Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Institution
-
- University of Nebraska - Lincoln (37)
- Missouri University of Science and Technology (29)
- Utah State University (15)
- Portland State University (9)
- Selected Works (8)
-
- Cleveland State University (7)
- Wright State University (7)
- University of Miami (6)
- University of New Orleans (5)
- William & Mary (5)
- California Polytechnic State University, San Luis Obispo (4)
- Old Dominion University (4)
- St. John Fisher University (4)
- Iowa State University (3)
- Bard College (2)
- City University of New York (CUNY) (2)
- Claremont Colleges (2)
- University of Nebraska at Omaha (2)
- University of Windsor (2)
- Virginia Commonwealth University (2)
- Western Michigan University (2)
- Bryn Mawr College (1)
- Dominican University of California (1)
- Florida Institute of Technology (1)
- Grand Valley State University (1)
- SelectedWorks (1)
- Smith College (1)
- Southern Adventist University (1)
- Swarthmore College (1)
- The University of San Francisco (1)
- Keyword
-
- Ground State (3)
- Trans-polyacetylene (3)
- Atomic orbitals (2)
- CHEMICAL COMPOSITION (2)
- Charge transfer (2)
-
- Coulomb functions (2)
- EXTINCTION (2)
- F region (2)
- Gallium arsenide (2)
- Graphite (2)
- III-V semiconductors (2)
- Optical Properties (2)
- Orthogonalization methods (2)
- Peierls Mechanism (2)
- Photoconductivity (2)
- Physics (2)
- Semiconductor switches (2)
- ULTRAVIOLET SPECTRA (2)
- 1080-Ion Cluster (1)
- ASTRONOMICAL SPECTROSCOPY, CARBON ISOTOPES, INTERSTELLAR MATTER, STELLAR ENVELOPES, ABSORPTION SPECTRA, CHARGE COUPLED DEVICES, INTERSTELLAR EXTINCTION (1)
- Acoustics (1)
- Aerosol Particle (1)
- Aluminium arsenides (1)
- Anti-Perovskite (1)
- Article (1)
- Atom transport (1)
- Auditory system (1)
- Auroral dynamics (1)
- Auroral observations (1)
- Band-Structure Method (1)
- Publication
-
- Physics Faculty Research & Creative Works (25)
- Physics Faculty Publications (19)
- All Physics Faculty Publications (13)
- Physics Faculty Publications and Presentations (7)
- Physics Articles and Papers (6)
-
- Robert Katz Publications (6)
- Peter Dowben Publications (5)
- Dissertations, Theses, and Masters Projects (4)
- John R. Hardy Papers (4)
- Physics (4)
- Physics Faculty/Staff Publications (4)
- Physics Publications (4)
- Sy-Hwang Liou Publications (4)
- Anthony F. Starace Publications (3)
- Barry R Holstein (3)
- Edward Schmidt Publications (3)
- M. Eugene Rudd Publications (3)
- All HMC Faculty Publications and Research (2)
- Anthony Roy Day (2)
- Beate Schmittmann (2)
- DSLS 1989-1990 (2)
- Department of Physics and Astronomy: Faculty Publications (2)
- Electrical & Computer Engineering Faculty Publications (2)
- Electrical Engineering Faculty Publications (2)
- Masters Theses (2)
- Materials Science and Engineering Faculty Research & Creative Works (2)
- Mechanical and Aerospace Engineering Faculty Research & Creative Works (2)
- Publications and Research (2)
- Timothy J. Gay Publications (2)
- Aerospace, Physics, and Space Science Faculty Publications (1)
- Publication Type
- File Type
Articles 151 - 170 of 170
Full-Text Articles in Physical Sciences and Mathematics
Thermospheric Dynamics During September 18-19, 1984, 2, Validation Of The Ncar Thermospheric General Circulation Model, G Crowley, B A. Emery, R G. Roble, H C. Carlson Jr., J E. Salah, Vincent B. Wickwar, K L. Miller, W L. Oliver, R G. Burnside, F A. Marcos
Thermospheric Dynamics During September 18-19, 1984, 2, Validation Of The Ncar Thermospheric General Circulation Model, G Crowley, B A. Emery, R G. Roble, H C. Carlson Jr., J E. Salah, Vincent B. Wickwar, K L. Miller, W L. Oliver, R G. Burnside, F A. Marcos
All Physics Faculty Publications
