A5058408815- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- High-pressure geophysics and materials
- NMR spectroscopy and applications
- Spectroscopy and Quantum Chemical Studies
- Advanced Chemical Physics Studies
- Surface Chemistry and Catalysis
- Advanced NMR Techniques and Applications
- Lipid Membrane Structure and Behavior
- Advanced Physical and Chemical Molecular Interactions
- Phase Equilibria and Thermodynamics
- Particle accelerators and beam dynamics
- Dendrimers and Hyperbranched Polymers
- Hydrocarbon exploration and reservoir analysis
- Enzyme Structure and Function
- nanoparticles nucleation surface interactions
- Graphene research and applications
- Nanopore and Nanochannel Transport Studies
- Polymer Surface Interaction Studies
- Analytical Chemistry and Chromatography
- Machine Learning in Materials Science
- Material Dynamics and Properties
- Protein Structure and Dynamics
Oak Ridge National Laboratory
2014-2024
Target (United States)
2022
Spallation Neutron Source
2000-2021
University of Missouri
1992-2017
Technical University of Denmark
2005-2017
NIST Center for Neutron Research
2010-2017
National Institute of Standards and Technology
2010-2017
University of Maryland, College Park
2017
Oak Ridge Associated Universities
2011
Institut Laue-Langevin
2007
We describe the design and current performance of backscattering silicon spectrometer (BASIS), a time-of-flight built at spallation neutron source (SNS) Oak Ridge National Laboratory (ORNL). BASIS is first silicon-based installed source. In addition to high intensity, it offers high-energy resolution about 3.5 μeV large variable energy transfer range. These ensure an excellent overlap with dynamic ranges accessible other inelastic spectrometers SNS.
Motion of water molecules in Aerosol OT [sodium bis(2-ethylhexyl) sulfosuccinate, AOT] reverse micelles with content w(0) ranging from 1 to 5 has been explored both experimentally through quasielastic neutron scattering (QENS) and molecular dynamics (MD) simulations. The experiments were performed at the energy resolution 85 microeV over momentum transfer (Q) range 0.36-2.53 A(-1) on samples which nonpolar phase (isooctane) AOT alkyl chains deuterated, thereby suppressing their contribution...
A combined small-angle neutron scattering (SANS) and X-ray (SAXS) study was conducted to investigate the structural characteristics of aqueous (D2O) solution generation 7 8 (G7 & G8) polyamidoamine (PAMAM) dendrimer as a function molecular protonation. consequent change in intramolecular conformation clearly quantified by detailed data analysis separating intermolecular correlations from contribution. Our results unambiguously reveal both an increase size continuous variation density profile...
Neutron diffraction patterns of dotriacontane ( $n{\ensuremath{-}\mathrm{C}}_{32}{\mathrm{D}}_{66}$) monolayers adsorbed on an exfoliated graphite substrate from a heptane $n{\ensuremath{-}\mathrm{C}}_{7}{\mathrm{D}}_{16}$) solution reveal striking differences in the molecular orientation, lattice constant, and coherence length those same monolayer gas phase. Neither $n{\ensuremath{-}\mathrm{C}}_{32}{\mathrm{D}}_{66}$ phase appears to be fully consistent with Groszek's model $n$-alkane...
Results of detailed structural studies, using elastic neutron scattering, the freezing liquid O2 and D2 in porous vycor glass are presented. The experimental studies have been complemented by computer simulations dynamics a Lennard-Jones narrow channels bounded molecular walls. Our results point to new simple physical interpretation confined geometries.
Small-angle neutron scattering (SANS) experiments were carried out to investigate the structure of aqueous (D(2)O) G4 PAMAM dendrimer solutions as a function molecular protonation and concentration. Our results indicate unambiguously that, although radius gyration R(G) remains nearly invariant, radial density profile rho(r) decreases in core with continuous increase protonation. This discovery also suggests that R(G), which is commonly adopted by numerous simulation experimental works...
The Multi-Grid detector technology has evolved from the proof-of-principle and characterisation stages. Here we report on performance of detector, MG.CNCS prototype, which been installed tested at Cold Neutron Chopper Spectrometer, CNCS SNS. This allowed a side-by-side comparison to 3He detectors an operational instrument. demonstrator active area 0.2 m2. It is specifically tailored specifications CNCS. was in June 2016 operated since then, collecting neutron scattering data parallel He-3 In...
BWAVES is an acronym for Broadband Wide-Angle VElocity Selector spectrometer, indicating that a novel WAVES (Wide-Angle Selector) device will be used to select the velocity/wavelength of detected neutrons after they are scattered by sample. We describe conceptual design BWAVES, time-of-flight broadband inverted-geometry neutron spectrometer Second Target Station at Spallation Neutron Source operated Oak Ridge National Laboratory. Being first inverted geometry where energy can chosen...
Quasielastic neutron scattering experiments and molecular dynamics (MD) simulations have been used to investigate diffusive motion near the melting transition of monolayers flexible rod-shaped molecules. The were conducted on butane hexane adsorbed an exfoliated graphite substrate. For butane, quasielastic broader than experimental energy resolution width 70 μeV appears abruptly at monolayer point Tm=116 K, whereas, for monolayer, it 20 K below (Tm=170 K). To facilitate comparison with...
