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Articles 1  18 of 18
FullText Articles in Physics
Posterminaries: After Nabarro, Alexander H. King
Posterminaries: After Nabarro, Alexander H. King
Alexander H. King
With the passing of Frank Nabarro in July of this year, we have lost one of the founding fathers of materials science. His name appears in many of the textbooks from which we train our students today, and also on the spines of several volumes on dislocation theory, including his classic monograph on the subject. He rightly stands among the gods of our field. Ninety years old at his death, he was a sprightly dancer at the frontiers of knowledge, right up to the end.
Posterminaries: The Scales Of Judgement, Alexander H. King
Posterminaries: The Scales Of Judgement, Alexander H. King
Alexander H. King
Materials scientists are generally wellversed in physics, and physics, above all, is a science of measurements. The first instinct of a physicist is to parse a problem in terms of its measurables in the dimensions of mass, length, and time, and it is the shifting of attention down the scale of length that particularly characterizes our present times as the Nano Age.
LowEnergy Nondipole Effects In Molecular Nitrogen ValenceShell Photoionization, Oliver Hemmers, Renaud Guillemin, D. Rolles, A. Wolska, Dennis W. Lindle, E. P. Kanter, B. Krassig, S. H. Southworth, R. Wehlitz, B. Zimmermann, V. Mckoy, P. W. Langhoff
LowEnergy Nondipole Effects In Molecular Nitrogen ValenceShell Photoionization, Oliver Hemmers, Renaud Guillemin, D. Rolles, A. Wolska, Dennis W. Lindle, E. P. Kanter, B. Krassig, S. H. Southworth, R. Wehlitz, B. Zimmermann, V. Mckoy, P. W. Langhoff
Environmental Studies Faculty Publications
Observations are reported for the first time of significant nondipole effects in the photoionization of the outervalence orbitals of diatomic molecules. Measured nondipole angulardistribution parameters for the 3σ_{g}, 1π_{u}, and 2σ_{u} shells of N_{2} exhibit spectral variations with incident photon energies from thresholds to ∼200 eV which are attributed via concomitant calculations to particular finalstate symmetry waves arising from (E1)⊗(M1,E2) radiationmatter interactions firstorder in photon momentum. Comparisons with previously reported Kedge studies in N_{2} verify linear scaling with photon momentum, accounting in part for the significantly enhanced nondipole behavior observed in innershell ionization ...
Femtosecond Nuclear Motion Of Hcl Probed By Resonant XRay Raman Scattering In The Cl 1s Region, Marc Simon, Loic Journel, Stephane Carniato, Richard Taieb, I. Minkov, Faris Gel'mukhanov, P. Salek, H. Agren, Renaud Guillemin, Wayne C. Stolte, A. C. Hudson, Dennis W. Lindle
Femtosecond Nuclear Motion Of Hcl Probed By Resonant XRay Raman Scattering In The Cl 1s Region, Marc Simon, Loic Journel, Stephane Carniato, Richard Taieb, I. Minkov, Faris Gel'mukhanov, P. Salek, H. Agren, Renaud Guillemin, Wayne C. Stolte, A. C. Hudson, Dennis W. Lindle
Chemistry and Biochemistry Faculty Publications
Femtosecond dynamics are observed by resonant xray Raman scattering (RXS) after excitation along the dissociative Cl 1s→6ơ* resonance of gasphase HCl. The short corehole lifetime results in a complete breakdown of the common nondispersive behavior of softxray transitions between parallel potentials. We evidence a general phenomenon of RXS in the hardxray region: a complete quenching of vibrational broadening. This opens up a unique opportunity for superhigh resolution xray spectroscopy beyond vibrational and lifetime limitations.
Posterminaries: Plain Text, Alexander H. King
Posterminaries: Plain Text, Alexander H. King
Alexander H. King
You just can’t win an argument with an English professor.
Thermal Effects On Domain Orientation Of Tetragonal Piezoelectrics Studied By In Situ XRay Diffraction, Wonyoung Chang, Alexander H. King, Keith J. Bowman
Thermal Effects On Domain Orientation Of Tetragonal Piezoelectrics Studied By In Situ XRay Diffraction, Wonyoung Chang, Alexander H. King, Keith J. Bowman
Alexander H. King
Thermal effects on domain orientation in tetragonal lead zirconate titanate (PZT) and lead titanate (PT) have been investigated by using in situ xray diffraction with an area detector. In the case of a soft PZT, it is found that the texture parameter called multiples of a random distribution (MRD) initially increases with temperature up to approximately 100 °C and then falls to unity at temperatures approaching the Curie temperature, whereas the MRD of hard PZT and PT initially undergoes a smaller increase or no change. The relationship between the mechanical strain energy and domain wall mobility with temperature is discussed.
