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2P3/2:2P1/2 Partial Photoionization Cross-Section Ratios In The Rare Gases , James A.R. Samson, J.L. Gardner, Anthony F. Starace

Anthony F. Starace Publications

The ²P_3/2:²P_1/2 partial photoionization cross-section ratios have been measured for the rare gases in the ionization continuum and within resonance structure. The wavelength range for this study was from the ²P_1/2 ionization threshold to 304 Å. The ratio of the cross sections was found to be constant over this wavelength range, yielding ratios of 1.54, 1.77, 1.93, and 2.18 for Xe, Kr, Ar, and Ne, respectively. Within resonances, the ratio changed dramatically. Results are illustrated for xenon.

Intrinsic Viscosity Of Stiff Dumbbells From Time Correlation Functions, Gerald Wilemski

Physics Faculty Research & Creative Works

The intrinsic viscosity of a suspension of stiff dumbbells is evaluated by a time correlation function method. The required moments of the internal coordinates are calculated directly from the diffusion equation, without explicit evaluation of the Green's function. For the rigid dumbbell, the correct high frequency limit is obtained, disposing of recent doubts over this possibility. The interplay of dumbbell stiffness and shearing frequency is also illustrated.

Design Of Film—Substrate Single-Reflection Retarders, A.-R. M. Zaghloul, R. M.A. Azzam, N. M. Bashara

Electrical Engineering Faculty Publications

The design steps for film—substrate single-reflection retarders are briefly stated and applied to the SiO₂—Si film—substrate system at wavelength 6328 Å. The criterion of minimum-maximum error of the ellipsometric angle ψ is used to choose angle-of-incidence-tunable designs. Use is made of the (Φ-d) plane (angle of incidence versus thickness) to determine whether a given film—substrate system with known optical properties and film thickness can operate as a reflection retarder and to determine the associated angles of incidence and retardation angles. This leads to the concept of permissible-thickness bands and forbidden gaps for operation of a film—substrate …

Relationship Between The Linear Ringing Frequencies In 3he-A And 3he-B Near The Polycritical Point, Richard A. Webb, R. E. Sager, J. C. Wheatley

Faculty Publications

New measurements of parallel ringing in a quasi-ideal geometry for ³He-B near the temperature and pressure of the polycritical point suggest f_B²/f_A²∼5/2, where f_B and f_A are the linear parallel-ringing frequencies at a given temperature near T_c. This result approaches the prediction of theory using the Anderson-Brinkman-Morel and Balian-Werthamer states to describe ³He-A and ³He-B, respectively, and hence the results of Osheroff at melting pressure, but disagrees with earlier observations at pressures near the polycritical point.

Technique For Rapid Faraday Susceptibility Measurements, F.R. Szofran, W.L. Burmester, David J. Sellmyer, L.G. Rubin

David Sellmyer Publications

An apparatus is described which permits the rapid acquisition and computer analysis of temperature-dependent Faraday susceptibility data. The apparatus utilizes a relatively inexpensive, three-channel, data-acquisition system. Review of Scientific Instruments is copyrighted by The American Institute of Physics.

Gauge Invariance And Radiative Transition Probabilities, Ian P. Grant, Anthony F. Starace

Anthony F. Starace Publications

The relationship between recommendations of some recent papers on the choice of formula (length, velocity, or acceleration type) for calculating radiative transition probabilities is clarified.

Synthetic Analogs Of Active Sites Of Iron-Sulfur Proteins: Bis (O-Xylyldithiolato) Ferrate (Iii) Monoanion, A Structurally Unconstrained Model For The Rubredoxin Fe-S4 Unit, R. W. Lane, James A. Ibers, Richard B. Frankel, R. H. Holm

Physics

To complete the set of synthetic analogs of the three recognized types of active sites in iron-sulfur redox proteins, the compound (Et₄N)[Fe((SCH₂)₂C₆H₄)₂], derived from o-xylyl-α,α'-dithiol, has been prepared and its structure has been determined by x-ray diffraction. The bischelate anion contains a near-tetrahedral Fe(III)-S₄ coordination unit with small rhombic distortions and all Fe-S bond distances in the range 2.252-2.279 Å. Its electronic properties have been partially characterized by measurement of electronic absorption, paramagnetic resonance, Mössbauer spectra, and magnetic susceptibility. The analog, as …

17th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Final program and abstracts from the 17th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 4-8, 1975.

