System,” Science, 300, 619 (2003).

Chen, S.-H., Mallamace, F., Faraone, A., Gambadauro, P.,

Lombardo, D., Chen, W. R., “Observation of a Re-Entrant

Kinetic Glass Transition in a Micellar System with

Temperature-Dependent Attractive Interaction,” Eur. Phys. J.

E 9, 283 (2002).

Chen, W. C., Bailey, C., Borchers, J. A., Farrow, R. F. C., Gentile, T.

R., Hussey, D. H., Majkrzak, C. F., O’Donovan, K. V.,

Remmes, N., Snow, W. M., Thompson, A. K., “Polarized 3

He

Analyzers for Neutron Reflectometry,” Physica B 335, 196

(2003).

Cheng, X., Fisher, J. W., Yen, B. T., Roy, S., Prask, H. J., GnäupelHerold, T., “Residual Stress Modification by Post-Weld

Treatment and Its Beneficial Effect on Fatigue Strength of

Welded Structures,” ASM Matls. Solutions Conf. & Show,

(Columbus, OH, 2002), in press.

Chen-Mayer, H. H., Lamaze, G. P., Coakley, K. J., Satija, S. K.,

“Two Aspects of Thin Film Analysis: Boron Profile and

Scattering Length Density Profile,” Nucl. Inst. Meth. A 505,

531 (2003).

Choi, E. J., Foster, M. D., Daly, S., Tilton, R., Przbycien, T.,

Majkrzak, C. F., Witte, P., Menzel, H., “Effect of Flow on

Human Serum Alumin Adsorption to Self-Assembled

Monolayers of Varying Packing Density,” J. Colloid Interf.

Sci., in press.

Choi, H. D., Firestone, R. B., Lindstrom, R. M., Molnar, G. L.,

Reddy, A. V. R., Tan, V. H., Zhou, C. M., Paviottia-Corcuera,

R. A., Trkov, A., “Development of a Database for Prompt

Gamma-Ray Neutron Activation Analysis,” J. Nucl. Sci. Tech.,

in press.

Choi, E. J., Foster, M. D., Daly, S., Tilton, R., Przbycien, T.,

Majkrzak, C. F., Witte, P., Menzel, H., “Effect of Flow on

Human Serum Alumin Adsorption to Self-Assembled

Monolayers of Varying Packing Density,” Langmuir 19 (13),

5464 (2003).

Chong, K. P., Sung, L., VanLandingham, M. R., “Solid

Micromechanics: Research and Challenges,” in Proceedings of

the 13th Micromechanics Europe (MME 2002) Workshop,

(Sinaia, Romania, Oct. 6-8, 2002), in press.

Chowdhuri, Z., Hansen, G., Snow, W. M., Keith, C. D., Thompson,

A. K., Dewey, M. S., Gilliam, D. M., Nico, J. S., Wietfeldt, F.

E., Lozowski, W. M., Jane, V., Greene, G. L., “A Cryogenic

Radiometer for Absolute Neutron Rate Measurement,” Rev.

Sci. Instrum., in press.

Clarke, W. B., Guscott, R., Lindstrom, R. M., “Binding of Lithium

and Boron to Human Plasma Proteins II: Results for a Bipolar

Not on Lithium Therapy,” Biol. Trace Element Res., in press.

Coakley, K. J., Chowdhuri, Z., Snow, W. M., Richardson, J. M.,

Dewey, M. S., “Estimation of Neutron Mean Wavelength

From Rocking Curve Data,” Meas. Sci. Technol. 14 (1), 131

(2003).

Copley, J. R. D., “An Acceptance Diagram Analysis of the

Contaminant Pulse Removal Problem with Direct Geometry

Neutron Chopper Spetrometers,” Nucl. Inst. Meth. A, in

press.

Copley, J. R. D., Cook, J. C., “The Disk Chopper Spectrometer at

NIST: A New Instrument for Quasielastic Neutron Scattering

Studies,” Chem. Phys. 292, 477 (2003).

Cranswick, L. M. D., Mumme, W. G., Grey, I. E., Roth, R. S.,

Bordet, P., “A New Octahedral Tilt System in the Perovskite

Phase Ca3

Nb2O8,” J. Solid State Chem. 172, 178 (2003).

Dag, S., Gulseren, O., Ciraci, S., Yildirim, T., “Electronics Structure

of the Contact Between Carbon Nanotube and Metal

Electrodes,” Appl. Phys. Lett., in press.

Dag, S., Gulseren, O., Yildirim, T., Ciraci, S., “Oxidation of Carbon

Nanotubes: Structure and Energetics,” Phys. Rev. B 67,

165424 (2003).

Dattelbaum, A., He, L., Tsui, F., Martin, J. D., “Synthesis and

Characterization of Cu2ZrCl6: A Thermochromic, Van Vleck

Paramagnet,” J. Alloys and Comp. 338, 173 (2002).

DeBruyn, H., Gilbert, R. G., White, J. W., Schulz, J. C.,

“Characterization of Electrosterically Stabilized Polystyrene

Latex; Implications for Radical Entry Kinetics,” Polymer 44

(16), 4411 (2003).

DeBruyn, H., Gilbert, R. G., White, J. W., Schulz, J. C., “SANS

Study of Electrosterically Stabilized Polystyrene Latex,”

Langmuir, in press.
Publications

53

DeSanto, P., Buttrey, J., Grasselli, R. K., Lugmair, C. G., Volpe, A.

F., Toby, B. H., Vogt, T., “Structural Characterization of the

Orthorhombic Phase M2 in MoVNbTeO Propane

Ammoxidation Catalyst,” Topics in Catalysis, in press.

DeWall, J., Dimeo, R. M., Sokol, P. E., “Slow Diffusion of

Molecular Hydrogen in Zeolite 13X,” J. Low Temp. Phys. 129

(3-4), 171 (2002).

Dimeo, R. M., “Visualization and Measurement of Quantum

Rotational Dynamics,” Am. J. Phys., 71 (9), 885 (2003).

Dimeo, R. M., Chowdhuri, Z., Meyer, A., Gehring, P. M.,

Neumann, D. A., “The NIST High-Flux Backscattering

Spectrometer,” Appl. Phys. A 74, S311 (2002).

Dimeo, R. M., Neumann, D. A., “The Effects of Confinement on

Rotational Tunneling,” Appl. Phys. A 74, S1382 (2002).

DiNoia, T. P., Van Zanten, J. H., Fetters, L. J., Wright, P. J., Kline,

S. R., Garach-Domech, A., McHugh, M. A., “Impact of

Supercritical Fluid Solvent Quality on Polymer Conformation

in Semidilute Solutions: SANS Data for Poly(ethylene-co-1-

butene) in Dimethyl Ether to Kilobar Pressures,” Macromol.,

in press.

Divita, F., Terry, J., Kidwell, C. A., Ondov, J. M., Pandis, S.,

“Characterization of Primary Aerosol Emissions from a

Municipal Incinerator Via Ground-Level Sampling with a

Micro-Orifice Impactor.” Atmos. Environ., in press.

Downing, R. G., Iyengar, G. V., “Methodological Issues in the

Analytical Determination of Boron,” Environ. Health

Perspect., in press.

Dubsky, J., Prask, H. J., Matejicek, J., Gnäupel-Herold, T.,

“Stresses in Plasma Sprayed Cr2

O3 Coatings Measured by

Neutron Diffraction,” Appl. Phys. A 74, S1115 (2002).

Duckham, A., Zhang, D. Z., Liang, D., Luzin, V., Cammarata, R. C.,

Leheny, R. L., Chien, C. L., Weihs, T. P., “Temperature

Dependent Mechanical Properties of Ultra-Fine Grained

FeCo-2V,” Acta Mater. 51 (14), 4083 (2003).

Dullo, A. R., Ruddy, F. H., Seidel, J. G., Adams, J. M., Nico, J. S.,

Gilliam, D. M., “The Neutron Response of Miniature Silicon

Carbide Semiconductor Detectors,” Nucl. Instrum. Meth. A.

498 (1-3), 415 (2003).

Durgun, E., Dag, S., Bagci, V. M. K., Gulseren, O., Yildirim, T.,

Ciraci, S., “Systematic Study of Adsorption of Single Atoms

on a Carbon Nanotube,” Phys. Rev. B 67, 201401 (2003).

Eitouni, H. B., Hahn, H., Balsara, N. P., Pople, J. A., Hempenius,

M. A., “Thermodynamic Interactions in Organometallic Block

Copolymers: Poly(styrene-block-ferrocenyldimethylsilane),”

Macromol. 35, 7765 (2002).

Elliot, J., Meuse, V., Silin, V., Krueger, S., Woodward, J. T., PetralliMallow, T. P., Plant, A. L., “Biomedical Membranes on Metal

Supports: Opportunites and Challenges,” in Proceedings of the

Biomolecular Films: Design, Function, and Application, edited

by J. Rusling (New York, Marcel Dekker, Inc., 2003), p. 99.

Faraone, A., Liu, L., Mou, C.-Y., Shih, P.-C., Brown, C. M., Copley,

J. R. D., Dimeo, R. M., Chen, S.-H., “Dynamics of

Supercooled Water in Mesoporous Silica Matrix MCM-48-S,”

Eur. Phys. J. E, in press.

Faraone, A., Liu, L., Chen, S.-H., Mou, C.-Y., Shih, P.-C., Copley, J.

R. D., “Translational and Rotational Dynamics of Water in

Mesoporous Silica Materials: MCM-41-S and MCM-48-S,” J.

Chem. Phys. 119, 3963 (2003).

Garvey, C. J., Parker, I. H., Simon, G. P., Whittaker, A. K., Knott,

R. B., “An Experimental Study by NMR and SANS of the

Ambient Hydration of Paper,” in Proceedings of the 12th

Fundamental Research Symposium, (Pulp and Paper

Fundamental Research Society, Oxford), in press.

Gaulin, B. D., Mao, M., Wiebe, C. R., Qiu, Y., Shapiro, S. M.,

Broholm, C., Lee, S.-H., Garrett, J. D., “Spin and Lattice

Excitations in the Heavy Fermion Superconductor UNi2Al3,”

Phys. Rev. B 66 (17), 174520 (2002).

Gawrys, K. L., Spiecker, P. M., Kilpatrick, P. K., “The Role of

Asphaltene Solubility and Chemistry on Asphaltene

Aggregation,” Petroleum Science and Technology 21, 461

(2003).

Gehring, P. M., “Summer School on Methods and Applications of

Neutron Spectroscopy Held at NIST,” Neutron News, in

press.

Geissler, E., Hecht, A. M., Rochas, C., Horkay, F., Bley, F., Livet,

F., “Structure and Dynamics of Silica-Filled Polymers by

SANS and Coherent SAXS,” Macromol. Symp. 190, 23

(2002).

Gentile, T. R., Hayden, M. E., Barlow, M. J., “Comparison of

Metastability Optical Pumping Sources,” J. Opt. Am. B, in

press.

Gibson, W. M., Schultz, A. J., Chen-Mayer, H. H., Mildner, D. F.

R., Gnäupel-Herold, T., Miller, M. E., Prask, H. J., Vitt, R.,

Youngman, R., Carpenter, J. M., “Polycapillary Focusing

Optic for Small Sample Neutron Crystallography,” J. Appl.

Cryst 35 677 (2002).

Gilliam, D. M., Thompson, A. K., Nico, J. S., “A Neutron Sensor

For Detection of Nuclear Materials In Transport,” AIP

Conference Proceedings, (Unattended Radiation Sensor

Systems for Remote Applications), edited by J. I. Trombka,

D. P. Spears, and P. H. Solomon, 632, 0-7354-0087 (American

Institute of Physics), p. 291.

Glagolenko, I. Y., Carney, K. P., Kern, S., Goremychkin, E. A.,

Udovic, T. J., Copley, J. R. D., Cook, J. C., “Quantitative

Analysis of UH3

 in U Metal and UO2 Matrices by Neutron

Vibrational Spectroscopy,” Appl. Phys. A 74, S1397 (2002).