Growth Of Ge Quantum Dots On Si(100)(2×1) By Pulsed Laser Deposition, M. S. Hegazy, H. E. ElsayedAli
Growth Of Ge Quantum Dots On Si(100)(2×1) By Pulsed Laser Deposition, M. S. Hegazy, H. E. ElsayedAli
Electrical & Computer Engineering Faculty Publications
Selfassembled germanium quantum dots (QDs) were grown on Si(100)(2×1) by pulsed laser deposition. In situ reflectionhigh energy electron diffraction (RHEED) and postdeposition atomic force microscopy are used to study the growth of the QDs. Several films of different thicknesses were grown at a substrate temperature of 400 °C using a Qswitched Nd:yttrium aluminum garnet laser (λ= 1064 nm, 40 ns pulse width, 23 J/cm ^{2} fluence, and 10 Hz repetition rate). At low film thicknesses, hut clusters that are faceted by different planes, depending on their height, are observed after the completion of the wetting ...
Dissolution, Reactor, And Environmental Behavior Of Zro2Mgo Inert Fuel Matrix, Kenneth Czerwinski
Dissolution, Reactor, And Environmental Behavior Of Zro2Mgo Inert Fuel Matrix, Kenneth Czerwinski
Fuels Campaign (TRP)
This project examines inert fuels containing ZrO_{2} and MgO as the inert matrix, with the relative amount of MgO varied from 30% to 70% in ZrO_{2}. Reactor physics calculations are used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10% of ^{239}Pu. Ceramics are synthesized and characterized based on the reactor physics results. The solubility of the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, are investigated in a manner to provide thermodynamic data necessary for modeling ...
SolutionBased Synthesis Of Nitride Fuels, Kenneth Czerwinski, Thomas Hartmann
SolutionBased Synthesis Of Nitride Fuels, Kenneth Czerwinski, Thomas Hartmann
Fuels Campaign (TRP)
A wide variety of fuel concepts are considered for advanced reactor technology including metals, metal oxides or metal nitrides as solid solutions or composite materials. Nitride fuels have appropriate properties for advanced fuels including high thermal conductivity, thermal stability, solidstate solubility of actinides, fissile metal density, and suitable neutronic properties. A drawback of nitride fuels involves their synthesis. A key parameter for preparing oxide fuels is the precipitation step in the solgel process. For nitride fuels, the current synthetic route is carbothermic reduction from the oxide to the nitride. This process step is based on solid phase reactions and for ...
InteractionInduced Dipole Moment Of The Ar–H_{2} Dimer: Dependence On The H_{2} Bond Length, Robert J. Hinde
InteractionInduced Dipole Moment Of The Ar–H2 Dimer: Dependence On The H2 Bond Length, Robert J. Hinde
Chemistry Publications and Other Works
We present ab initio calculations of the interactioninduced dipole moment of the Ar–H_{2} van der Waals dimer. The primary focus of our calculations is on the H_{2} bond length dependence of the dipole moment, which determines the intensities of both the collisioninduced H_{2} = 1 ← 0 fundamental band in gaseous Ar–H_{2} mixtures and the dopantinduced H_{2} = 1 ← 0 absorption feature in Ardoped solid H_{2} matrices. Our calculations employ large atomcentered basis sets, diffuse bond functions positioned between the two monomers, and a coupled cluster treatment of valence electron correlation; corevalence correlation effects appear ...
Population Size Bias In DescendantWeighted Diffusion Quantum Monte Carlo Simulations, G. Lee Warren, Robert J. Hinde
Population Size Bias In DescendantWeighted Diffusion Quantum Monte Carlo Simulations, G. Lee Warren, Robert J. Hinde
Chemistry Publications and Other Works
We consider the influence of population size on the accuracy of diffusion quantum Monte Carlo simulations that employ descendant weighting or forward walking techniques to compute expectation values of observables that do not commute with the Hamiltonian. We show that for a simple model system, the ddimensional isotropic harmonic oscillator, the population size must increase rapidly with d in order to ensure that the simulations produce accurate results. When the population size is too small, expectation values computed using descendantweighted diffusion quantum Monte Carlo simulations exhibit significant systematic biases.
Quantum Monte Carlo Calculations Applied To Magnetic Molecules , Larry Paul Engelhardt
Quantum Monte Carlo Calculations Applied To Magnetic Molecules , Larry Paul Engelhardt
Retrospective Theses and Dissertations
In this dissertation, we have implemented a quantum Monte Carlo (QMC) algorithm, and have used it to perform calculations for a variety of finite Heisenberg spin systems. A detailed description of the QMC method has been provided, which is followed by applications of the method to various systems. These applications begin with a detailed analysis of the (calculated) equilibrium magnetization and magnetic susceptibility for a number of Heisenberg Hamiltonians. In particular, we have studied the dependence of these quantities on intrinsic spin s, and have quantified the approach to the classical (s → infinity) limit. These results are not specific to ...
