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Naturalness Lowers The Upper Bound On The Lightest Higgs Boson Mass In Supersymmetry, Greg W. Anderson, Diego Castano, Antonio Riotto Mar 1997

Naturalness Lowers The Upper Bound On The Lightest Higgs Boson Mass In Supersymmetry, Greg W. Anderson, Diego Castano, Antonio Riotto

Chemistry and Physics Faculty Articles

We quantify the extent to which naturalness is lost as experimental lower bounds on the Higgs boson mass increase, and we compute the natural upper bound on the lightest supersymmetric Higgs boson mass. We find that it would be unnatural for the mass of the lightest supersymmetric Higgs boson to saturate its maximal upper bound. In the absence of significant fine-tuning, the lightest Higgs boson mass should lie below 120 GeV, and in the most natural cases it should be lighter than 108 GeV. For modest tanβ, these bounds are significantly lower. Our results imply that a failure to observe …

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Scattering Of A Diagonally Incident Focused Gaussian Beam By An Infinitely Long Homogeneous Circular Cylinder, James A. Lock Mar 1997

Scattering Of A Diagonally Incident Focused Gaussian Beam By An Infinitely Long Homogeneous Circular Cylinder, James A. Lock

Physics Faculty Publications

I expand the radiation potential of an arbitrary monochromatic electromagnetic wave in the cylindrical coordinate eigenfunctions of the scalar Helmholtz equation. Since the resulting beam shape coefficients are found to be an inverse Fourier transform of the z component of the beam fields, the incident Gaussian beam is parameterized by a Fourier angular spectrum of plane waves. The beam's partial-wave coefficients are then obtained, as well as the scattered fields produced by the interaction of the beam with an infinitely long homogeneous circular cylinder. The fields are evaluated analytically in the far zone by the method of stationary phase, and …

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Morphology-Dependent Resonances Of An Infinitely Long Circular Cylinder Illuminated By A Diagonally Incident Plane Wave Or A Focused Gaussian Beam, James A. Lock Mar 1997

Morphology-Dependent Resonances Of An Infinitely Long Circular Cylinder Illuminated By A Diagonally Incident Plane Wave Or A Focused Gaussian Beam, James A. Lock

Physics Faculty Publications

The S matrix for scattering a diagonally incident focused Gaussian beam by an infinitely long circular cylinder is calculated, and the diagonal and off-diagonal elements of the matrix are physically interpreted. In addition, the TE and TM morphology-dependent resonances of the cylinder for plane-wave incidence are examined, and it is found that the cylinder size parameter at resonance increases as the angle of incidence of the plane wave increases. The size parameter increase is explained in terms of the heuristic model of morphology-dependent resonances. The presence of both TE and TM resonances in each of the epsilon-polarized and mu-polarized partial-wave …

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The Ubiquitous Coffee Filter, Norman F. Derby, Robert Fuller, Phil W. Gronseth Mar 1997

The Ubiquitous Coffee Filter, Norman F. Derby, Robert Fuller, Phil W. Gronseth

Robert G. Fuller Publications

What analyst would have predicted that Mr. CoffeeTM would diversify into the scientific supplies market? Nevertheless, that coffeemaker's filters, with their flat bottoms and fluted sides, have been popular in physics classroom experiments for some time now. Besides being cheap and readily available, coffee filters allow students to work experimentally with non-constant forces and, because the filters can be easily stacked without changing their aerodynamic profile, the variation in drag force with velocity can be studied. Since stacks of a few filters fall at speeds of about a meter per second and even a stack of ten reaches terminal …

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Physical Coupling Schemes And Qcd Exclusive Processes, David G. Robertson Feb 1997

Physical Coupling Schemes And Qcd Exclusive Processes, David G. Robertson

Physics Faculty Scholarship

I discuss application of the BLM method to obtain commensurate scale relations connecting QCD exclusive amplitudes to other observables, in particular the heavy quark potential.