Glinka, C. J., “Summer School on SANS and Reflectometry Held at

NIST,” Neutron News 13 (4), 6 (2002).

Gnäupel-Herold, T., “Single Crystal Elastic Constants From Powder

Measurements,” in Proceedings of Accuracy in Powder

Diffraction. III (NIST Special Publication), in press.

Gnäupel-Herold, T., Prask, H. J., Biancaniello, F. S., “Residual

Stresses and Elastic Constants in Thermal Deposits”, in

Recent Advances in Experimental Mechanics – In Honor of

Isaac M. Daniel, edited by E.E. Gdoutos, (Kluwer Academic

Publishers, Dordrecht 2002), in press.

Goodrich, R. G., Young, D. P., Hall, D., Fisk, Z., Harrison, N.,

Betts, J., Migliori, A., Woodward, F. M., Lynn, J. W., “New

Aspects of the Temperature - Magnetic Field Phase Diagram

of CeB6

,” Phys. Rev. B, in press.

Granado, E., Huang, Q., Lynn, J. W., Gopalakrishnan, J., Greene, R.

L., Ramesha, K., “Spin-Orbital Ordering and Mesoscopic

Phase Separation in the Double Perovskite Ca2

FeReO6,” Phys.

Rev. B 66 (6), 064409 (2002).
54

Granado, E., Ling, C. D., Neumeier, J. J., Lynn, J. W., Argyriou, D.

N., “Inhomogeneous Magnetism in La-doped CaMnO3: (I)

Nanometric-Scale Spin Clusters and Long-Range Spin

Canting,” Phys. Rev. B, in press.

Granado, E., Martinho, H., Sercheli, M. S., Pagliuso, P. G., Jackson,

D., Torelli, M., Lynn, J. W., Rettori, C., Fisk, Z., Oseroff, S.

B., “Unconventional Metallic Magnetism in LaCrSb3

,” Phys.

Rev. Lett. 89 (10), 107204 (2002).

Grohol, D., Huang, Q., Toby, B., Lynn, J. W., Lee, Y. S., Nocera, D.

G., “Powder Neutron Diffraction Analysis and Magnetic

Structure of Kagomé type Vanadium Jarosite

NaV3

(OD)6(SO4)2,” Phys. Rev. B 68, 094404 (2003).

Gruell, H., Sung, L., Karim, A., Douglas, J. F., Satija, S. K., Han, C.

C., “Surface Segregation of a Symmetrical Segregating Polymer

Blend Film Above and Below the Critical Point of Phase

Separation,” Europhys. Lett., in press.

Gu, X., Raghavan, D., Ho, D. L., Sung, M. R., VanLandingham, M.

R., Nguyen, T., “Nanocharacterization of Surface and Interface

of Different Epoxy Network,” in Proceedings of the MRS Fall

2001 Meeting, edited by Frank, C. W., in press.

 Gu, X., Sung, L., Ho, D. L., Michaels, C. A., Nguyen, D., Jean, Y.

C. Nguyen, T., “Surface and Interface Properties of PVDF/

Acrylic Copolymer Blends Before and After UV Exposure,” in

Proceedings of the 80th Annual Meeting Technical Program

(Oct. 30-Nov.1, New Orleans, LA, 2002), in press.

Guàrdia, E., Martí, J., Padró, J. A., Saiz, L., Komolkin, A. V.,

“Dynamics in Hydrogen Bonded Liquids: Water and

Alcohols,” J. Molec. Liq. 96-97, 3 (2002).

Gulseren, O., Yildirim, T., Ciraci, S., “Effects of Hydrogen

Adsorption on Single Wall Carbon Nanotubes: Metallic

Hydrogen Decoration,: Phys. Rev. B 66, 121401 (2002).

Gulseren, O., Yildirim, T., Ciraci, S., “Formation of Quantum

Structures on a Single Nanotube by Modulation Hydrogen

Adsorption,” Phys. Rev. B, in press.

Gulseren, O., Yildirim, T., Ciraci, S., Kilic, C., “Reversible BandGap Engineering in Carbon Nanotubes by Radical

Deformation,” Phys. Rev. B 65, 155410 (2002).

Guo, H. K., Tao, R. B., Lin, M. Y., “Quantitative Analysis of Rod

Like Micelle Solutions Viscosity Using Microscopic

Parameters,” Int. J. Mod. Phys. B 17 (1-2), 119 (2003).

Hammouda, B., Ho, D., Kline, S., “SANS from Poly(ethylene oxide)

Water Systems,” Macromol. 35, 8578 (2002).

Hanley, H. J. M., Muzny, C. D., Ho, D. L., Glinka, C. J., “A SmallAngle Neutron Scattering Study of a Commercial Organoclay

Dispersion,” Langmuir 19, 5575 (2003).

Harris, A. B., Aharony, A., Entin-Wholman, O., Korenblit, I. Ya.,

Yildirim, T., “Landau Expansion for the Kugel-Khomskii t2g

Hamiltonian,” Phys. Rev. B, in press.

Harris, A. B., Yildirim, T., Aharony, A., Entin-Wohlman, O.,

Korenblit, I. Ya., “Hidden Symmetries and Their

Consequences in t2g Cubic Perovskites,” Phys. Rev. B, in

press.

Harris, A. B., Yildirim, T., Aharony, A., Entin-Wohlman, O.,

Korenblit, I. Ya., “Unusual Symmetries in the KugelKhomskii-Hamiltonian,” Phys. Rev. Lett., in press.

Harris, S. P., Heller, W. T., Greaser, M. L., Moss, R. L., Trewhella,

J., “Solutions Structure of Heavy Meromyosin by Small Angle

Scattering,” J. Bio. Chem. 278, 6034 (2003).

Hase I., Ikeda S. I., Shirakawa N., Stalick J. K., “Electronic Structure

of Sr2

MoO4,” J. Low. Temp. Phys. 131 (3-4), 269 (2003).

Hassan, P. A., Fritz, G., Kaler, E. W., “Small Angle Neutron

Scattering Study of Sodium Dodecyl Sulfate Micellar Growth

Driven by Addition of a Hydrotropic Salt,” J. Coll. Interface

Sci. 257 (1), 154 (2003).

Hayashi, M., Hashimoto, T., Weber, M., Gruell, H., Esker, A., Han,

C. C., Satija, S. K., “Transient Interface Instability in Bilayer

Polymer Films as Observed by Neutron Reflectivity Studies,”

Macromol., in press.

Heath, C. H., Streletzky, K., Wyslouzil, B. E., Wolk, J., Strey, R.,

“H2

O-D2O Condensation in a Supersonic Nozzle,” J Chem.

Phys. 117 (13), 6176 (2002).

Heath, C. H., Streletzky, K. A., Wyslouzil, B. E., Wolk, J., Strey, R.,

“Small Angle Neutron Scattering From D2

O-H2O

Nanodroplets and Binary Nucleation Rates in a Supersonic

Nozzle,” J. Chem Phys. 118 (12), 5465 (2003).

Hecht, A. M., Horkay, F., Geissler, E., “Thermal Fluctuations in

Polymer Gels Investigated by Neutron Spin Echo and

Dynamic Light Scattering,” Macromol. 35, 8552 (2002).

Hedden, R. C., Bauer, B. J., “Structure and Dimensions of

PAMAM/PEG Dendrimer-Star Polymers,” Macromol. 36 (6),

1829 (2003).

Hedden, R. C., Lee, H. J., Bauer, B. J., Soles, C. L., Wu, W. L., Lin,

E. K., “Measurement of Pore Size and Matrix Characteristics

in Low-k Dielectrics by Neutron Contrast Variation,” in

Proceedings of the International Conference on

Characterization and Metrology for ULSI Technology, (March,

2003, Austin TX), in press.

Heller, W. T., Anusamhadneh, E., Finley, N., Rosevear, P. R.,

Trewhella, J., “The Solution Structure of a Cardiac Troponin

C- Troponin I- Troponin T Complex Shows a Somewhat

Compact Troponin C Interacting with an Extended Troponin

I- Troponin T Component,” Biochem. 41, 15654 (2002).

Henrickson, R. C., Vandiver, P. B., Blackman, M. J., “Lustrous

Black Fine Ware at Gordion, Turkey: A Distinctive Sintered

Slip Technology,” in Materials Research Society Symposium

Proceedings, Materials Issues in Art and Archaeology VI,

edited by P. B. Vandiver, M. Goodway, and J. L. Mass. 712

(2002), p. 391.

Hentze, H. P., Raghavan, S. R., McKelvey, C. A., Kaler, E. W.,

“Silica Hollow Spheres by Templating of Catanionic Vesicles,”

Langmuir 19 (4), 1069 (2003).

Ho, D. L., Glinka, C. J., “Effects of Solvent Solubility Parameters

on Organclay Dispersions,” Chem. Mater. 15 (6), 1309 (2003).

Ho, D. L., Hammouda, B., Kline, S. R., “Clustering of Poly(ethylene

oxide) in Water Revisited,” J. Poly. Sci.: Part B: Poly. Phys.

41, 135 (2003).

Hoffman, A., Seo, J. W., Fitzsimmons, M. R., Siegwart, H.,

Fompeyrine, J., Locquet, J.-P., Dura, J. A., Majkrzak, C. F.,

“Induced Magnetic Moments at a FerromagnetAntiferromagnet Interface,” Phys. Rev. B 66 (22), 220406

(2002).
Publications

55

Horkay, F., Hecht, A. M., Grillo, I., Basser, P. J., Geissler, E.,

“Experimental Evidence for Two Thermodynamic Length

Scales in Neutralized Polyacrylate Gels,” J. Chem. Phys. 117

(20), 9103 (2002).

Huang, Q. Z., Karen, V. L., Santoro, A., Kjekshus, A., Linden, J.,

Pietari, T., Karen, P., “Substitution of Co3+ in YBa2

Fe3O8,” J.

Solid State Chem. 172 (1), 73 (2003).

Huffman, P. R., “An Experiment to Search for Parity-Conserving

Time Reversal Invariance Using Epithermal Neutrons From

the Spallation Neutron Source,” in Astrophysics, Symmetries,

and Applied Physics at Spallation Neutron Sources, (World

Scientific Publishing Co. Pte. Ltd.) 156 (2002).

Huffman, P. R., Arif, M., Dewey, M. S., Gentile, T. R., Gilliam, D.

M., Jacobson, D. L., Nico, J. S., Thompson, A. K., “The

Fundamental Neutron Physics Facilities at NIST,” AIP

Conference Proceedings, Application of Accelerators in

Research and Industry: Seventeenth International Conference

on the Application of Accelerators in Research and Industry,

edited by J. L. Duggan, (Denton, Texas, 12-16 November

2002), 680 (2003).

Huffman, P. R., Coakley, K. J., Dzhosyuk, S. N., Golub, R.,

Korobkina, E., Lamoreaux, S. K., Mattoni, C. E. H.,

McKinsey, D. N., Thompson, A. K., Yang, G. L., Yang, L.,

Doyle, J. M., “Progress Towards Measurement of the Neutron

Lifetime Using Magnetically Trapped Ultracold Neutrons,” in

Proceedings for the “Quark-mixing, CKM Unitarity,”

(Heidelberg, 19-20 September 2002), in press.

Hussey, D., Fan, S., Neff, B., Bailey, C., Snow, W. M., Rich, D.,

Thompson, A. K., Gentile, T. R., Te Velthuis, S. G. E., Felcher,

G. P., “Simultaneous Polarization Analysis of Zeeman

Splitting in Polarized Neutron Reflectometry Using a

Polarized 3

He Neutron-Spin Filter,” Appl. Phys. A 74, S234

(2002).

Ishii, Y., Jones, C. Y., Marshall, S. L., Rawn, C. J., Chakomakos, B.

C., “Structure Study of Tetrahydrofuran Deuterate by

Neutron Powder Diffraction,” JAERI Review, Progress Report

on Neutron Scattering Research (April 1, 2001 – March 31,

2002), edited by S. Katano, S. Koizumi, M. Matsuda (2002),

in press.