The validation of complex nonlinear numerical models such as the National Center for Atmospheric Research thermospheric general circulation model (NCAR TGCM) requires a detailed comparison of model predictions with data. The Equinox Transition Study (ETS) of September 17-24, 1984, provided a unique opportunity to address the verification of the NCAR TGCM, since unusually large quantities of high-quality thermospheric and ionospheric data were obtained during an intensive observation interval. In a companion paper (paper 1) by Crowley et al. (this issue) a simulation of the September 18-19 ETS interval was described. Using a novel approach to modeling, the TGCM inputs were …
Large-Angle Scattering In Positron-Helium And Positron-Krypton Collisions, D. R. Schultz, C. O. Reinhold, Ronald E. Olson
Large-Angle Scattering In Positron-Helium And Positron-Krypton Collisions, D. R. Schultz, C. O. Reinhold, Ronald E. Olson
Physics Faculty Research & Creative Works
We have calculated differential cross sections as a function of the projectile scattering angle for positron-helium and positron-krypton collisions using the classical-trajectory Monte Carlo technique. These intermediate- velocity collisions have been simulated by various independent-electron and n-electron models, using both screened Coulomb and quantum model potentials to approximate the effects of electron-electron interactions. These several models all indicate that scattering of positrons to large angles in ionizing collisions persists to high impact velocities. In a previous work [Phys. Rev. A 38, 1866 (1988)] we proposed that the recent experiments that have measured the total cross section for positronium formation could …
Oxidation-Reduction Behavior Of Undoped And Sr-Doped Lamno3 Nonstoichiometry And Defect Structure, J. H. Kuo, Harlan U. Anderson, Don M. Sparlin
Oxidation-Reduction Behavior Of Undoped And Sr-Doped Lamno3 Nonstoichiometry And Defect Structure, J. H. Kuo, Harlan U. Anderson, Don M. Sparlin
Materials Science and Engineering Faculty Research & Creative Works
Undoped and Sr-doped LaMnO3 showed reversible oxidation-reduction behavior. These perovskites can be excess, stoichiometric or deficient in oxygen content depending on the specific conditions. Under very reducing conditions decomposition into new phases occurs. Phase stabilities for these oxides were determined. The results showed that Sr doping caused the LaMnO3 to dissociate at higher oxygen activities than those necessary for undoped LaMnO3. Defect models are proposed to interpret the thermogravimetric results in which metal vacancies are assumed for the oxygen excess condition and oxygen vacancies are assumed for the oxygen deficient condition. Thermodynamic properties were calculated which …
Local Density Approximation Study Of Transition Andf-Electron Materials, Zhi Wei Lu
Local Density Approximation Study Of Transition Andf-Electron Materials, Zhi Wei Lu
Dissertations, Theses, and Masters Projects
The local density approximation (LDA) has been proved to be a powerful starting point for calculating electronic and structural properties for many real materials. We have studied the effects of particular forms of exchange-correlation potentials (the X{dollar}\alpha{dollar} and Hedin-Lundqvist form) upon the structural properties for the 3d Ti and 4d Zr using a highly accurate linearized augmented plane wave (LAPW) method. The calculated equilibrium volumes differ by 6-8% for these two forms (with X{dollar}\alpha{dollar} results in better agreement with experiment) with proportional differences in other structural properties, which we take to be an indication of the intrinsic reliability of the …
A Search For The Rare Decay Kaon(L) Going To Muon/Electron, John Fred Ginkel
A Search For The Rare Decay Kaon(L) Going To Muon/Electron, John Fred Ginkel
Dissertations, Theses, and Masters Projects
A sensitive search has been carried out for the rare decay $\rm K\sb{L}\to\mu e$. This decay violates conservation of separate lepton-number and thus is forbidden in the Standard Model of electro-weak interactions. Many new models have been proposed which could permit this process. The data were collected in the B5 beamline of the Alternating Gradient Synchrotron facility at the Brookhaven National Laboratory during the Spring, 1988 slow-extracted beam running period. The experiment was sensitive to approximately fifty million $\rm K\sb{L}\to\pi\pi$ decays. No $\rm K\sb{L}\to\mu e$ candidate events were detected. The 90% confidence level upper limit for the branching ratio is …