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The Poisson Ratio Of Crystalline Surfaces, Marco Falcioni, Mark Bowick, Emmanuel Guitter, Gudmar Thorleifsson Feb 1997

The Poisson Ratio Of Crystalline Surfaces, Marco Falcioni, Mark Bowick, Emmanuel Guitter, Gudmar Thorleifsson

Physics - All Scholarship

A remarkable theoretical prediction for a crystalline (polymerized) surface is that its Poisson ratio (\sigma) is negative. Using a large scale Monte Carlo simulation of a simple model of such surfaces we show that this is indeed true. The precise numerical value we find is (\sigma \simeq -0.32) on a (128^2) lattice at bending rigidity (kappa = 1.1). This is in excellent agreement with the prediction (\sigma = -1/3) following from the self-consistent screening approximation of Le Doussal and Radzihovsky.

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Photoluminescence Properties Of Silicon Quantum-Well Layers, Peter N. Saeta, A. C. Gallagher Feb 1997

Photoluminescence Properties Of Silicon Quantum-Well Layers, Peter N. Saeta, A. C. Gallagher

All HMC Faculty Publications and Research

Nanometer-scale crystal silicon films surrounded by SiO2 were prepared by oxidizing silicon-on-insulator substrates prepared from SIMOX (separation by implantation of oxygen) and crystallized hydrogenated amorphous silicon films. Average silicon layer thickness was determined from reflection spectra. When sufficiently thin (<2 >nm), all layers emitted red photoluminescence under blue and UV cw excitation, with a spectrum that did not depend on the mean layer thickness. The spectrum was roughly Gaussian with a peak energy of 1.65 eV, which is lower than for most porous silicon spectra. The time scale for the luminescence decay was ~35 μs at room temperature and …

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Optical And Magneto-Optical Constants Of Mnpt3, K. W. Wierman, J. N. Hilfiker, R. F. Sabiryanov, Sitaram S. Jaswal, Roger D. Kirby, John A. Woollam Feb 1997

Optical And Magneto-Optical Constants Of Mnpt3, K. W. Wierman, J. N. Hilfiker, R. F. Sabiryanov, Sitaram S. Jaswal, Roger D. Kirby, John A. Woollam

Department of Physics and Astronomy: Faculty Publications

Optically thick films of MnPt3 were deposited on quartz using dc magnetron sputtering. The films were covered with an SiOx protective overcoat and annealed in vacuum at 850 °C for 1 h to form the crystalline L12 (Cu3Au) cubic structure. These films have a high degree of long-range order and are highly textured with the (111) axis along the film normal. Variable angle spectroscopic ellipsometry measurements were taken over the spectral range of 1.2–4.2 eV to determine the optical constants of both MnPt3 and the SiOx overcoat. Spectroscopic magneto-optic Kerr rotation and …

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Optical Properties Of Gan Grown On Zno By Reactive Molecular Beam Epitaxy, F. Hamdani, A. Botchkarev, W. Kim, H. Morkoç, M. Yeadon, J. M. Gibson, S.-C. Y. Tsen, David J. Smith, Donald C. Reynolds, David C. Look, K. R. Evans, Cole W. Litton, William C. Mitchel, P. Hemenger Jan 1997

Optical Properties Of Gan Grown On Zno By Reactive Molecular Beam Epitaxy, F. Hamdani, A. Botchkarev, W. Kim, H. Morkoç, M. Yeadon, J. M. Gibson, S.-C. Y. Tsen, David J. Smith, Donald C. Reynolds, David C. Look, K. R. Evans, Cole W. Litton, William C. Mitchel, P. Hemenger