Jeng, U.-S., Lin, T.-L., Wang, L. Y., Chiang, L. Y., Ho, D. L., Han, C.

C., “SANS Structural Characterization of Fullerenol-Derived

Star Polymers In Solutions,” Appl. Phys. A 74, S487 (2002).

Jeon, H. S., Dixit, P. S., Yim, H., Kent, M. S., Shin, S., Satija, S.

“Interfacial Structure and Properties in Polystyrene/Epoxy

Bilayer Films,” J. Polym. Sci. Pol. Phys. 40 (23), 2653 (2002).

Jones, C. Y., Marshall, S. L., Chakoumakos, B. C., Rawn, C. J.,

Ishii, Y., “Structure and Thermal Expansivity of

Tetrahydrofuran Deuterate Determined by Neutron Powder

Diffraction,” J. Phys. Chem. B 107 (25), 6026 (2003).

Jones, R. L., Hu, T. J., Prabhu, V. M., Soles, C. L., Lin, E. K., Wu,

W. L., Goldfarb, D. L., Angelopoulos, M., “Form of

Deprotection in Chemically Amplified Resists,” in

Proceedings of the International Conference on

Characterization and Metrology for ULSI Technology, (March,

2003, Austin, TX), in press.

Jones, R. L., Hu, T. J., Prabhu, V. M., Soles, C. L., Lin, E. K., Wu,

W. L., Goldfarb, D. L., Trinque, B. C., Willson, C. G.,

“Deprotection Volume Characteristics and Line Edge

Morphology in Chemically Amplified Resists,” in Proceedings

of the SPIE: Advances in Resist Technology and Processing

XX, (March, 2003, Austin, TX), 5039 (2003), p. 1031.

Jones, R. L., Hu, T., Lin, E. K., Wu, W. L., Casa, D. M., Orji, N. G.,

Vorburger, T. V., Bolton, P. J., Barclay, G. G., “Sub-Nanometer

Wavelength Metrology of Lithographically Prepared

Structures: A Comparison of Neutron and X-ray Scattering,” in

Proceedings of the SPIE: Metrology, Inspection, and Process

Control for Microlithography XVII, (February, 2003, Santa

Clara, CA), in press.

Jones, R. L., Kumar, S. K., Grull, H., Han, C. C., Briber, R. M.,

Russell, T. P., “Experimental Phase Behavior of Ultrathin Film

Polymer Mixtures,” in press.

Jones, R. L., Prabhu, V. M., Goldfarb, D. L., Lin, E. K., Soles, C. L.,

Lenhart, J. L., Wu, W. L., Angelopoulos, M., “Correlation of

the Reaction Front with Roughness in Chemically Amplified

Photoresists,” in Symposia of the American Chemical Society,

(American Chemical Society, Washington, DC), in press.

Jones, R. L., Soles, C. L., Starr, F. W., Lin, E. K., Lenhart, J. L., Wu,

W. L., Goldfarb, D. L., Angelopolous, M., “Chain

Conformation in Ultrathin Polymer Films,” in Proceedings of

the SPIE: Advances in Resist Technology and Processing XIX,

(March, 2002, Santa Clara, CA) 4690 (2003), p. 342.

Jones, R. L., Starr, F. W., Soles, C. L., Lin, E. K., Lenhart, J. L., Wu,

W. L., Goldfarb, D., Angelopoulos, M., “Chain Conformation

in Ultrathin Polymer Resists,” in Proceedings of the SPIE

Conference, 4689 (2002).

Jones, T. D., Chappin, K. A., Bates, F. S., Annis, B. K., Hagaman,

E. W., Kim, M.-H., Wignall, G. D., Fan, W., Waymouth, R.,

“Effect of Tecticity on Coil Dimensions and Thermodynamics

Properties of Polypropylene,” Macromol. 35, 5061 (2002).

Kang, H. J., Dai, P., Lynn, J. W., Matsuura, M., Thompson, J. R.,

Zhang, S.-C., Argyriou, D. N., Onose, Y., Tokura, Y.,

“Antiferromagnetic Order as the Competing Ground State in

Electron Doped Nd1.85Ce0.15CuO4

,” Nature 423, 522 (2003).

Karen, P., Kjekshus, A., Huang, Q., Karen, V. L., Lynn, J. W.,

Rosov, N., Natali-Sora, I., Santoro, A., “Neutron Powder

Diffraction Study of Nuclear and Magnetic Structures of

Yba2Fe3O8+ù (-0.24 < ù < 0.11),” J. Solid State Chem., in

press.

Karim, A., Yurekli, K., Meredith, C., Amis, E., Krishnamoorti, R.,

“Combinational Methods for Polymer Materials Science:

Phase Behavior of Nanocomposite Blend Films,” Polym. Eng.

Sci. 42 (9), 1836 (2002).

Karlsson, E. B., Abdul-Redah, T., Udovic, T. J., Hjörvarsson, B.,

Chatzidimitriou-Dreismann, C. A., “Short-lived Proton

Entanglement in Yttrium Hydrides,” Appl. Phys. A 74, S1203

(2002).

Karunadasa, H., Huang, Q., Ueland, B. G., Schiffer, P., Cava R. J.,

“Ba2

LnSbO6 and Sr2LnSbO6 (Ln = Dy, Ho, Gd) Double

Perovskites: Lanthanides in the Geometrically Frustrating fcc

Lattice,” in Proceedings of the National Academy of Sciences of

the United States 100 (14), 8097 (2003).

Keller, T., Wagner, W., Allen, A., “Characterisation of Thermally

Sprayed Metallic NiCrAlY Deposits by Multiple Small-Angle

Scattering,” Appl. Phys. A 74, S975 (2002).
56

Kelly, R. W., Murphy, K. E., Becker, D. A., Mann, J. L.,

“Determination of Cr in Certified Reference Material HISS-1,

Marine Sediment, by Cold Plasma Isotope Dilution ICP-MS

and INAA: Comparison of Microwave Versus Closed (Carius)

Tube Digestion,” J. Anal. At. Spectrom. 18, 166 (2003).

Kent, M., “A Quantitative Study of Tethered Chains in Various

Solution Conditions Using Langmuir Diblock Copolymer

Monolayers,” Macromol., in press.

Kenzelmann, M., Chien, Y., Broholm, C., Reich, D. H., Qiu, Y.,

“Field Dependence of Solitons and Breathers in an

Antiferromagnetic S=1/2 Chain,” Phys. Rev. Lett., in press.

Kenzelmann, M., Xu, G., Zaliznyak, I. A., Broholm, C., DiTusa, J.

F., Aeppli, G., Ito, T., Oka, K., Takagi, H., “Structure of End

States for a Haldane Spin Chain,” Phys. Rev. Lett. 90 (8),

087202 (2003).

Kepa, H., Kutner-Pielaszek, J., Twardowski, A., Majkrzak, C. F.,

Story, T., Sadowski, J., Giebultowicz, T. M., “Polarized

Neutron Reflectometry Studies of GaMnAs/GaAs

Superlattices,” Appl. Phys. A 74, S1526 (2002).

Kepa, H., Majkrzak, C. F., Sipatov, A. Y., Giebultowicz, T. M.,

“Polarized Neutron Reflectometry Studies of Magnetic

Semiconductor Superlattices,” Physica B, in press.

Kepa, H., Springholz, G., Giebultowicz, T. M., Goldman, K. I.,

Majkrzak, C. F., Kacman, P., Blinowski, J., Holl, S., Krenn,

H., Bauer, G., “Magnetic Interactions in EuTe Epitaxial Layers

and EuTe/PbTe Superlattices,” Phys. Rev. B, in press.

Kepa, H., Van Khoi, L., Brown, C. M., Sawicki, M., Furdyna, J. K.,

Giebultowicz, T. M., “Probing Hole-Induced Ferromagnetic

Exchange in Magnetic Semiconductors by Inelastic Neutron

Spectroscopy,” Phys. Rev. Lett., in press.

Khalifah, P., Osborn, R., Huang, Q., Zandergen, H. W., Jin, R., Liu,

Y., Mandrus, D., Cava, R. J., “Orbital Ordering Transition in

La4

Ru2O10,” Science 297 (5590), 2237 (2002).

Khaykovich, B., Birgeneau, R. J., Chou, F. C., Erwin, R. W.,

Kastner, M. A., Lee, S.-H., Lee, Y. S., Smeibidl, P.,

Vorderwisch, P., Wakimoto, S., “Effect of a Magnetic Field on

Long-Range Magnetic Order in Stage-4 and Stage-6

Superconducting La2

CuO4+y,” Phys. Rev. B 67 (5), 054501

(2003).

Kidwell, C. B., Ondov, J. M. “Elemental Analysis of Sub-Hourly

Ambient Aerosol Collections,” Aersol. Sci. Technol., in press.

Kim, H., Huang, Q. Z., Lynn, J. W., Kauzlarich, S. M., “Neutron

Diffraction Study of the Ternary Metal Zintl Compound

Ca14MnSb11,” J. Solid. State. Chem. 168 (1), 162 (2002).

Kim, H.-C., Volksen, W., Miller, R. D., Huang, E., Yang, G., Briber,

R. M., Shin, K., Satija, S., “Neutron Reflectivity on

Nanoporous Poly(Methysilsesquioxane) Thin Films,” Chem.

Mater. 15 (3), 609 (2003).

Kline, S. R., Hammouda, B., “Corrective Refractive Optics Sharpens

Focus of SANS Instruments,” J. Res. Natl. Inst. Stand.

Technol., in press.

Kodibagkar, V. D., Browning, C. D., Udovic, T. J., Conradi, M. S.,

“Deuterium NMR Study of Structure and Motion in LuD3

,”

Phys. Rev. B 67, 174115 (2003).

Koga, T., Seo, Y. S., Zhang, Y., Shin, K., Kusano, K., Nishikawa, K.,

Rafailovich, M. H., Sokolov, J. C., Chu, B., Peiffer, D.,

Occiogrosso, R., Satija, S. K., “Density-Fluctuation-Induced

Swelling of Polymer Thin Films in Carbon Dioxide,” Phys.

Rev. Lett. 89 (12), 125506 (2002).

Koga, T., Seo, Y.-S., Hu, X., Shin, K., Zhang, Y., Rafailovich, M. H.,

Sokolov, J. C., Chu, B., Satija, S., “Dynamics of Polymer Thin

Films in Supercritical Carbon Dioxide,” Europhys. Lett. 60 (4),

559 (2002).

Koga, T., Seo, Y.-S., Shin, K., Zhang, Y., Rafailovich, M. H.,

Sokolov, J. C., Chu, B., Satija, S. K., “The Role of Elasticity in

the Anomalous Swelling of Polymer Thin Films in Density

Fluctuating Supercritical Fluids,” Macromol. 36, 5236 (2003).

Koga, T., Shin, K., Zhang, Y., Seo, Y.-S., Rafailovich, M. H.,

Sokolov, J., Chu, B., Satija, S. K., “Polymer Thin Films in

Supercritical CO2

,” in Proceedings of the ASR-2000, J. Phys.

Soc. Japan., in press.

Kreyssig, A., Stockert, O., Reznik, D., Woodward, F. M., Lynn,

J. W., Bitterlich, H., Souptel, D., Behr, G., Loewenhaupt, M.,

“Magnetic Excitations of RNi2

B2C Single Crystals with

R=Tb and Ho,” Physica C., in press.

Krishnamurthy, V. V., Bhandar, A. S., Piao, M., Zoto, I., Lane, A.

M., Nikles, D. E., Wiest, J. M., Mankey, G. J., Porcar, L.,

Glinka, C. J., “Shear and Magnetic Field Induced Ordering in

Magnetic Nanoparticles Dispersions from Small Angle

Neutron Scattering,” Phys. Rev. E 67 (5), 051406 (2003).

Krueger, S. K., Gregurick, S., Shi, Y., Wang, S., Wladkowski, B. D.,

Schwartz, F. P., “Entropic Nature of the Interaction Between

Promoter Bound CRP Mutants and RNA Polymerase,”

Biochemistry 42 (7), 1958 (2003).