A Measurement Of The Decay Rate For The Process Kaon(L) Going To Positive Muon Negative Muon, Christopher John Kenney
A Measurement Of The Decay Rate For The Process Kaon(L) Going To Positive Muon Negative Muon, Christopher John Kenney
Dissertations, Theses, and Masters Projects
A sample of 87 events of the GIM suppressed decay K$\sb{\rm L} \to \mu\sp+\mu\sp-$ were observed in an experiment performed in 1988 at the Brookhaven National Laboratory. Concurrently, 8,887 examples of the CP-violating decay K$\sb{\rm L} \to \pi\sp+\pi\sp-$ were also seen. The apparatus consisted of a double-magnet spectrometer as well as electromagnetic and muon detector systems. From the previously measured branching ratio for K$\sb{\rm L} \to \pi\sp+\pi\sp-$ and the different instrumental acceptances of the detector for the two decays, the data sample was normalized to the effective number of K$\sb{\rm L}$ decays observed. A value for the ratio (K$\sb{\rm L} …
Nmr On Single Crystals Of Potassium Cyanogen Bromide (A Measurement Of The Orientational Probability Distribution Function Of The Negatively Charged Cyanogen Ion), Jeffrey Howard Walton
Nmr On Single Crystals Of Potassium Cyanogen Bromide (A Measurement Of The Orientational Probability Distribution Function Of The Negatively Charged Cyanogen Ion), Jeffrey Howard Walton
Dissertations, Theses, and Masters Projects
Single crystals of K(CN)$\sb{\rm x}$/(Br)$\sb{\rm 1-x}$ enriched in $\sp{15}$N have been studied by $\sp{15}$N NMR. Because of the anisotropic chemical shift, the NMR frequency spectrum of the orientational glass state reflects the distribution of cyanide orientations. By studying the spectrum at many orientations of each crystal, the orientational probability distribution function P($\Omega$) has been determined for x = 0.50 and for x = 0.20. The probability function is largest along the (100) directions, intermediate in the (110) directions, and nearly 0 along the (111) directions. The NMR determined P($\Omega$) is presented graphically and in terms of the Kubic Harmonic functions. …
Analytically Reduced Form Of Multicenter Integrals From Gaussian Transforms, Jack C. Straton
Analytically Reduced Form Of Multicenter Integrals From Gaussian Transforms, Jack C. Straton
Physics Faculty Publications and Presentations
In a previous paper the analytically reduced form was found for the general class of integrals containing multicenter products of ls hydrogenic orbitals, Coulomb or Yukawa potentials, and plane waves. The method consisted of combining all angular dependence within a single quadratic form by means of a three-dimensional Fourier transform and a one-dimensional Feynman transform for each term in the product and an additional integral transformation to move the resulting denominator into an exponential to be summed with the vector products in the plane waves. This quadratic form was then diagonalized with respect to the (introduced) momentum integrals and diagonalized …
The Stability Of Hot Curved Space, Philip S. Gribosky, John F. Donoghue, Barry R. Holstein
The Stability Of Hot Curved Space, Philip S. Gribosky, John F. Donoghue, Barry R. Holstein
Physics Department Faculty Publication Series
The propagator is evaluated for the situation of a non-interacting scalar field at non-zero temperature in curved space-time. The coincidence limit is taken and the corresponding effective Lagrangian is constructed. Fluctuations are determined using a background metric which satisfies the Einstein equations. The resulting energy-momentum tensor is found to be that for an imperfect fluid. Metric fluctuations are found to be unstable (for most values of the cosmological constant) with an exponential growth characterized by a Jeans mass squared which is twice the classical value. Comparisons with previous calculations are also made.