Physics Faculty Publications

High quality wurtzite GaN epilayers have been grown on ZnO(0001) substrates by reactive molecular beam epitaxy. Photoluminescence and reflectivity measurements point to high quality presumably due to the near match of both the crystal lattice parameter and the stacking order between GaN and ZnO. In addition, the good films lack the characteristic yellow photoluminescence band. Any misorientation of the GaN epilayer planes with respect to the ZnO substrate is not detectable with polarized reflectivity. The x-ray double crystal diffraction measurements indicate this misorientation is much smaller than those for GaN epilayers on SiC and Al2O3 . © …

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On Protostellar Disks In Herbig Ae/Be Stars, Anatoly Miroshnichenko, Željko Ivezić, Moshe Elitzur Jan 1997

On Protostellar Disks In Herbig Ae/Be Stars, Anatoly Miroshnichenko, Željko Ivezić, Moshe Elitzur

Physics and Astronomy Faculty Publications

The spectral shape of IR emission from Herbig Ae/Be stars has been invoked as evidence for accretion disks around high-mass protostars. Instead, we present here models based on spherical envelopes with an r-1.5 dust density profile that successfully explain the observed spectral shapes. The spectral energy distributions of eight primary candidates for protostellar disks are fitted in detail for all wavelengths available, from visual to far-IR. The only envelope property adjusted in individual sources is the overall visual optical depth, and it ranges from 0.3 to 3. In each case, our models properly reproduce the data for IR excess, …

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Roughening And Preroughening Of Diamond-Cubic {111} Surfaces, Donald L. Woodraska, John A. Jaszczak Jan 1997

Roughening And Preroughening Of Diamond-Cubic {111} Surfaces, Donald L. Woodraska, John A. Jaszczak

Department of Physics Publications

A solid-on-solid model for {111} surfaces of diamond-cubic materials that correctly takes into account the diamond-cubic crystal structure has been developed for Monte Carlo simulation. In addition to a roughening transition at temperature TR, a distinct preroughening transition at TPR≈0.43TR is indicated by divergences in the surface specific heat and order-parameter susceptibility. Preroughening appears to arise naturally in our nearest-neighbor bond model from the entropic freedom available in the nontrivial crystal structure. Preroughening is shown to dramatically lower the nucleation barrier for growth and etching at low driving forces.

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[Fe Iv] In The Orion Nebula, R. H. Rubin, R. J. Dufour, Gary J. Ferland, P. G. Martin, C. R. O'Dell, J. A. Baldwin, J. J. Hester, D. K. Walter, Z. Wen Jan 1997

[Fe Iv] In The Orion Nebula, R. H. Rubin, R. J. Dufour, Gary J. Ferland, P. G. Martin, C. R. O'Dell, J. A. Baldwin, J. J. Hester, D. K. Walter, Z. Wen

Physics and Astronomy Faculty Publications

Using the Goddard High-Resolution Spectrograph on the Hubble Space Telescope, we measured the flux of [Fe IV] (3d5 4P5/2 --> 3d5 6S5/2) λvac = 2836.56 Å in the Orion Nebula, the first detection of an [Fe IV] line in an H II region. A useful upper limit is set on the sum of fluxes of [Fe IV] (3d5 4D5/2, 3/2 --> 3d5 6S5/2) λvac = 2568.4, 2568.2 Å. By comparing these observations with predicted fluxes from simply ``retrofitting'' our two previous photoionization models, …

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Raman-Scattering Study Of The Order-Disorder Phase Transition In Kscn, R. Li, John R. Hardy Jan 1997

Raman-Scattering Study Of The Order-Disorder Phase Transition In Kscn, R. Li, John R. Hardy

John R. Hardy Papers

Raman measurements were performed from room temperature to above the phase transition at 413 K on KSCN crystals. The internal mode spectra reveal a sideband above the internal CN stretching vibration which shows softening in frequency approaching the phase transition, while the CN mode shifts toward higher frequencies. Given that the sideband is a two-phonon process, involving an off-zone-center CN stretching mode and a lattice phonon, the substantial softening in its frequency shift indicates the possibility of an off-zone-center lattice instability related to the order-disorder phase transition. An anomalous temperature dependence was also found for the intensity of both the …