Krueger, S. K., Gregurick, S., Zondlo, J., Eisenstein, E., “Interaction

of GroEL and GroES/GroES Complexes with a Non-Native

Subtilisin Variant: A Small-Angle Neutron Scattering Study,” J.

Struc. Biology 141, 240 (2003).

Kucera, J., Zeisler, R., “Low-Level Determination of Silicon in

Biological Materials Using Radiochemical Neutron Activation

Analysis,” J. Radioanal. Nucl. Chem., in press.

Kulkarni, A., Wang, Z., Nakamura, T., Sampath, S., Goland, A.,

Herman, H., Allen, J., Ilavsky, J., Long, G., Frahm, J.,

Steinbrech, R. W., “Comprehensive Microstructural

Characterization and Predictive Property Modeling of PlasmaSprayed Zirconia Coatings,” Acta Mater. 51 (9), 2457 (2003).

Kutteruf, M. R., Brown, C. M., Iwaki, L. K., Cambell, T. M.,

Korter, T. M., Heilweil, E. J., “Terahertz Spectroscopy of

Short-Chain Polypeptides,” Chem. Phys. Letts. 375 (3-4), 337

(2003).

Kuzmanovic, D. A., Elashvili, I., Wick, C., O’Connell, Krueger, S.,

“Spatial Distribution Analysis and Molecular Weight

Determination of Bacteriophage MS2 by Small Angle Neutron

Scattering and a Novel Concentration Determination Method,”

Structure, in press.

Lamaze, G. P., Chen-Mayer, H. H., Becker, D. A., Vereda, F.,

Goldner, R. B., Haas, T., Zerigian, P., “Cold Neutron Depth

Profiling of Lithium Battery Materials,” J. Power Sources 119,

680 (2003).

Lee, A. S., Butun, V., Vamvakaki, M., Armes, S. P., Pople, J. A.,

Gast, A. P., “Structure of pH-Dependent Block Copolymer

Micelles: Charge and Ionic Strength Dependence”, Macromol.

35 (22), 8540 (2002).
Publications

57

Lee, H. J., Lin, E. K., Bauer, B. J., Wu, W. L., Hwang, B. K., Gray,

W. D., “Characterization of Chemical-Vapor-Deposited Low-k

Thin Films Using X-Ray Porosimetry,” Appl. Phys. Lett. 82,

1084 (2003).

Lee, H. J., Soles, C. L., Liu, D. W., Bauer, B. J., Wu, W. L., “Pore

Size Distributions in Low-k Dielectric Thin Films from X-ray

Porosimetry,” Journal of Polymer Science Part B-Polymer

Physics 40, 2170-2177 (2002).

Lee, J. H., Balsara, N. P., Chakraborty, A. K., Krishnamoorti, R.,

Hammouda, B., “Thermodynamics and Phase Behavior of

Block Copolymer/Homopolymer Blends with Attractive and

Repulsive Interactions,” Macromol. 35 (20), 7748 (2002).

Lee, S.-H., Broholm, C., Ratcliff, W., Gasparovic, G., Huang, Q.,

Kim, T. H., Cheong, S. W., “Emergent Excitations in a

Geometrically Frustrated Magnet,” Nature, 418, 856 (2002).

Lefebvre, A. A., Lee, J. H., Balsara, N. P., Vaidyanathan, C.,

“Determination of Critical Length Scales and the Limit of

Metastability in Phase Separating Polymer Blends,” J. Chem.

Phys. 117, 9063 (2002).

Lefebvre, A. A., Lee, J. H., Balsara, N. P., Vaidyanathan, C.,

“Fluctuation Mediated Phase Separation in Polymer Blends

Near the Limit of Metastability,” J. Chem. Phys. 117, 9074

(2002).

Levin, I., Amos, T. G., Nino, J. C., Vanderah, T. A., Randall, C. A.,

Lanagan, M. T., “Structural Study of an Unusual Cubic

Pyrochlore Bi1.5Zn0.92Nb1.5O6.92,” J. Solid State Chem. 168 (1),

69 (2002).

Li, Z. G., Harlow, R. L., Foris, C. M., Li, H., Ma, P., Vickery, R. D.,

Maurin, M. B., Toby, B. H., “New Applications of Electron

Diffraction in the Pharmaceutical Industry: Polymorph

Determination by Using a Combination of Electron Diffraction

and Synchrotron X-ray Powder Diffraction Techniques,”

Microscopy and Microanalysis 8, 134 (2002).

Lin, E. K., Lee, H. J., Bauer, B. J., Wang, H., Wetzel, J. T., Wu, W.

L., “Structure and Property Characterization of Low-k

Dielectric Porous Thin Films Determined by X-ray

Reflectivity and Small-angle Neutron Scattering,” in Low

Dielectric Constant Materials for IC Applications, edited by P.

S. Ho, J. Leu, and W. W. Lee (Springer Publishing Inc), in

press.

Lin, E. K., Soles, C. L., Goldfarb, D. L., Trinque, B. C., Burns, S.

D., Jones, R. L., Lenhart, J. L., Angelopoulos, M., Willson, C.

G., Satija, S. K., Wu, W.-L., “Measurement of the Spatial

Evolution of the Deprotection Reaction Front with Nanometer

Resolution Using Neutron Reflectometry,” in Proceedings of

SPIE Conference (2002).

Lin, Y., Alexandridis, P., “Self-Assembly of an Amphiphilic Siloxane

Graft Copolymer in Water,” J. Phys. Chem. B 106, 10845

(2002).

Lin, Y., Alexandridis, P., “Small-Angle Neutron Scattering

Characterization of Micelles Formed by Poly(dimethylsiloxane)-graft-polyether Copolymers in Mixed Polar

Solvents,” J. Phys. Chem. B 106, 12124 (2002).

Lin, Y., Alexandridis, P., “Temperature-Dependent Adsorption of

Pluronic F127 Block Copolymers onto Carbon Black Particles

Dispersed in Aqueous Media,” J. Phys. Chem. B 106, 10834

(2002).

Lin, Z., Wu, C., Heller-Zeisler, S., Ondov, J. M., “Chemical Mass

Balance of Primary Aerosol Constituents in Baltimore Air,”

Atmos. Environ, in press.

Lindstrom, R. M., “An Improved Radiochemical Neutron Activation

Analysis Procedure for Trace Mercury,” J. Radioanal. Nucl.

Chem., in press.

Lindstrom, R. M., Blaauw, M., Unterweger, M., and Lucas, L. “The

Half-Lives of 24Na, 42K, and 198Au.,” J. of Radioanal. Nucl.

Chem., in press.

Ling, C. D., Granado, E., Neumeier, J. J., Lynn, J. W., Argyriou, D.

N., “Inhomogeneous Magnetism in La-Doped CaMnO3

: (II)

Phase Separation due to Lattice-Coupled Ferromagnetic

Interactions,” Phys. Rev. B, in press.

Ling, X. S., Park, S. R., Choi, S. M., Dender, D. C., Lynn, J. W.,

Reply to Comment on “Direct Observation on Superheating

and Supercooling of Vortex Matter Using Neutron

Diffraction,” Phys. Rev. Lett. 89 (25), 259702 (2002).

Lin-Gibson, S., Schmidt, G., Kim, H., Han, C. C., Hobbie, E. K.,

“Shear-Induced Mesostructure in Nanoplatelet-Polymer

Gels,” J. Chem. Phys., in press.

Liu, Q. T., Diamond, M. L., Gingrich, S. E., Ondov, J. M.,

Maciejczyk, P., Stern, G. A. “Accumulation of Metals, Trace

Elements and Semi-Volatile Organic Compounds in Films on

an Urban Impervious Surface,” Environ. Pollut. 122, 51

(2003).

Livingston, R. A., Bumrongjaroen, W., Neumann, D. A. “Inelastic

Neutron Scattering Measurements of Pozzolan Performance in

Portland Cement,” Nondestructive Characterization of

Materials XI, edited by R. E. Green, B. B. Djordjevic, and M.

P. Hentschel, (Springer, Berlin, Germany) 615 (2003).

Luzin, V., Brokmeier, H. G., “Attenuation Corrections in Neutron

Texture Experiment,” Mater. Sci. Forum 408, 191 (2002).

Luzin, V., Gnäupel-Herold, T., Prask, H. J., “Evaluation of Local

and Global Elastic Properties of Textured Polycrystals Means

of FEM,” Mater. Sci. Forum 408, 407 (2002).

Lynn, G., Dadmun, M. D., Lin, E. K., Wallace, W. E., Wu, W.,

“Neutron Reflectivity Studies on a Small Molecules Liquid

Crystal/Polymer Interface,” Liquid Crystal 29, 551 (2002).

Lynn, J. W., “Polaron Glass in Colossal Magnetoresistive Oxides

Researched,” J. Res. Natl. Inst. Stand. Technol. 107, 480

(2002).

Lynn, J. W., Huang, Q., Brown, C. M., Miller, V. L., Foo, M. L.,

Schaak, R. E., Jones, C. Y., Mackey, E. A., Cava, R. J.,

“Structure and Dynamics of Superconducting Nax

CoO2

Hydrate and Its Unhydrated Analog,” Phys. Rev. B, in press.

Maciejczyk, P. B., Zeisler, R., Hwang, J. S., Thurston, G. D., Chen,

L. C., “Characterization of Size-Fractioned World Trade

Center Dust and Estimation of Relative Dust Contribution to

Ambient Concentrations,” ACS Symposium Series, in press.

Mackay, M. E., Dao, T. T., Tuteja, A., Ho, D. L., Van Horn, B.,

Kim, H.-C., Hawker, C. J., “Nanoscale Effects Leading to

Non-Einstein-like Behavior – Reduction in Polymer Melt

Viscosity by the Addition of Nanometer-sized Particles,”

Nature Materials, in press.
58

Mackay, M. E., Hong, Y., Jeong, M., Tande, B. M., Wagner, N. J.,

Hong, S., Gido, S. P., Vestberg, R., Hawker, C. J.,

“Microphase Separation of Hybrid Dendron-Linear Diblock

Copolymers into Ordered Structures,” Macromol. 35, 8391

(2002).

Mackey, E. A., Oflaz, R. D., Epstein, M. S., Buehler, B., Porter, B.

J., Rowles, T., Wise, S. A., Becker, P. R., “Elemental

Composition of Liver and Kidney Tissues of Rough-Toothed

Dolphins (Steno Bredanensis),” Archives of Environ.

Contamination and Toxicology 44 (4), 523 (2003).

Majewski, J., Smith, G. S., Burgess, I., Zamlynny, V., Szymanski,

G., Lipkowski, J., Satija, S. K., “Neutron Reflectivity Studies

of Electric Field Driven Structural Transformations of

Surfactants,” Appl. Phys. A 74, S364 (2002).

Majkrzak, C. F., Berk, N. F., “Advances in Specular Neutron

Reflectometry,” J. Appl. Phys. A 74, S67 (2002).

Majkrzak, C. F., Berk, N. F., “Phase Sensitive Reflectometry and

the Unambiguous Determination of Scattering Length Density

Profiles,” Physica B, in press.

Majkrzak, C. F., Berk, N. F., Perez-Salas, U. A., “Phase-Sensitive

Neutron Reflectometry,” Langmuir, in press.

Manson, J. L., Bordallo, H. N., Lynn, J. W., Huang, Q., Feyerherm,

R., Loose, A., Chapon, L., Argyriou, N., “Magnetic Ordering

and Spin Excitations in Mn(dca)2

(pyz) [dca = N(CN)–

2

; pyz =

pyrazine],” Appl. Phys. A 74, S722 (2002).

Marazano, B. J., Wagner, N. J., “Flow-Small Angle Neutron

Scattering Measurements of Colloidal Dispersion

Microstructure Through the Shear Thickening Transition,” J.

Chem. Phys. 117 (22), 10291 (2002).