Effect Of Elliptically Polarized Light On The Angular Distribution Of Photoelectrons, James A. R. Samson, Anthony F. Starace

Anthony F. Starace Publications

The angular distribution of photoelectrons predicted for elliptically polarized light is shown to be the same as that predicted for partially polarized light having incoherent perpendicular electric field components equal to the electric field components along the major and minor axes of the ellipse.

Includes Corrigendum from J. Phys. B: Atom. Molec. Phys. 12:23 (1979), p. 3993.

Teaching-The Purpose Of Repeatable Testing: Response To Comment Of J. D. Edmonds, D.E. Golden, Robert Fuller, D.D. Jensen

Robert G. Fuller Publications

It is not clear that the comment "Grading and Regrading"' has very much to do with our article.' The comment seems rather to be a nostalgic statement recalling the good old days when with glee we cracked the whip and the students either shaped up or shipped out.

Our purpose in doing repeatable testing was not to become a "do your own thing" force, to raise everyone's grades, to "achieve well defined educational objectives" like teaching the solution to the inclined plane problem, to do away with certification, and most definitely our purpose was not to replace teachers with computer-programmed …

Sensitivity Of A Gas Filter Correlation Instrument To Variations In Atmospheric Profile And Earth Surface Temperatures, Joseph C. Casas

Physics Theses & Dissertations

The Gas Filter Correlation Radiometer Analyzer (GFCR), in application to the remote sensing of trace gases in the atmosphere, is potentially limited by the sensitivity of the measured upwelling thermal radiation to surface temperature and atmospheric temperature conditions. This study has been carried out to examine the principles of operation of the GFCR Analyzer and to obtain quantitative estimates of the errors produced in GFCR Analyzer measurements of CO (4.6μ), S02 (8.6μ), NH3 (11.0μ), and CH4 (8.1μ) resulting from uncertainties in the atmospheric temperature profile and ground temperature.

A simple mathematical prototype GFCR Analyzer was assumed. A line-by-line atmospheric radiative …

The Determination Of Double Mode Variable Star Periods, Arne A. Henden

Physics & Astronomy ETDs

ABSTRACT

The problem of determining the periods of objects oscillating in one or more modes is discussed. Although the methods described are applicable to many different kinds of objects and observations, the discussion has been limited to double mode Cepheid stars.

Two methods of solution are followed in detail. An autocorrela­tion technique based on the scatter of points in an amplitude-phase plane is used for most cases. A means of calculating smoothed mean curves is discussed. A Fourier transform method is presented for closely spaced data points, with prewhitening included for accurate secondary period and amplitude determinations.

Three test problems …

Theoretical Evaluation Of Selective Radiation–Absorbing Surface, K.R. O’Shea

Tanzania Journal of Science

An algol computer program is described, by means of which the spectral reflectivity for any angle of incidence may be calculated for a surface consisting of up to two thin absorbing films on a bulk substrate. The values of optical constant, n and k, for the materials used and also the thickness of the films, are the only data required. Calculated reflectivities have been shown to be consistent with experimental results.

On The Field-Induced Infra-Red Absorption Of Gaas, Frederick Ngawo Onyango

Tanzania Journal of Science

A theoretical survey of electric field–induced effects on one-and two-phonon absorption of GaAs is presented. The eigen-values and hence eigen-vectors are calculated for an external field applied along [001] and dependence of electro–absorption on the direction of radiation polarization established.