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Atomic And Electronic Structures Of Neutral And Charged Boron And Boron-Rich Clusters, J. Niu, B. K. Rao, P. Jena Jan 1997

Atomic And Electronic Structures Of Neutral And Charged Boron And Boron-Rich Clusters, J. Niu, B. K. Rao, P. Jena

Physics Publications

Ab initio molecular orbital theory based on both density functional formalism and quantum chemical methods has been used to calculate the equilibrium geometries, binding energies, ionization potentials, fragmentation patterns, and electronic structures of neutral and charged boron clusters containing up to six atoms. Calculations have also been performed on restricted geometries for BnX (n=1,5,12; X=Be, B, C) and B20 clusters to see if clusters can be designed so as to increase their stability. Energetics of doubly chargedB++n clusters have also been studied to find the critical size for Coulomb explosion. The results are compared with existing experimental and theoretical data.

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An Instantaneous Normal Mode Description Of Relaxation In Supercooled Liquids, T. Keyes, G. V. Vijayadamodar, Ulrich Zurcher Jan 1997

An Instantaneous Normal Mode Description Of Relaxation In Supercooled Liquids, T. Keyes, G. V. Vijayadamodar, Ulrich Zurcher

Physics Faculty Publications

Relaxation in supercooled liquids is formulated from the instantaneous normal modes (INM) point of view. The frequency and temperature dependence of the unstable, imaginary frequency lobe of the INM density of states, ⟨ρu(ω,T)⟩ (for simplicity we write ω instead of iω), is investigated and characterized over a broad temperature range, 10⩾T⩾0.42, in the unit density Lennard-Jones liquid. INM theories of diffusion invoke Im-ω modes descriptive of barrier crossing, but not all imaginary frequency modes fall into this category. There exists a cutoff frequency ωc such that modes with ω<ωc correspond to “shoulder potentials,” whereas the potential profiles include barrier-crossing double wells for ω>ωc. Given that only modes with ω>ωc contribute to diffusion, …

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Preferential Bonding Orientations Of Ferrocene On Surfaces, C. Waldfried, D. Welipitiya, C. W. Hutchings, H. S. V. De Silva, Gordon A. Gallup, Peter A. Dowben, W. W. Pai, Jiandi Zhang, J. F. Wendelken, N. M. Boag Jan 1997

Preferential Bonding Orientations Of Ferrocene On Surfaces, C. Waldfried, D. Welipitiya, C. W. Hutchings, H. S. V. De Silva, Gordon A. Gallup, Peter A. Dowben, W. W. Pai, Jiandi Zhang, J. F. Wendelken, N. M. Boag

Peter Dowben Publications

We have measured the molecular orientation and bonding of adsorbed ferrocene on Ag(100) and Cu(100) using angle-resolved photoemission spectroscopy (ARPES). The results for molecular adsorption on Ag(100) are complemented by high-resolution electron energy loss spectroscopy (HREELS) measurments and ab initio calculations for the ferrocene vibrational modes. The measurements indicate that ferrocene adsorbs on Ag(100) with the molecular axis perpendicular to the surface. In contrast, as indicated using ARPES and scanning tunneling microscopy, ferrocene adsorbed on the Cu(100) surface is oriented with the molecular axis parallel with the surface. Model calculations allow us to assign all of the observed vibrational modes …

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Maximum Individual & Vicinity-Average Dose For A Geologic Repository Containing Radioactive Waste, Thomas H. Pigford Jan 1997

Maximum Individual & Vicinity-Average Dose For A Geologic Repository Containing Radioactive Waste, Thomas H. Pigford

RISK: Health, Safety & Environment (1990-2002)

Explains the basis for his strong dissent to an NAS report on Yucca Mountain.