Marshall, J. C., Cosgrove, T., Jack, K., Howe, A., “Small-angle

Neutron Scattering of Gelatin/Sodium Dodecyl Sulfate

Complexes at the Polystyrene/Water Interface,” Langmuir 18

(25), 9668 (2002).

Martinho, H., Granado, E., Moreno, N. O., Garcia, A., Toniani, I.,

Rettori, C., Neumeier, J. J., Oseroff, S. B., “Strong Charge

Carrier Effect on the Magnetic Coupling of La-doped

CaMnO3

,” Physica B, in press.

Martter, T. D., Foster, M. D., Yoo, T., Xu, S., Lizzaraga, G., Quirk,

R. P., Butler, P. D., “Nonuniversal Behavior of the

Thermodynamic Interaction Parameter in Blends of Star and

Linear Polybutadiene,” Macromol. 35 (26), 9763 (2002).

Mason, T. G., Lin, M. Y., “Time-Resolved Small Angle Neutron

Scattering Measurements of Asphaltene Nanoparticle

Aggregation Kinetics in Incompatible Crude Oil Mixtures,” J.

Chem. Phys. 119, 565 (2003).

Mason, T. G., Lin, M. Y., “Asphaltene Nanoparticle Aggregation in

Mixtures of Incompatible Crude Oils,” Phys. Rev. E 67,

050401(2003), in press.

Matejícek, J., Sampath, S., Gnäupel-Herold, T., Prask, H. J.,

“Residual Stress in Sprayed Ni+5% Al Coatings Determined

by Neutron Diffraction,” Appl. Phys. A 74, S1692 (2002).

McGuire, S. C., Samuel, M. J., Sulcer, J. D., Lamaze, G. P., ChenMayer, H. H., “Neutron Depth Profiling of Boron-Doped

Ni3

Al Coatings,” American Laboratory, in press.

McKinsey, D. N., Dzhosyuk, S. N., Golub, R., Habicht, K.,

Huffman, P. R., Mattoni, C. E. H., Yang, L., Doyle, J. M.,

“Detecting Ionizing Radiation in Liquid Helium Using

Wavelength Shifting Light Collection,” Nucl. Intrum. Meth. A,

in press.

McKinsey, D. N., Dzhosyuk, S. N., Huffman, P. R., Mattoni, C. E.

H., Yang, L., Doyle, J. M., Golub, R., Habicht, K., “The Time

Dependence of Liquid Helium Fluorescence,” Phys. Rev. A 67,

044005 (2003).

Meyer, A., Dimeo, R. M., Gehring, P. M., Neumann, D. A., “The

High-Flux Backscattering Spectrometer at the NIST Center for

Neutron Research,” Rev. Sci. Instrum. 74 (5), 2759 (2003).

Mildner, D. F. R., Chen-Mayer, H. H., Gibson, W. M., “Focusing

Neutrons with Tapered Capillary Optics,” J. Appl. Phys. 92,

6911 (2002).

Mildner, D. F. R., Chen-Mayer, H. H., Gibson, W. M., Schultz, A.

J., “A Monolithic Polycapillary Focusing Optic for

Polychromatic Neutron Diffraction Applications,” in

Proceedings of the SPIE Conference, “Advanced In Neutron

Scattering Instrumentation, edited by I. S. Anderson, B.

Guérard (July 2002, Seattle, WA) 4785, (2002), p. 43.

Mook, H. A., Dai, P., Hayden, S. M., Hiess, A., Lynn, J. W., Lee,

S.-H., Dogan F., “Magnetic Ordering in YBa2

Cu3O6+x

Superconductors,” Phys. Rev. B 66 (14), 144512 (2002).

Moyer, R. O., Toby, B. H., “Ca2IrD5- An Order-Disorder

Transition,” J. Alloys Comp., in press.

Mukherjee, S., Cohen, R. E., Gulseren, O., “Vacancy Formation

Enthalpy at High Pressure in Tantalum,” Phys. Rev. B, in

press.

Nair, S., Tsapatsis, M., “Infared Reflectance Measurements of

Zeolite Film Thickness, Refractive Index and Other

Characteristics,” Micro. Meso. Mater. 58, 81 (2003).

Nakatani, A. I., “Chain Dimensions in Polysilicate-Filled Poly

(Dimethyl Siloxane),” in Proceedings of the International

Journal of Thermophysics, 14th Symposium on

Thermophysical Properties, (Boulder, CO), in press.

Narehood, D. G., Grube, N., Dimeo, R. M., Brown, D. W., Sokol, P.

E., “Inelastic Neutron Scattering of H2

 in Xerogel,” J. Low.

Temp. Phys. 132 (3-4), 223 (2003).

Narehood, D. G., Pearce, J. V., Eklund, P. C., Sokol, P. E., Lechner,

R. E., Pieper, J., Copley, J. R. D., Cook, J. C., “Diffusion of

H2

 Adsorbed on Single Walled Carbon Nanotubes,” Phys. Rev.

B 67, 205409 (2003).

Natali-Sora, I., Santoro, A., Huang, Q., “Oxidation States of Fe in

YBa2Fe3O8 From a Bond Valence Analysis of the Structure,” J.

Solid State Chem., in press.

Noakes, D. R., Arrott, A. S., Belk, M. G., Deevi, S. C., Huang, Q.

Z., Lynn, J. W., Shull, R. D., Wu, D., “Incommensurate Spin

Density Waves in Iron Aluminides,” Phys. Rev. Lett., in

press.

Norman, B. R., Iyengar, G. V., “Further Applications of PreIrradiation Combustion and Neutron Activation Analysis

Technique for the Determination of Iodine in Food and

Environmental Reference Materials: Merits and Demerits,”

Fresen. J. Anal. Chem., in press.
Publications

59

O’Donovan, K. V., Borchers, J. A., Majkrzak, C. F., Hellwig, O.,

Fullerton, E. E., “Extracting Buried Twists With Polarized

Neutron Reflectometry,” Appl. Phys. Lett. A 74, S1544

(2002).

Olin, J. S., Blackman, M. J., Mitchem, J. E., Waselkov, G. A.,

“Compositional Analysis of Glazed Earthenwares from

Eighteenth-Century Sites on the Northern Gulf Coast,” J.

Hist. Arch. 36 (1), 79 (2002).

Olin, J. S., Blackman, M. J., Waselkov, G., “Databases for the

Analysis of European Ceramics in American Archaeology,” in

Patterns and Process: A Festschrift in Honor of Dr. Edward V.

Sayre, Edited by Lambertus van Zelst, (Smithsonian Center

for Materials Research and Education, Suitland, Maryland)

p. 65.

Ondov, J. M., Caffrey, P. F., Suarez, A. E., Borgoul, P. V., Holsen,

T., Paode, R. D., Sofuoglu, S. C., Sivadechathep, J., Lu, J.,

Kelly, M. J., Church, T., Scudlark, J., “Atmospheric

Deposition of Trace Elements to Lake Michigan: Influence of

Urban and Industrial South Shore Sources,” Aerosol. Sci.

Technol., in press.

Otano-Rivera, W., Messier, R., Pilione, L. J., Santiago, J. J., Lamaze,

G. P., “Effect of Al Additions and AlN Interlayers on the

Stablization of cBN Sputtered Thin Films,” J. Diamond &

Rel. Matls., in press.

Ou-Yang, W.-C., Chen, H.-L., Ho, D. L., Tsao, C.-C., Yang, G., Peng,

K.-Y., Chen, S.-A., Han, C., “Solution Structure of

Electroluminescent Semiconducting Polymers MEH-PPV

Studied by SANS,” Phys. Rev. Lett., in press.

Park, S.-H., Gies, H., Toby, B. H., Parise, J. B., “Characterization of

a New Microporous Lithosilicate with ANA Topology,”

Chem. Mater. 14, 3187 (2002).

Paul, R. L., Chen-Mayer, H. H., Myneni, G. R., “Determination of

Hydrogen in Niobium by Cold Neutron Prompt Gamma-ray

Activation Analysis and Neutron Incoherent Scattering,” in

Hydrogen in Materials and Vacuum Systems, edited by G. R.

Myneni, S. Chattopadhyay (American Institute of Physics)

AIP Conference Proceedings 671 (Melville, NY 2003) p. 151.

Paul, R. L., Simons, D. S., “Calibration of Phosphorus Implantation

Dose in Silicon by Radiochemical Neutron Activation

Analysis,” in: Silicon Front-End Junction Formation

Technologies, MRS Symposium Proceedings, edited by D. F.,

Downey, M. E. Law, A. Claverie, M.J. Rendon, Matls. Res.

Soc., 717 (Warrendale, PA, 2002), p. 291.

Paul, R. L., Simons, D. S., “Radiochemical Neutron Activation

Analysis for Certification of Ion-Implanted Phosphorus in

Silicon,” Anal. Chem., in press.

Perez-Salas, U., Briber, R. M., Rafailovich, M. H., Sokolov, J.,

“Interfacial Fracture Toughness Between Glassy Polymer

Networks,” J. of Polym. Sci. Part B: Poly. Phys. 41 (16),

(2003).

Perez-Salas, U., Faucher, K. M., Majkrzak, C. F., Berk, N. F.,

Chaikof, E. L., Krueger, S., “Characterization of a Biomimetic

Polymeric Lipid Bilayer by Phase Sensitive Neutron

Reflectometry,” Langmuir, in press.

Perez-Salas, U., Briber, R. M., Hamilton, W. A., Rafailovich, M. H.,

Sokolov, J., Nasser, L., “Polystyrene Network-Network

Interdiffusion,” Macromol. 35 (17), 6638 (2002).

Phair, J. W., Schulz, J. C., Aldridge, L. P., Smith, J. D., “Small-Angle

Neutron Scattering (SANS) and Rheological Characterization

of AluminosilicateHydrogels,” J. Am. Cer. Soc., in press.

Phair, J. W., Schulz, J. C., Bertram, W. K., Aldridge, L. P.,

VanDeventer, J. S. J., “Investigation of the Microstructure of

Alkali Activated Cements by Neutron Scattering,” Cem. Conc.

Res., in press.

Popov, G., Lobanov, M. V, Tsiper, E., Greenblatt, M., Caspi, E. N.,

Lynn, J. W., “Neutron Diffraction Study of the Sr2

MnReO6

Double Perovskite,” J. Phys. C, in press.

Porcar, L., Hamilton, W. A., Butler, P. D., Warr, G. G., “Scaling of

Membrane Phase Dynamics,” NCNR Highlights, 30 (2002).

Porcar, L., Hamilton, W. A., Butler, P. D., Warr, G. G., “Scaling of

Shear-Induced Transformations in Membrane Phases,” Phys.

Rev. Lett. 89, 168301 (2002).

Porcar, L., Hamilton, W. A., Butler, P. D., Warr, G. G., “Scaling of

Structural and Rheological Response of L3 Sponge Phases in

the “Sweetened” Cetylpyridinium-Hexanol/dextrose-brine

System,” Langmuir, in press.

Prabhu, V. M., Jones, R. L., Lin, E. K., Soles, C. L., Wu, W. L.,

Goldfarb, D. L., Angelopoulos, M., “Polyelectrolyte Effects

in Model Photoresist Developer Solutions: Roles of Base

Concentration and Added Salts,” in Proceedings of the SPIE,

Advances in Resist Technology and Processing XX 5039

(February, 2003, Santa Clara, CA), p. 404.

Prabhu, V. M., Jones, R. L., Lin, E. K., Wu, W. L., “Polyelectrolyte

Effects in Model Photoresist Developer Solutions,” J. of

Vacuum Sci. Tech. B 21, 1403 (2003).

Prask, H. J., Gnäupel-Herold, T., Luzin, V., Fisher, J. W., Cheng X.,

Roy, S., “Residual Stress Modification and Fatigue Life

Enhancement,” in Trends in Welding Research, edited by S. A.

David et al. (ASM International, Materials Park, OH, 2003),

p. 897.

Prask, H. J., Gnäupel-Herold, T., Fisher, J. W., Cheng, X., Stuart, J.