Three-Body Interactions In Proton-Helium Angular Scattering, R. Dörner, J. Ullrich, H. Schmidt-Böcking, Ronald E. Olson
Three-Body Interactions In Proton-Helium Angular Scattering, R. Dörner, J. Ullrich, H. Schmidt-Böcking, Ronald E. Olson
Physics Faculty Research & Creative Works
H++He scattering at 0.5 MeV has been investigated using a coincidence technique that completely determines the three-body transverse momentum exchange in single ionization collisions. Three scattering regions could be distinctly recognized that are dominated by proton"helium-nucleus, proton-electron, or electron"helium-nucleus interactions. Calculations and the experimental data show that the coupling between the electronic and nuclear degrees of freedom is required to understand the dynamics for more than 97% of the ionizing collisions. © 1989 The American Physical Society.
Strong Continuum-Continuum Couplings In The Direct Ionization Of Ar And He Atoms By 6-Mev/U U38+ And Th38+ Projectiles, D. Schneider, D. Dewitt, A. S. Schlachter, Ronald E. Olson, W. G. Graham, J. R. Mowat, R. (Robert) D. Dubois, D. H. Loyd, V. Montemayor, G. Schiwietz
Strong Continuum-Continuum Couplings In The Direct Ionization Of Ar And He Atoms By 6-Mev/U U38+ And Th38+ Projectiles, D. Schneider, D. Dewitt, A. S. Schlachter, Ronald E. Olson, W. G. Graham, J. R. Mowat, R. (Robert) D. Dubois, D. H. Loyd, V. Montemayor, G. Schiwietz
Physics Faculty Research & Creative Works
Doubly differential cross sections have been measured as a function of the electron energy and observation angle for electron emission following collisions of 6-MeV/u U38+ and Th38+ on He and Ar. The electron-emission data show an enhancement at forward angles and a decrease at backward angles with respect to scaled-cross-section results based on the Born approximation. Comparison with classical-trajectory Monte Carlo calculations suggests that the deviation from the Born approximation can be explained by continuum-continuum couplings. By comparing with previously published data, we found that the forward enhancement as well as the backward decrease follow a q/vp (q,vp …
N, L Distributions For Electron-Capture From H(1s) By C⁶⁺And O8+, Ronald E. Olson, D. R. Schultz
N, L Distributions For Electron-Capture From H(1s) By C⁶⁺And O8+, Ronald E. Olson, D. R. Schultz
Physics Faculty Research & Creative Works
Total cross sections for electron-capture from the ground state of hydrogen by C6+(40, 50, 60, 80, 100 and 120 keV/u) and O8+(40, 50, 60, 80, 100, 120 and 140keV/u) have been calculated using the classical-trajectory Monte Carlo (CTMC) technique. We tabulate these cross sections as a function of projectile energy for (i) capture to all product states, (ii) capture to product n-levels, and (iii) capture to product n, l-levels. The results of these calculations agree with and extend previous CTMC n, ldistribution results. © 1989 IOP Publishing Ltd.