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Comparison Of The Projector Augmented-Wave, Pseudopotential, And Linearized Augmented-Plane-Wave Formalisms For Density-Functional Calculations Of Solids, N. A. W. Holzwarth, G. E. Matthews, Rodney Dunning, A. R. Tackett, Y. Zeng Jan 1997

Comparison Of The Projector Augmented-Wave, Pseudopotential, And Linearized Augmented-Plane-Wave Formalisms For Density-Functional Calculations Of Solids, N. A. W. Holzwarth, G. E. Matthews, Rodney Dunning, A. R. Tackett, Y. Zeng

Chemistry & Physics Faculty Publications

The projector augmented-wave (PAW) method was developed by Blöchl as a method to accurately and efficiently calculate the electronic structure of materials within the framework of density-functional theory. It contains the numerical advantages of pseudopotential calculations while retaining the physics of all-electron calculations, including the correct nodal behavior of the valence-electron wave functions and the ability to include upper core states in addition to valence states in the self-consistent iterations. It uses many of the same ideas developed by Vanderbilt in his "soft pseudopotential'' formalism and in earlier work by Blöchl in his "generalized separable potentials,'' and has been successfully …

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Plateau Tank Apparatus For The Study Of Liquid Bridges, Andrew Resnick, J. Iwan D. Alexander Jan 1997

Plateau Tank Apparatus For The Study Of Liquid Bridges, Andrew Resnick, J. Iwan D. Alexander

Physics Faculty Publications

An apparatus has been constructed and used to study the equilibrium and dynamical behavior of liquid bridges under reduced effective gravity. Liquid bridges are created and manipulated using six independent computer controlled stepper motors which drive linear motion tables. The bridges are visualized with a high magnification coherent Fourier optical system and in an orthogonal view using incoherent white light. By calibrating a density hydrometer and measuring the interfacial energy between the bridge and bath, reliable Bond numbers as low as 10−4 can be created and held stable for extended periods of time. Dimensional control of the liquid bridges approaches …

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An Embedded Ring Approach To The Vibrational Dynamics Of Amorphous Materials, John R. Dennison, T. E. Doyle Jan 1997

An Embedded Ring Approach To The Vibrational Dynamics Of Amorphous Materials, John R. Dennison, T. E. Doyle

All Physics Faculty Publications

A theoretical approach has been developed to model the vibrational modes of amorphous, two-dimensional materials. The method considers that the vibrational density of states is composed primarily of states originating from embedded ring structures of medium-range order. The materials are modeled as continuous random networks comprised of a statistical distribution of symmetric, planar rings with four to eight members. The rings are treated as local structural units embedded in the material, similar to molecules within a solid. The ring potentials are approximated with a valence force model (bond-stretching and bond-angle-bending force constants) modified by a third harmonic, effective force constant …

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The Global Ionosphere-Polar Wind System During Changing Magnetic Activity, Robert W. Schunk, Jan Josef Sojka Jan 1997

The Global Ionosphere-Polar Wind System During Changing Magnetic Activity, Robert W. Schunk, Jan Josef Sojka

All Physics Faculty Publications

A time-dependent, three-dimensional, multi-ion model of the global ionosphere-polar wind system was used to study the system's response to an idealized geomagnetic storm for different seasonal and solar cycle conditions. The model covered the altitude range from 90 to 9000 km for latitudes greater than 50° magnetic in the northern hemisphere. The geomagnetic storm contained a 1-hour growth phase, a 1-hour main phase, and a 4-hour decay phase. Four storm simulations were conducted, corresponding to winter and summer solstices at both solar maximum and minimum. The simulations indicated the following: (1) O+ upflows typically occur in the cusp and …

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Depth Measurement Of Doped Semiconductors Using The Hall Technique, G. C. Desalvo, David C. Look, Christopher A. Bozada, J. L. Ebel Jan 1997

Depth Measurement Of Doped Semiconductors Using The Hall Technique, G. C. Desalvo, David C. Look, Christopher A. Bozada, J. L. Ebel

Physics Faculty Publications

No abstract provided.