T., “Residual Stress Modification by Means of Ultrasonic

Impact Treatment,” in Proceedings of the SEM Annual

Conference on Experimental and Applied Mechanics, (June,

2001, Porland, Oregon), p. 551.

Pugh, D. V., Dursun, A., Corcoran, S. G., “Formation of Nanoporous

Platinum by Selective Dissolution of Cu From Cu0.75 Pt0.25,” J.

Mater. Res. 18 (1), 216 (2003).

Qiu, Y., Broholm, C., Ishiwata, S., Azuma, M., Takano, M., Bewley,

R., Buyers, W. J. L., “Spin Trimer Antiferromagnetism in

La4

Cu3MoO12,” Phys. Rev. B, in press.

Radlinski, A. P., Ioannidis, M. A., Hinde, A. L., Hainbuchner, M.,

Baron, M., Rauch, H., Kline, S. R., “Angstrom to Millimeter

Characterization of Sedimentary Rock Microstructure,” Phys.

Rev. Lett., in press.

Raphael, M. P., Ravel, B., Huang, Q., Willard, M. A., Cheng, S. F.,

Das, B. N., Stroud, R. M., Bussmann, K. M., Claassen, J. H.,

Harris, V. G., “Presence of Antisite Disorder and its

Characterization in the Predicted Half-Metal Co2

MnSi,”

Phys. Rev. B 66, 104429 (2002).

Rathgeber, S., Gast, A. P., Hedrick, J. L., “Structural Properties of

Star-Like Dendrimers in Solution,” Appl. Phys. A 74, S396

(2002).
60

Rawn, C. J., Rondinone, A. J., Chakoumakos, B. C., Marshall, S. L.,

Stern, L. A., Circone, S., Kirby, S. H., Jones, C. Y., Toby, B.

H., Ishii, M., “Neutron Powder Diffraction Studies as a

Function of Temperature of Structure II Hydrate Formed a

Methane + Ethane Gas Mixture,” in Proceedings of the 4th

International Conference on Gas Hydrates, (Yokohama,

Japan, 2002), in press.

Reynolds, A. P., Tang, W., Gnäupel-Herold, T., Prask, H.,

“Structure, Properties, and Residual Stress of 304L Stainless

Steel Friction Stir Welds,” Scripta Mater. 48 (9), 1289 (2003).

Riseman, T. M., Forgan, E. M., “Maximum Entropy ìSR Analysis

I: Planting the Kernel,” in Conference Proceedings, 9th

International Conference on Muon Spin Rotation/Relaxation/

Resonance, Physica B 326, 226 (2003).

Riseman, T. M., Forgan, E. M., “Maximum Entropy ìSR Analysis

II: The Search For Truthful Errors,” in Conference

Proceedings, 9th International Conference on Muon Spin

Rotation/Relaxation/Resonance, Physica B 326, 230 (2003).

Riseman, T. M., Forgan, E. M., “Maximum Entropy μSR Analysis

III: Automatic Selection of the Default Level and Looseness

Factor,” in Conference Proceedings, 9th International

Conference on Muon Spin Rotation/Relaxation/Resonance,

Physica B 326, 234 (2003).

Rondinone, A. J.; Jones ,C. Y.; Marshall, S. L.; Chakoumakos, B. C.;

Rawn, C. J.; Lara-Curzio, E. “A Sapphire Cell for HighPressure, Low-Temperature Neutron Scattering Experiments

on Gas Hydrates,” Can. J. Chem., 81 (1-2), 381 (2003).

Rothman, M. S., Blackman, M. J., “Late Fifth Millennium and

Earliest Fourth Millennium B. C. Exchange Systems in

Northern Mesopotamia: Chemical Characterization of Sprig

and Impressed Ware,” Al-Rafidan XXIV, 1 (2003).

Rush, J. J., Udovic, T. J., “Modern Neutron Methods for the Study

of Hydrogen in Materials,” in EPD Congress 2002 and

Fundamentals of Advanced Materials for Energy Conversion,

edited by P. R. Taylor, D. Chandra, and R. G. Bautista, (The

Minerals, Metals & Materials Society, Warrendale, PA, 2002)

p. 161.

Ruzette, A.-V. G., Mayes, A. M., Pollard, M., Russell, T. P.,

Hammouda, B., “Pressure Effects on the Phase Behavior of

Styrene/n-Alkyl Methacrylate Block Copolymers,”

Macromol. 36 (9), 3351 (2003).

Sackett, D. L., Chernomordik, V., Krueger, S., Nossal, R., “Use of

Small-Angle Neutron Scattering To Study Tubulin Polymers,”

Biomacro. 4 (2), 461 (2003).

Saiz, L., Bandyopadhyay, S., Klein, M. L., “Effect of the Pore

Region of a Transmembrane Ion-Channel on the Physical

Properties of a Simple Membrane,” in Proceedings of the

National Academy of Science USA, in press.

Saiz, L., Bandyopadhyay, S., Klein, M. L., “Towards an

Understanding of Complex Biological Membranes from

Atomistic Molecular Dynamics Simulations,” Bioscience

Reports 22, 151 (2002).

Saiz, L., Klein, M. L., “Computer Simulation Studies of Model

Biological Membranes,” Acc. Chem. Res. 35, 482 (2002).

Saiz, L., Klein, M. L., “Electrostatic Interaction in a Neutral Model

Phospholipid Bi-Layer by Molecular Dynamics Simulations,”

J. Chem Phys. 116, 3052 (2002).

Saiz, L., Koubi, L., Tarek, M., Scharf, D., Klein, M. L., “Influence

of Anesthetic and Non-Immobilizer Molecules on the Physical

Properties of a Polyunsaturated Lipid Bilayer,” J. Phys.

Chem., in press.

Sato, T. J., Lee, S.-H., Katsufuji, T., Masaki, M., Park, S., Copley,

J. R. D., Takagi, H., “Unconventional Spin Fluctuations in the

Hexagonal Antiferromagnet YMnO3

,” Phys. Rev. B 68,

014432 (2003).

Sayer, E. V., Yener, A. K., Joel, E. C., Blackman, M. J., Özbal, H.,

“Stable Lead Isotope Studies of Black Sea Anatolian Ore

Sources and Related Bronze Age and Phrygian Artifacts From

Nearby Archaeological Sites Appendix: New Central Taurus

Ore Data,” Archaeometry, in press.

Schneider, J. P., Pochan, D. J., Ozbas, B., Rajagopal, K., Pakstis, L.

M., Gill, J. “Responsive Hydrogels From the Intramolecular

Folding and Self-Assembly of a Designed Peptide,” J. Am.

Chem. Soc. 124, 15030 (2002).

Schoen, K., Kaiser, H., Werner, S. A., Arif, M., Huffman, P. R.,

Jacobson, D. L., Black, T. C., Snow, W. M., Lamoreaux, S. K.,

“Precision Neutron Interferometric Measurements of the n-H

and n-D Coherent Neutron Scattering Lengths,” Phys. Rev. C

67, 044005 (2003).

Schubert, B. A., Kaler, E. W., Wagner, N. J., “The Microstructure

and Rheology of Mixed Cationic/anionic Wormlike Micelles,”

Langmuir 19 (10), 4079 (2003).

Sen, P., Gulseren, O., Yildirim, T., Batra, I. P., Ciraci, S., “Pentagonal

Nanowires: A First-Principles Study of Atomic and Electronic

Structure,” Phys. Rev. B 65, 235433 (2002).

Shah, S. A., Ramakrishnan, S., Chen, Y. L., Schweizer, K. S.,

Zukoski, C. F., “Scattering Structures of Colloid-Polymer

Suspensions and Gels,” Langmuir 19 (12), 5128 (2003).

Shapiro, S. M., Bao, W., Raymond, S., Lee, S. H., Motoya, K.,

“Observation of Linear Spin Wave Dispersion in Re-Entrant

Spin Glass Fe0.7Al0.3” Appl. Phys. A 74, S859 (2002).

Shin, K., Koga, T., Zhang, Y., Seo, Y., Occhiogrosso, R., Rafailovich,

M. H., Sokolov, J. C., Chu, B., Satija, S. K., “Anomalous

Carbon Dioxide-Induced Swelling of Polymer Thin Films at

Gas-Supercritical Transition,” J. Am. Chem. Soc., in press.

Shirane, G., Gehring, P. M., “Structure and Dynamics of the

Ferroelectric Relaxors Pb(Mg1/3Nb2/3)O3

 and

Pb(Zn1/3Nb2/3)O3

,” in Proceedings of the 104th Annual Meeting

of the American Ceramics Society,” Ceramic Transactions 136,

17 (2003).

Silas, J. A., Kaler, E. W., “Effect of Multiple Scattering on SANS

Spectra from Bicontinuous Microemulsions”, J. Coll. Interface

Sci., 257 (2), 291 (2003).

Simmons, B., Agarwal, V., McPherson, G., Arijit Bose, J., “A Small

Angle Neutron Scattering Study of Mixed AOT + Lecithin

Reverse Micelles,” Langmuir 18, 8345 (2002).

Sitepu, H., Schmahl, W. W., Stalick, J. K., “Correction of Intensities

for Preferred Orientation in Neutron-Diffraction Data of NiTi

Shape-Memory Alloy Using the Generalized SphericalHarmonic Description,” Appl. Phys. A 74, S1719 (2002).

Skripov, A. V., Buzlukov, A. L., Kozhanov, V. N., Udovic, T. J.,

Huang, Q., “Hydrogen in Nb(V1-yCry)2 Laves-phase

Compounds: Neutron Diffraction and Nuclear Diffraction and

Nuclear Magnetic Resonance Studies,” J. Alloys. Compnds.,

359, 27 (2003).
Publications

61

Skripov, A. V., Cook, J. C., Udovic, T. J., Gonzalez, M.,

Hempelmann, R., Kozhanov, V. N., “Quasielastic Neutron

Scattering Study of Hydrogen Motion in C15-type YMn2

Hx,”

J. Phys.: Condens. Matter 15, 3555 (2003).

Smee, S. A., Orndorff, J. D., Scharfstein, G. A., Qiu, Y., Brand, P. C.,

Broholm, C. L., Anand, D. K., “MACS Low-Background

Doubly Focusing Neutron Monochromator,” Appl. Phys. A

74, S255 (2002).

Soles, C. L., Douglas, J. F., Lin, E. K., Lenhart, J. L., Jones, R. L.,

Wu, W.-L., “Incoherent Neutron Scattering and the Dynamics

of Thin Film Photoresist Polymers,” J. Appl. Phys. 93 (4),

1978 (2003).

Soles, C. L., Douglas, J. F., Wu, W.-L., Dimeo, R. M., “Incoherent

Neutron Scattering as a Probe of the Dynamics in Molecularly

Thin Polymer Films,” Macromol. 36 (2), 373 (2003).

Soles, C. L., Douglas, J. F., Wu, W.-L., Peng, H., Gidley, D. W., “A

Broad Perspective on the Dynamics of Highly Confined

Polymer Films,” in Proceedings of the MRS Conference 710,

DD3.7.1 (2002).

Spiecker, P. M., Gawrys, K. L., Kilpatrick, P. K., “Aggregation and

Solubility Behavior of Asphaltenes and Their Subfractions,” J.

Colloid Interf. Sci., in press.

Spiecker, P. M., Gawrys, K. L., Trail, C. B., Kilpatrick, P. K.,

“Effects of Petroleum Resins on Asphaltene Aggregation and

Water-in-Oil Emulsion Formation,” Colloids and Surfaces A

220, 9 (2003).

Starr, F. W., Sastry, S., Douglas, J. F., Glotzer, S. C., “What Do We

Learn from the Local Geometry of Glass-Forming Liquids?,”

Physical Review Letters 89, 5501 (2002).

Stellbrink, J., Allgaier, J., Wilner, L., Richter, D., Slawecki, T.,

Fetters, “Real Time SANS Study on Head Group SelfAssembly for Lithium Based Anionic Polymerizations,”

Polymer 43 (25), 7101 (2002).