Molecular dynamics (MD) simulations and neutron diffraction experiments have been performed on $n$-dotriacontane ( $n\ensuremath{-}{\mathrm{C}}_{32}{\mathrm{D}}_{66}$) monolayers adsorbed a graphite basal-plane surface. The show little change in the crystalline monolayer structure up to temperature of $\ensuremath{\sim}350\mathrm{K}$ above which large thermal expansion decrease coherence length occurs. MD provide evidence that this behavior is due phase transition intramolecular...
Research Article| January 01, 2006 Neutron Scattering and Diffraction Studies of Fluids Fluid-Solid Interactions David R. Cole; Cole Chemical Sciences Division Oak Ridge National Laboratory Ridge, Tennessee 37831-6110, U.S.A., e-mail: coledr@ornl.gov Search for other works by this author on: GSW Google Scholar Kenneth W. Herwig; Herwig Spallation Source 37831-6475, U.S.A. Eugene Mamontov; Mamontov John Z. Larese Department Chemistry University Knoxville, Tennessee, 37996, Reviews in...
Quasielastic neutron scattering has been used to investigate the single-particle dynamics of hydrogen fluoride across its entire liquid range at ambient pressure. For $T>230\text{ }\text{ }\mathrm{K}$, translational diffusion obeys celebrated Stokes-Einstein relation, in agreement with nuclear magnetic resonance studies. At lower temperatures, we find significant deviations from above behavior form a power law exponent $\ensuremath{\xi}=\ensuremath{-}0.71\ifmmode\pm\else\textpm\fi{}0.05$....
VENUS (Versatile Neutron Imaging Beam line at the Spallation Source) will be a world-class neutron-imaging instrument that uniquely utilize Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm μm). When completed, provide academia, industry government laboratories with opportunity advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology,...
Optimal enzyme activity depends on a number of factors, including structure and dynamics. The role is well recognized; however, the linkage between protein dynamics has given rise to contentious debate. We have developed an approach that uses aqueous mixture organic solvent control functionally relevant (without changing structure), which in turn modulates activity. Using this approach, we predicted hydride transfer reaction catalyzed by dihydrofolate reductase (DHFR) from Escherichia coli...
The structure of deuterated n-butane [${\mathrm{CD}}_{3}$(${\mathrm{CD}}_{2}$${)}_{2}$${\mathrm{CD}}_{3}$] adsorbed on the (0001) surfaces an exfoliated graphite substrate has been investigated by elastic neutron diffraction. aim this study was to elucidate effect steric properties, particularly rodlike shape molecule, both monolayer and multilayer film structure. Our principal findings are as follows: (1) solid a rectangular unit cell commensurate with lattice in one direction (2...
We present evidence from neutron diffraction measurements and molecular dynamics (MD) simulations of three different monolayer phases the intermediate-length alkanes tetracosane (n-C(24)H(50) denoted as C24) dotriacontane (n-C(32)H(66) C32) adsorbed on a graphite basal-plane surface. Our indicate that two films differ principally in transition temperatures between phases. At lowest temperatures, both C24 C32 form crystalline phase with rectangular-centered (RC) structure. The sublattices RC...
The single-particle small-angle scattering properties of five Platonic solids, including the tetrahedron, hexahedron, octahedron, dodecahedron and icosahedron, are systematically investigated. For each given geometry, Debye spatial autocorrelation function, pair distance distribution function intraparticle structure factor (form factor) calculated compared with corresponding a spherical reference system. From theoretical models, empirical relationship between dodecahedral icosahedral...
Abstract Water mobility in cancer cells could be a powerful parameter to predict the progression or remission of tumors. In present descriptive work, new insight into this concept was achieved by combining neutron scattering and thermal analyses. The results provide first step untangle role played water dynamics breast (MCF-7) after treatment with chemotherapy drug. By analyses, were probed as micrometric reservoirs bulk-like confined populations. Under perspective we showed that drug...
The translational and rotational motions of water dimethyl sulfoxide, [DMSO, (CH(3))(2)SO] have been investigated using quasi-elastic neutron scattering. Water-DMSO mixtures at five DMSO mole fractions, chi(DMSO), ranging from 0 to 0.75, were measured. Hydrogen-deuterium substitution was used extract independently the proton dynamics (d-DMSO-H(2)O), methyl (h-DMSO-D(2)O) obtain background corrections (d-DMSO-D(2)O). diffusion slows down significantly compared bulk all chi(DMSO)>0. time...
We have measured the inelastic neutron scattering from solid parahydrogen at molar volumes 23.2 to 17.0 ${\mathrm{cm}}^{3}$. observe peaks in differential cross section ${d}^{2}$\ensuremath{\sigma}/d\ensuremath{\Omega} dE corresponding internal molecular transitions ground excited rotational and vibrational states. From widths of these we determine center-of-mass translational energy per molecule using an underlying Gaussian momentum distribution for initial wave function. For 23.2, 21.3,...
A new spectrometer named BASIS has recently entered the general user program at Spallation Neutron Source. is an acronym for Backscattering Silicon Spectrometer. While there are several operational reactor-based spectrometers that utilize backscattering reflection from silicon single crystals, such as IN10 and IN16 [1] ILL, France; HFBS [2] NCNR, USA; SPHERES [3] FRM-II, JCNS, Germany, first built on a spallation neutron source. Conceptually, it similar to previously time-of-flight...