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The Interaction Of Fast Alpha Particles With Pellet Ablation Clouds, J. M. Mcchesney, P. B. Parks, R. K. Fisher, Ronald E. Olson Jan 1997

The Interaction Of Fast Alpha Particles With Pellet Ablation Clouds, J. M. Mcchesney, P. B. Parks, R. K. Fisher, Ronald E. Olson

Physics Faculty Research & Creative Works

The energy spectra of energetic confined alpha particles are being measured using the pellet charge exchange method [R. K. Fisher, J. S. Leffler, A. M. Howald, and P. B. Parks, Fusion Technol. 13, 536 (1988)]. The technique uses the dense ablation cloud surrounding an injected impurity pellet to neutralize a fraction of the incident alpha particles, allowing them to escape from the plasma where their energy spectrum can be measured using a neutral particle analyzer. The signal calculations given in the above-mentioned reference disregarded the effects of the alpha particles' helical Larmor orbits, which causes the alphas to make multiple …

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Momentum Spectra For Single And Double Electron Ionization Of He In Relativistic Collisions, C. J. Wood, Ronald E. Olson, W. Schmitt, R. Moshammer, J. Ullrich Jan 1997

Momentum Spectra For Single And Double Electron Ionization Of He In Relativistic Collisions, C. J. Wood, Ronald E. Olson, W. Schmitt, R. Moshammer, J. Ullrich

Physics Faculty Research & Creative Works

The complete momentum spectra for single and double ionization of He by [Formula Presented] [Formula Presented] [Formula Presented] have been investigated using a classical trajectory Monte Carlo method corrected for the relativistic projectile. The [Formula Presented] electron-electron interaction has been included in the post-collision region for double ionization to incorporate the effects of both the nuclear-electron and electron-electron ionizing interactions, and to access the effects of electron correlation in the electron spectra. Experimental measurements were able to determine the longitudinal momentum spectra for single ionization; these observations are in accordance with the theoretical predictions for the three-body momentum balance between …

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Complete Momentum Balance For Single Ionization Of Helium By Fast Ion Impact: Experiment, R. Moshammer, J. Ullrich, H. Kollmus, W. Schmitt, M. Unverzagt, H. Schmidt-Böcking, C. J. Wood, Ronald E. Olson Jan 1997

Complete Momentum Balance For Single Ionization Of Helium By Fast Ion Impact: Experiment, R. Moshammer, J. Ullrich, H. Kollmus, W. Schmitt, M. Unverzagt, H. Schmidt-Böcking, C. J. Wood, Ronald E. Olson

Physics Faculty Research & Creative Works

The collision dynamics of He single ionization by [Formula Presented] impact was explored using the reaction microscope of the Gesellschaft für Schwerionenforschung, a high-resolution integrated multielectron recoil-ion momentum spectrometer. The complete three-particle final-state momentum distribution (nine Cartesian components [Formula Presented]) was imaged with a resolution of [Formula Presented] by measuring the three momentum components of the emitted electron and the recoiling target ion in coincidence. The projectile energy loss has been determined on a level of [Formula Presented] and projectile scattering angles as small as [Formula Presented] became accessible. The experimental data which are compared with results of classical trajectory …

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Semiclassical Approach To The Hydrogen-Exchange Reaction Reactive And Transition-State Dynamics, Sophya V. Garashchuk, F. Grossmann, D. Tannor Jan 1997

Semiclassical Approach To The Hydrogen-Exchange Reaction Reactive And Transition-State Dynamics, Sophya V. Garashchuk, F. Grossmann, D. Tannor