Stock, C., Birgeneau, R. J., Wakimoto, J. S., Gardner, J. S., Chen,

W., Ye, Z.-G., Shirane, G., “Universal Static and Dynamic

Properties of the Structural Transitions in Pb(Zn1/3Nb2/3)O3

,”

Phys. Rev. B, in press.

Stone, M. B., Reich, D. H., Broholm, C., Lefmann, K., Rischel, C.,

Landee, C. P., Turnbull, M. M., “Extended Quantum Critical

Phase in a Magnetized Spin-1/2 Antiferromagnetic Chain,”

Phys. Rev. Lett. 91, 037205 (2003).

Stone, M. B., Rittner, J., Chen, Y., Yardimci, H., Reich, D. H.,

Broholm, C., Ferraris, D. V., Lectka, T., “Frustrated ThreeDimensional Quantum Spin Liquid in CuHpCl,” Phys. Rev. B

65, 064423 (2002).

Suarez, A. E., Ondov, J. M., “Atmospheric Deposition of Trace

Elements to the Chesapeake Bay: Influence of Urban and

Industrial Sources in Baltimore,” Environ. Sci. Tech., in press.

Suarez, A. E., Ondov, J. M., “Contributions of Some CytokineActive Metals from Coal and Oil Fired Power Plants,” Energy

and Fuels 16, 562 (2002).

Sung, L., Karim, A., Douglas, J. F., Han, C. C., “Modification of

Thin Film Phase Separation by a Surfactant,” Macromol., in

press.

Tang, F., Gnäupel-Herold, T., Prask, H. J., Anderson, I. E.,

“Neutron Diffraction Study of Residual Stresses in Al/AlCuFe

Composites,” in Advance in Powder Metallurgy & Particulate

Materials 2003, (International Conference on Powder

Metallurgy & Particulate Materials, June 8-12, 2003, Las

Vegas, Nevada, sponsored by the MPIF/APMI), in press.

Tang, F., Gnäupel-Herold, T., Prask, H. J., Anderson, I. E.,

“Neutron Diffraction Measurement on Residual Stresses and

Stress Partitioning in Al/AlCuFe Composites,” Matl. Sci.

Eng., in press.

Tang, F., Gnäupel-Herold, T., Prask, H. J., Anderson, I. E., “Pure Al

Matrix Composites Produced by Vacuum Hot Pressing:

Tensile Properties and Strengthening Mechanisms,” Metall.

Trans. A., in press.

Tarek, M., Neumann, D. A., Tobias, D. J., “Characterization of Subnanosecond Dynamics of the Molten Globule State of αLactalbumin using Quasielastic Neutron Scattering and

Molecular Dynamics Simulations,” Chem. Phys. 292, 435

(2003).

Tarek, M., Tobias, D. J., “Single Particle and Collective Dynamics

of Protein Hydration Water: A Molecular Dynamics Study,”

Phys. Rev. Lett. 89 (27), 275501 (2002).

Tennant, D. A., Broholm, C., Reich, D. H., Nagler, E., Granroth, G.

E., Barnes, T., Damle, K., Xu, G., Chen, Y., Sales, B. C.,

“Neutron Scattering Study of Two-Magnon States in the

Quantum Magnet Copper Nitrate,” Phys. Rev. B 67 (5),

054414 (2003).

Terry, J. S., Heller-Zeisler, S., Ondov, J. M., “Behavior of Three

Atmospheric Tracer Materials in a Pilot-Scale Coal

Combuster,” J. Radio. Analyt. Nuc. Chem. 251, 205 (2002).

Thornton, J., McMahon, P. J., Allman, B. E., Murphy, J. E.,

Nugent, K. A., Jacobson, D. L., Arif, M., Werner, S. A., “The

Detection and Sizing of Flaws in Components from the Hotend of Gas Turbines Using Phase-Contrast Radiography With

Neutrons: a Feasibility Study,” NDT & E International 36 (5),

289 (2003).

Toby, B. H., “A Program for Viewing and Editing CIF’s,” J. Appl.

Crystall., in press.

Toby, B. H., “Inspecting Rietveld Fits from pdCIF: pdCIFplot,” J.

Appl. Crystall., in press.

Toby, B. H., “The Classification of Powder Diffraction Data,”

International Tables for Crystallography, in press.

Toby, B. H., Von, Dreele, R. B., Larson, A. C., “Reporting of

Rietveld Results Using pdCIF: GSAS2CIF,” J. Appl.

Crystall., in press.

Toney, M. F., Rubin, K. A., Choi, S.–M., Glinka, C. J., “Small Angle

Neutron Scattering Measurements of Magnetic Cluster Sizes

in Magnetic Recording Disks,” Appl. Phys. Lett., in press.

Trouw, F., Borodin, O., Cook, J. C., Copley, J. R. D., Smith, G. D.,

“A Quasielastic Neutron Scattering Study of the Local

Dynamics of Poly(Ethylene Glycol) in Aqueous Solution,” J.

Phys. Chem., in press.

Tucker, R. T., Han, C. C., Dobrynin, A. V., Weiss, R. A., “SmallAngle Neutron Scattering Analysis of Blends with Very Strong

Intermolecular Interactions: Polyamide/ionomer Blends,”

Macromol. 36, 4404 (2003).
Udovic, T. J., Huang, Q., Rush, J. J., “A Neutron-PowderDiffraction Study of the Rare-Earth Deuteride Two-Phase

Region,” J. Alloys. Compnds. 356-357, 41 (2003).

Vajk, O. P., Greven, M., Mang, P. K., Lynn, J. W., “Neutron

Scattering, Magnetometry, and Quantum Monte Carlo Study

of the Randomly-Diluted Spin-1/2 Square-Lattice Heisenberg

Antiferromagnet,” Solid State Commun. 126 (1-2), 93 (2003).

Vaknin, D., Krüger, P., Lösche, M., “Anomalous X-Ray Reflectivity

Characterization of Ion Distribution at Biomimetic

Membranes,” Phys. Rev. Lett. 90, 178102 (2003).

Vogt, B. D., RamachandraRao, V. S., Gupta, R. R., Lavery, K. A.,

Francis, T. J., Russell, T. P., Watkins, J. J., “Phase Behavior of

Polystyrene-Block-Poly(n-alkyl Methacrylate)s Dilated with

Carbon Dioxide,” Macromol. 36 (11), 4029 (2003).

Wagner, N. J., Butera, R., “Shear Distortion and Relaxation

Dynamics of Colloidal Crystals Investigated by SANS Time

Slicing” Phys. Rev. E, in press.

Wakimoto, S., Birgeneau, R. J., Ichikawa, N., Kim, Y. J., Kojima, K.

M., Lee, S.-H., Tranquada, J. M., Uchida, S., Zimmermann,

M. V., “Effect of a Magnetic Field on the Spin-and ChargeDensity Wave Order on La1.45Nd0.4Sr0.15CuO4

,” Phys. Rev. B

67, 184419 (2003).

Wakimoto, S., Stock, C., Ye, Z.-G., Chen, W., Gehring, P. M.,

Shirane, G., “Mode-Coupling and Polar Nanoregions in the

Relaxor Ferroelectric Pb(Mg1/3Nb2/3)O3,” Phys. Rev. B 66 (22),

224102-1 (2002).

Wang, C. Y., Prabhu, V. M., Soles, C. L., Vogt, B. D., Wu, W. L., Lin,

E. K., Satija, S. K., “Interdiffusion in Polystyrene and EndFunctional Polystyrene Thin Films near a Solid Surface,” in

ACS Polymeric Materials: Science and Engineering, (New

York, NY, September 2003), in press.

Wang, H. Douglas, J. F., Satija, S. K., Composto, R. J., Han, C. C.,

“Early-Stage Compositional Segregation in Poymer Blend

Films,” Phys. Rev. E, 67 (6), 061801 (2003).

Wang, H., Nieh, M.-P., Hobbie, E. H., Glinka, C. J., Katsaras, J.,

“Kinetic Pathway of the Bilayered-Micelle to PerforatedLamellae Transition,” Phys. Rev. E 67, 060902 (2003).

Wang, H., Zhao, B., Wyslouzil, B., Streletzky K., “Small-Angle

Neutron Scattering of Soot Formed in Laminar Premixed

Ethylene Flames,” Proc. Combust. Inst. 29 2749, Part 2

(2003).

Wang, X. H., Dormidontova, E. E., Lodge, T. P., “The OrderDisorder Transition and the Disordered Micelle Regime for

Poly(ethylenepropylene-b-dimethylsiloxane) Spheres,”

Macromol. 35 (26), 9687 (2002).

Welp, K. A., Co, C., Wool, R. P., “Improved Reflectivity Fitting

Using SERF: Spreadsheet Environment Reflectivity Fitting,”

J. Neutron Res., in press.

Wesley, R., Armes, S. P., Thompson, L. J., “Block Copolymer

Interactions With Surfactants,” Langmuir, in press.

White, C. C., Wu, W. L., Pu, Y., Rafailovich, M., Sokolov, J.,

“Probe Segregation and T Determination of a Supported

Ultra-Thin Polystyrene Film Studied by X-ray and Neutron

Reflectivity, and SIMS,” Poly. Eng. Sci. 43, 1241 (2003).

Winn, B. L., Shapiro, S. M., Erwin, R., Schlagel, D. L., Lograsso, T.,

“Anomalous Phonon Damping in the High Temperature Shape

Memory Alloy Ti50Pd42Cr8

,” Appl. Phys. A 74, S1182 (2002).

Wiyatno, W., Fuller, G. G., Pople, J. A., Gast, A. P., Chen, Z. R.,

Waymouth, R. M., Myers, C. L., “Component Stress-strain

Behavior and Small-Angle Neutron Scattering Investigation of

Stereoblock Elastomeric Polypropylene”, Macromol. 36 (4),

1178 (2003).

Wiyatno, W., Pople, J. A., Gast, A. P., Waymouth, R., Fuller, G. G.,

“A Scattering Study of Elastomeric Polypropylene,” in press.

Woodward, P. M., Karen, P., “Mixed Valency in YBaFe2O5” Inorg.

Chem. 42, 1121-1129 (2003).

Wu, S. Y., Yang, C. C., Tsao, F. C., Li, W.-H., Lee, K. C., Lynn, J.

W., Yang, H. D., “Crystal Structure and Magnetic Ordering of

Mn and Ce in La0.7Ce0.15Ca0.15MnO3

,” J. Phys. Condens. Mat.

14 (47), 12585 (2002).

Xu, G., Aeppli, G., Broholm, C., DiTusa, J. F., Ito, T., Oka, K.,

Takagi, H., “Mesoscopic Phase Coherence in a Quantum Spin

Fluid,” Nature, in press.

Yamada, K., Kurahashi, K., Uefuji, Fujita, M., Park, S. I., Lee, S.-H.,

Endoh, Y., “Commensurate Spin Dynamics in the

Superconducting State of an Electron-Doped Cuprate

Superconductor,” Phys. Rev. Lett. 90 (13), 137004-1 (2003).

Yamaura, K., Huang, Q., Young, D. P., Arai, M., TakayamaMuromachi, E., “Electronic Properties of the Novel 4d

Metallic Oxide SrRhO3

,” Physica B 329, 820 (2003).

Yamaura, K., Huang, Q., Young, D. P., Noguchi, Y., TakayamaMuromachi, E., “Crystal Structure and Electronic and

Magnetic Properties of the Bilayered Rhodium Oxide

Sr3

Rh2O7,” Phys. Rev. B 66, 134431 (2002).

Yang, C. C., Wu, S. Y., Li, W.-H., Lee, K. C., Lynn, J. W., Liu, R. S.,

Shen, C. H., “Short-Range Magnetic Correlations in Spinel

LiMn2

O4,” Mater. Sci. Eng. B 95 (2), 162 (2002).

Yang, C. C., Wu, S. Y., Li, W.-H., Lee, K. C., Lynn, J. W., Wu, C.-G.,

“Magnetic Ordering of Fe in NCH5

-Intercalated Iron

Phosphate Fe(OH)PO4,” Physica B, 325 (1-4), 240 (2003).