Electron Removal From Molecular Hydrogen By Fully Stripped Ions At Intermediate Energies, L. Meng, C. O. Reinhold, Ronald E. Olson
Electron Removal From Molecular Hydrogen By Fully Stripped Ions At Intermediate Energies, L. Meng, C. O. Reinhold, Ronald E. Olson
Physics Faculty Research & Creative Works
A classical phase-space model of the hydrogen molecule is presented and applied to the study of the electron-capture and -ionization processes in collisions of fully stripped ions with H2 at intermediate impact energies and charge states from 1 to 10. The model is based on the independent-electron and the impact-parameter approximations. The electron impinging-ion and electron target-nuclei interactions are exactly taken into account. The interaction between the electrons is approximated by model potentials. The calculated total cross sections for production of free electrons and capture of one electron are in good agreement with different experimental data. The ratio between the …
A Study Of Oxygen Precipitation In Heavily Doped Silicon, Robert Kurt Graupner
A Study Of Oxygen Precipitation In Heavily Doped Silicon, Robert Kurt Graupner
Dissertations and Theses
Gettering of impurities with oxygen precipitates is widely used during the fabrication of semiconductors to improve the performance and yield of the devices. Since the effectiveness of the gettering process is largely dependent on the initial interstitial oxygen concentration, accurate measurements of this parameter are of considerable importance. Measurements of interstitial oxygen following thermal cycles are required for development of semiconductor fabrication processes and for research into the mechanisms of oxygen precipitate nucleation and growth. Efforts by industrial associations have led to the development of standard procedures for the measurement of interstitial oxygen in wafers. However practical oxygen measurements often …
Mechanism Of Collisionally-Induced Transitions Among Fine-Structure Levels: Semiclassical Calculations Of Alignment Effects In The Na-He System, Laurie J. Kovalenko, Stephen R. Leone, John B. Delos
Mechanism Of Collisionally-Induced Transitions Among Fine-Structure Levels: Semiclassical Calculations Of Alignment Effects In The Na-He System, Laurie J. Kovalenko, Stephen R. Leone, John B. Delos
Arts & Sciences Articles
To gain insight into the mechanism of Na(3p)2P3/2→2P1/2 fine‐structure transitions induced by collision with He, we monitor the expectation values of the orbital‐ and spin‐angular momentum vectors, l and s, as a function of time along the trajectory, using a semiclassical formalism. In a typical collision, 〈s〉 remains nearly space‐fixed while 〈l〉 precesses about the rotating internuclear axis. Thus, in the interaction region, the projection of 〈l〉 onto the internuclear axis, 〈λ〉, remains nearly constant, and the molecular alignment of the orbital is preserved. We show how equations of motion for …
Pressure Dependence Of Ozone Interference In The Laser Fluorescence Measurement Of Oh In The Atmosphere [Comment], Thomas M. Hard, C. Y. Chan, A. A. Mehrabzadeh, Robert J. O'Brien
Pressure Dependence Of Ozone Interference In The Laser Fluorescence Measurement Of Oh In The Atmosphere [Comment], Thomas M. Hard, C. Y. Chan, A. A. Mehrabzadeh, Robert J. O'Brien
Chemistry Faculty Publications and Presentations
The authors comment on the paper by Shirinzadeh et al. (Applied Optics, vol. 26, p. 2102, 1987). They point out three errors which caused the overprediction of spurious HO data.
The Adiabatic Propagator, Br Holstein
The Adiabatic Propagator, Br Holstein
Barry R Holstein
The Feynman propagator is expanded in the adiabatic limit, wherein the time scale over which the potential varies is long compared to typical quantum mechanical oscillation times in the problem. Comparison with known exact results is made for two simple models.
Rigidity Percolation, Anthony Day, M. Thorpe, W. Xia
Rigidity Percolation, Anthony Day, M. Thorpe, W. Xia
Anthony Roy Day
No abstract provided.
The Adiabatic Theorem And Berry's Phase, Br Holstein
The Adiabatic Theorem And Berry's Phase, Br Holstein
Barry R Holstein
A study is presented of Berry's observation that when a quantum-mechanical system is transported on a closed adiabatic journey, a topological phase arises in addition to the usual dynamical phase expected from the adiabatic theorem. Consequences are explored in the case of a simple magnetic moment-magnetic field interaction and are shown to lead, among other things, to Dirac's famous relation between electric and magnetic charges.
Random Elastic Networks, Anthony Day, M. Thorpe, W. Xia
Random Elastic Networks, Anthony Day, M. Thorpe, W. Xia
Anthony Roy Day
Proceedings of the International Workshop on Condensed Matter Theories, 1988.