Faculty Publications

Scattering matrix elements and symmetric transition-state resonances for the collinear H 2 + H → H + H 2 reaction are obtained using a time-dependent approach. The correlation function between reactant channel wavepackets and product channel wavepackets is used to determine the S-matrix elements. In a similar fashion, autocorrelation functions are used to extract the positions and widths of transition-state resonances. The time propagation of the wavepackets is performed by the improved semiclassical frozen Gaussian method of Herman and Kluk, which is an initial value, uniformly converged method. The agreement between the quantum and semiclassical results is far better …

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Analysis Of Scanning Tunneling Optical Spectroscopy Applied To Narrow Gap Semiconductors, James D. Patterson, James G. Mantovani Jan 1997

Analysis Of Scanning Tunneling Optical Spectroscopy Applied To Narrow Gap Semiconductors, James D. Patterson, James G. Mantovani

Aerospace, Physics, and Space Science Faculty Publications

Homogeneous II-VI narrow gap semiconducting alloys are of interest because of their use in infrared detectors. These compound semiconductor materials are inherently difficult to grow in bulk due to gravity induced convective flows. A microgravity growth environment has therefore been considered. In order to evaluate the quality of crystals grown in space compared to those grown on the ground, it is necessary to characterize both. One important aspect of this characterization is the study of stoichiometry, x. A characterization scheme using scanning tunneling optical spectroscopy (STOS) involves determining the spectral response of the photoexcited tunneling current for a semiconductor. By …

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Prediction Of Firing Pin Shape And 3d Matching Of Shells And Firing Pins Based On Firing Pin Impressions In Primers, Donald W. Dawson, Chris Hart, Bernard S. Gilbert Iii, Rafael A. Andrade, Joel H. Blatt Jan 1997

Prediction Of Firing Pin Shape And 3d Matching Of Shells And Firing Pins Based On Firing Pin Impressions In Primers, Donald W. Dawson, Chris Hart, Bernard S. Gilbert Iii, Rafael A. Andrade, Joel H. Blatt

Aerospace, Physics, and Space Science Faculty Publications

A variable resolution video machine vision system has been built which will determine the 3-D shape of a firing pin from the dent it has made in the primer of a shell. The system can also compare primer dents in different shells and determine if a 3-D match exists. A real time optical 3-D shape recognition feature allows the operator to align the shells, determine if there is a match, and quantify the quality of the 3-D match. The system uses a laser interferometer to project variable spatial frequency structural illumination on the shells which are viewed by video cameras. …

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Comment On “Electronic Structure Of Insulating Salts Of The-(Bedt-Ttf Family Studied By Low-Temperature Specific-Heat Measurements”, Nathanael Fortune, Yu V. Sushko Jan 1997

Comment On “Electronic Structure Of Insulating Salts Of The-(Bedt-Ttf Family Studied By Low-Temperature Specific-Heat Measurements”, Nathanael Fortune, Yu V. Sushko

Physics: Faculty Publications

Recently reported specific-heat measurements by Nakazawa and Kanoda between 20 and 50 K show no evidence for an expected antiferromagnetic ordering transition in the quasi-two-dimensional (2D) molecular conductor (Formula presented)-(BEDT-TTF)(Formula presented)Cu[N(CN)(Formula presented)]Cl [Y. Nakazawa and K. Kanoda, Phys. Rev. B 53, R8875 (1996)]. Although the absence of an observable transition was taken as evidence for 2D short-range ordering at elevated temperatures, even a small increase in pressure from the application of the grease used to mount the sample would shift this magnetic transition below 20 K. In their paper, Nakazawa and Kanoda erroneously assume that pressure-induced effects can be ruled …

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Academy Recommendations On The Proposed Yucca Mountain Waste Repository: Overview And Criticisms, Kristin S. Shrader-Frechette Jan 1997

Academy Recommendations On The Proposed Yucca Mountain Waste Repository: Overview And Criticisms, Kristin S. Shrader-Frechette

RISK: Health, Safety & Environment (1990-2002)

Offers alternative criticism of the NAS report.

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