Yang, G. Y., Briber, R. M., Huang, E., Rice, P. M., Volksen, W.,

Miller, R. D., “Morphological Development in Nanoporous

PMSSQ Films,” Chem. Mater., in press.

Yang, G. Y., Briber, R. M., Huang, E., Rice, P. M., Volksen, W.,

Miller, R. D., “Morphology of Nanoporous PMSSQ Films,”

Appl. Phys. Lett., in press.

Yang, L., Dzhosyuk, S. N., Gabrielse, J., Huffman, P. R., Mattoni,

C. E. H., Maxwell, S. E., McKinsey, D. N., Doyle, J. M.,

“Performance of a Large-Area Avalanche Photodiode at Low

Temperature for Scintillation Detection,” Nucl. Instrum.

Meth. A, in press.

Yildirim, T., “Lattice Dynamics of Solid Cubane within the QuasiHarmonic Approximation,” Solid State Comm. 124 (12), 449

(2002).

Yildirim, T., “The Surprising Superconductor of 2001,” Materials

Today 5 (4), 40 (2002).

Yildirim, T., Gulseren, O., “A Simple Theory of 40K Superconductivity in MgB2

; First-Principles Calculations of Tc, its

Dependence on Boron Mass and Pressure,” J. Phys. Chem.

Solids 63, 2201 (2002).

Yildirim, T., Gulseren, O., “First-Principles Zone-Center Theory of

Superconductivity in MgB2,” Appl. Phys. A 74, S945 (2002).

62
Publications

Yildirim, T., Harris, A. B., “Rotational and Vibrational Dynamics of

Interstitial Molecular Hydrogen,” Phys. Rev. B 66 (21),

214301 (2002).

Yildirm, T., Harris, A. B., “Quantum Dynamics of a Hydrogen

Molecule Confined in a Cylindrical Potential,” Phys. Rev. B

67, 245413 (2003).

Yim, H., Kent, M. S., Huber, D. L., Satija, S., Majewski, J., Smith,

G. S., “Conformation of End-Tethered PNIPAM Chains in

Water and in Acetone by Neutron Reflectivity,” Macromol. 36,

5244 (2003).

Yim, H., Kent, M. S., Matheson, A., Stevens, M. J., Ivkov, R.,

Satija, S. K., Majewski, J., Smith, G. S., “Adsorption of

Sodium Poly(styrenesulfonate) to the Air Surface of Water by

Neutron and X-ray Reflectivity and Surface Tension

Measurements: Polymer Concentration Dependence,”

Macromol. 35, 9737 (2002).

Young, S. K., Trevino, S. F., Beck Tan, N. C., “Small-Angle Neutron

Scattering Investigation of Structural Changes in Nafion

Membranes Induced by Swelling with Various Solvents,” J.

Poly. Sci. B: Poly. Phys. 40 (4), 387 (2002).

Young, S. K., Trevino, S. F., Beck Tan, N. C., Paul, R. L.,

“Utilization of Prompt-Neutron Activation Analysis in the

Evaluation of Nafion Membranes,” J. Poly. Sci. B: Poly. Phys.

41 (3), 1485 (2003).

Zaliznyak, I. A., “Continuum Spin Excitations in S=1 OneDimensional Antiferromagnet,” J. Appl. Phys. 91, 81221

(2002).

Zeder, M. A., Blackman, M. J., “Economy and Administration at

Banesh Malyan Exploring the Potential of Faunal and

Chemical Data for Understanding State Process,” in Yeki Bud,

Yeki Nabud: Essays on the Archaeology in Honor of William

M. Summer, edited by N. F. Miller, and K. Adbi (Cotsen

Institute of Archaeology, University of California at Los

Angeles) 48 (2003), p. 121.

Zeisler, R., “New NIST Sediment SRMs for Inorganic Analysis,” J.

of Radioanal. Nucl. Chem., in press.

Zeisler, R., Demiralp, R., “The Use of INAA in the Development of

Urban Air Particulate Matter SRMs,” J. Radioanal. Nucl.

Chem., in press.

Zeisler, R., Lindstrom, R. M., Greenberg, R. R. “Instrumental

Neutron Activation Analysis, a Valuable Link in Chemical

Metrology,” J. of Radioanal. Nucl. Chem., in press.

Zhang, Y., Ge, S., Tang, B., Rafailovich, M. H., Sokolov, J., Peiffer,

D., Li, Z., Lin, M., Dias, J. A., McElrath, K. O., Nguyen, D.,

Satija, S., Schwarz, S. A., “Interfacial Properties of Brominated

Isobutylene-co-p-Methylstyrene and Butadiene Polymers” in

Proceedings of the American Chemical Society 154th Rubber

Conference, in press.

Zhao, L., Robinson, L., Paul R. L., Greenberg, R. R., Miao, S.,

“Determination of Carbon, Nitrogen, and Phosphorus in

Cattail (Typha latifolia) by Cold Neutron Prompt Gamma

Activation Analysis,” J. of Radioanal. Nucl. Chem., in press.

Zheludev, A., Honda, Z., Broholm, C. L., Katsumata, K., Shapiro, S.

M., Kolezhuk, A., Park, S., Qiu, Y., “Massive Triplet

Excitations in a Magnetized Anisotropic Haldane Spin Chain,”

Phys. Rev. Lett., in press.

Zheludev, A., Maslov, S., Zaliznyak, I., Regnault, L. P., Masuda, T.,

Uchinokura, K., Erwin, R., Shirane, G., “Experimental

Evidence for Shekhtman-Entin-Wohlman-Aharony (SEA)

Interactions in Ba2

CuGe2O7,” Phys. Rev. B, in press.

Zhou, J., Deyhim, A., Krueger, S., Gregurick, S. K., “Small Angle

Neutron Scattering Studies of PNA and DNA Systems,”Abstr.

Pap. Am. Chem. Soc. 224, 262 (2002).

Zhou, C., Hobbie, E. K., Bauer, B. J., Han, C. C., “Equilibrium

Structure of Hydrogen-Bonded Polymer Blends,” J. Polym.

Sci. Part B: Poly. Phys., in press.

Zimmerman, M. V., “X-Ray Scattering Studies of Orbital and Charge

Ordering in Pr1-xCax

MnO3,” Phys. Rev. B, in press.

63
Instruments and Contacts

64

High resolution powder diffractometer (BT-1)

J. K. Stalick, (301) 975-6223, judith.stalick@nist.gov

B. H. Toby, (301) 975-4297, brian.toby@nist.gov

DARTS, Residual stress and texture

diffractometer (BT-8)

H. J. Prask, (301) 975-6226, hank@nist.gov

T. Gnäupel-Herold, (301) 975-5380, thomas.gnaeupelherold@nist.gov

30-m SANS instrument (NG-7)

C. J. Glinka, (301) 975-6242, cglinka@nist.gov

J. G. Barker, (301) 975-6732, john.barker@nist.gov

L. Porcar, (301) 975-5049, lionel.porcar@nist.gov

30-m SANS instrument (NG-3) (CHRNS)

B. Hammouda, (301) 975-3961, hammouda@nist.gov

S. R. Kline, (301) 975-6243, steven.kline@nist.gov

D. Ho, (301) 975-6422, derek.ho@nist.gov

8-m SANS instrument (NG-1)

D. Ho, (301) 975-6422, derek.ho@nist.gov

C. J. Glinka, (301) 975-6242, cglinka@nist.gov

J. G. Barker, (301) 975-6732, john.barker@nist.gov

USANS, Perfect SANS (BT-5) (CHRNS)

J. G. Barker, (301) 975-6732, john.barker@nist.gov

M.-H. Kim, (301) 975-6469, man-ho.kim@nist.gov

C. J. Glinka, (301) 975-6242, cglinka@nist.gov

Cold neutron reflectometer-vertical sample-polarized beam option

(NG-1)

C. F. Majkrzak, (301) 975-5251, cmajkrzak@nist.gov

J. A. Dura, (301) 975-6251, jdura@nist.gov

Advanced neutron diffractometer/reflectometer (NG-1):

M. Lösche, (301) 975-8128, loesche@nist.gov

TBA

Cold neutron reflectometer-horizontal sample (NG-7)

S. K. Satija, (301) 975-5250, satija@nist.gov

Young-Soo Seo, (301) 975-5660, ysseo@nist.gov

Triple-axis polarized-beam spectrometer (BT-2)

J. W. Lynn, (301) 975-6246, jeff.lynn@nist.gov

R. W. Erwin, (301) 975-6245, rerwin@nist.gov

Triple-axis fixed incident energy spectrometer (BT-7)

J. W. Lynn, (301) 975-6246, jeff.lynn@nist.gov

R. W. Erwin, (301) 975-6245, rerwin@nist.gov

Triple-axis spectrometer (BT-9)

R. W. Erwin, (301) 975-6245, rerwin@nist.gov

P. M. Gehring, (301) 975-3946, pgehring@nist.gov

SPINS, Spin-polarized triple-axis spectrometer (NG-5) (CHRNS)

S-H. Lee, (301) 975-4257, seung-hun.lee@nist.gov

S. Park, (301) 975-8369, sungil.park@nist.gov

FANS, Filter-analyzer neutron spectrometer (BT-4)

T. J. Udovic, (301) 975-6241, udovic@nist.gov

C. M. Brown, (301) 975-5134, craig.brown@nist.gov

FCS, Fermi-chopper time-of-flight spectrometer (NG-6)

C. M. Brown, (301) 975-5134, craig.brown@nist.gov

T. J. Udovic, (301) 975-6241, udovic@nist.gov

DCS, Disk-chopper time-of-flight spectrometer (NG-4) (CHRNS)

J. R. D. Copley, (301) 975-5133, jcopley@nist.gov

I. Peral, (301) 975-6235, inma@nist.gov

Y. Qiu., (301) 975-3274, yiming.qiu@nist.gov

HFBS, High-flux backscattering spectrometer (NG-2) (CHRNS)

Z. Chowdhuri, (301) 975-4404, zema.chowdhuri@nist.gov

E. Mamontov, (301) 975-6232, mamontov@nist.gov

NSE, Neutron spin echo spectrometer (NG-5) (CHRNS)

N. S. Rosov, (301) 975-5254, nrosov@nist.gov

D. Bossev, (301) 975-4662, dobrin.bossev@nist.gov

Prompt-gamma neutron activation analysis (NG-7)

R. M. Lindstrom, (301) 975-6281, dick.lindstrom@nist.gov

R. L. Paul, (301) 975-6287, rpaul@nist.gov

Other activation analysis facilities

R. R. Greenberg, (301) 975-6285, rgreenberg@nist.gov

Cold neutron depth profiling (NG-0)

G. Lamaze, (301) 975-6202, lamaze@nist.gov

Instrument development station (NG-0)

D. F. R. Mildner, (301) 975-6366, mildner@nist.gov

Neutron interferometer (NG-7)

M. Arif, (301) 975-6303, muhammad.arif@nist.gov

Fundamental neutron physics station (NG-6)

M. S. Dewey, (301) 975-4843, mdewey@nist.gov

Theory and modeling

N. F. Berk, (301) 975-6224, nfb@nist.gov

T. Yildirim, (301) 975-6228, taner@nist.gov

Sample environment

D. C. Dender, (301) 975-6225, dender@nist.gov
NIST Center for

Neutron Research

For copies of or information on this report, contact:

Ronald L. Cappelletti

(301) 975-6221

ron.cappelletti@nist.gov

For additional information on the facility, contact:

J. Michael Rowe

(301) 975-6210

mike.rowe@nist.gov

John J. Rush

(301) 975-6231

john.rush@nist.gov

To obtain guidelines for preparing proposals

to conduct research at the facility, contact:

William A. Kamitakahara

(301) 975-6878

william.kamitakahara@nist.gov

Location of all contacts:

NIST Center for Neutron Research

100 Bureau Drive, Mail Stop 8562

Gaithersburg, MD 20899-8562

Please visit our website for further information:

www.ncnr.nist.gov