Tribological Properties Of Quasicrystals: Effect Of Aperiodic Versus Periodic Surface Order, Jeong Young Park, D. F. Ogletree, M. Salmeron, R. A. Ribeiro, Paul C. Canfield, Cynthia J. Jenks, Patricia A. Thiel
Tribological Properties Of Quasicrystals: Effect Of Aperiodic Versus Periodic Surface Order, Jeong Young Park, D. F. Ogletree, M. Salmeron, R. A. Ribeiro, Paul C. Canfield, Cynthia J. Jenks, Patricia A. Thiel
Chemistry Publications
We investigated the nanoscale tribological properties of a decagonal quasicrystal using a combination of atomic force microscopy and scanning tunneling microscopy in ultrahigh vacuum. This combination permitted a variety of in situ measurements, including atomicscale structure, friction and adhesion force, tipsample current, and topography. We found that thiolpassivated tips can be used for reproducible studies of the tipquasicrystal contact while nonpassivated probes adhere irreversibly to the clean quasicrystalline surface causing permanent modifications. The most remarkable results were obtained on the twofold surface of the AlNiCo decagonal quasicrystal where atoms are arranged periodically along the tenfold axis and aperiodically in the ...
Variational Path Integral Simulations Using Discretized Coordinates, Robert Hinde
Variational Path Integral Simulations Using Discretized Coordinates, Robert Hinde
Robert Hinde
We describe a variational path integral simulation algorithm for quantum Monte Carlo studies of manybody systems in which particles are restricted to occupy sites on a regular simple cubic lattice with lattice constant s, and discuss the algorithm’s potential computational benefits. Application of the algorithm to the weakly bound cluster Ne_{3} shows that accurate coordinatespace observables for this system can be computed using lattice constants as large as s = 0.2 a_{0}.
Dependence Of The H_{2}–H_{2} Interaction On The Monomer Bond Lengths: Steps Toward An Accurate Ab Initio Estimate, Robert Hinde
Dependence Of The H2–H2 Interaction On The Monomer Bond Lengths: Steps Toward An Accurate Ab Initio Estimate, Robert Hinde
Robert Hinde
We compute the vibrational coupling between two H_{2} molecules from ab initio quantum chemical calculations of the H_{2}–H_{2} potential carried out at the full configuration interaction level of theory using the atomcentered augccpVTZ basis set for hydrogen. We compare the full configuration interaction results with those obtained using two variants of coupled cluster theory and find that a fully iterative treatment of connected triples may be required to estimate the H_{2}–H_{2} vibrational coupling accurately using coupled cluster theory.
InteractionInduced Dipole Moment Of The Ar–H_{2} Dimer: Dependence On The H_{2} Bond Length, Robert J. Hinde
InteractionInduced Dipole Moment Of The Ar–H2 Dimer: Dependence On The H2 Bond Length, Robert J. Hinde
Robert Hinde
We present ab initio calculations of the interactioninduced dipole moment of the Ar–H_{2} van der Waals dimer. The primary focus of our calculations is on the H_{2} bond length dependence of the dipole moment, which determines the intensities of both the collisioninduced H_{2} = 1 ← 0 fundamental band in gaseous Ar–H_{2} mixtures and the dopantinduced H_{2} = 1 ← 0 absorption feature in Ardoped solid H_{2} matrices. Our calculations employ large atomcentered basis sets, diffuse bond functions positioned between the two monomers, and a coupled cluster treatment of valence electron correlation; corevalence correlation effects appear ...
Population Size Bias In DescendantWeighted Diffusion Quantum Monte Carlo Simulations, G. Lee Warren, Robert Hinde
Population Size Bias In DescendantWeighted Diffusion Quantum Monte Carlo Simulations, G. Lee Warren, Robert Hinde
Robert Hinde
We consider the influence of population size on the accuracy of diffusion quantum Monte Carlo simulations that employ descendant weighting or forward walking techniques to compute expectation values of observables that do not commute with the Hamiltonian. We show that for a simple model system, the ddimensional isotropic harmonic oscillator, the population size must increase rapidly with d in order to ensure that the simulations produce accurate results. When the population size is too small, expectation values computed using descendantweighted diffusion quantum Monte Carlo simulations exhibit significant systematic biases.
Characterization Of Violet Emission From Rb Optical Pumping Cells Used In LaserPolarized Xenon Nmr Experiments, Indrajit Saha, Panayiotis Nikolaou, Nicholas Whiting, Boyd M. Goodson
Characterization Of Violet Emission From Rb Optical Pumping Cells Used In LaserPolarized Xenon Nmr Experiments, Indrajit Saha, Panayiotis Nikolaou, Nicholas Whiting, Boyd M. Goodson
Nicholas Whiting