Theoretical Study Of Impurity-Induced First-Order Raman Spectra For The Alkali Halides, Arnold Karo, John Hardy

John R. Hardy Papers

A deformation-dipole model with first- and second-neighbor central short-range forces is used as a basis for calculating all symmetry-adapted combinations of eigenvectors (SACEV) necessary for the study of defect vibrations in alkali-halide crystals. As an example of the full set of spectral weight functions, which are tabulated separately, sample results are given for the predicted defect-activated E, Raman spectra for KCl, KI, RbCl, and KBr, assuming no force-constant changes and that the defect is located at a positive-ion site. The results show qualitative agreement with the earlier findings of Harley, Page, and Walker, even though the deformation-dipole model is not …

Theoretical Study Of Impurity-Induced First-Order Raman Spectra For The Alkali Halides, Arnold Karo, John R. Hardy

John R. Hardy Papers

A deformation-dipole model with first- and second-neighbor central short-range forces is used as a basis for calculating all symmetry-adapted combinations of eigenvectors (SACEV) necessary for the study of defect vibrations in alkali-halide crystals. As an example of the full set of spectral weight functions, which are tabulated separately, sample results are given for the predicted defect-activated E, Raman spectra for KC1, KI, RbCl, and KBr, assuming no force-constant changes and that the defect is located at a positive-ion site. The results show qualitative agreement with the earlier findings of Harley, Page, and Walker, even though the deformation-dipole model is not …

Some Comments On Correlation-Function Formulas For Polymer Intrinsic Viscosity, Walter H. Stockmayer, Gerald Wilemski, Hiromi Yamakawa, Genzo Tanaka

Physics Faculty Research & Creative Works

No abstract provided.

Energy And Angular Distribution Of Electrons Ejected From Helium By Fast Protons And Electrons: Theory And Experiment, Steven Trent Manson, Larry H. Toburen, Don H. Madison, Nikolaus Stolterfoht

Physics Faculty Research & Creative Works

A comprehensive study of the angular and energy distributions of electrons ejected in collisions of fast electrons and protons with He is presented. New experimental results for 300-keV, 1-MeV, and 5-MeV proton impact are reported along with theoretical results for 2-keV electron impact and 100-keV, 300-keV, 1-MeV, and 5-MeV proton impact. The theoretical results, based upon Born approximation with Hartree-Slater initial discrete and final continuum wave functions, show excellent agreement with experimental electron-impact results. Serious discrepancies are found between theory and experiment in the angular distribution of ejected electrons for forward angles for 100- and 300-keV proton impact; the discrepancies …

The Dynamics Of An Hcp Crystal With A Substitutional Defect, Pramod C. Karulkar

Dissertations and Theses

We examine the problem of the dynamics of a hexagonal close packed crystal with a single substitutional impurity. The effects of the mass and the force constant changes due to the introduction of the impurity atom are taken into account assuming nearest neighbor interactions under the harmonic approximation. Using Green’s function and group theoretical methods, the equations of motion for the perturbed normal modes are obtained in an exact form. The calculations are performed by allowing for very general force constant changes which can have noncentral as well as central contributions. Further, by assuming central forces, we simplify the equations …

Path Integrals With Arbitrary Generators And The Eigenfunction Problem, William B. Campbell, Paul Finkler, C. E. Jones, M. N. Misheloff

Paul Finkler Papers

We generalize the path integral formalism of quantum mechanics to include the use of arbitrary infinitesimal generators, thus providing explicit expressions for solutions of a wide class of differential equations. In particular, we develop a method of calculating the eigenfunctions of a large class of operators.

Theory Of Impurity-Induced Infrared Absorption In Cubic Crystals, S. S. Jaswal, J. M. Wadehra

Physics and Astronomy Faculty Research Publications

A method to calculate the infrared absorption due to a very low concentration of defects in a diatomic cubic crystal is developed directly from the basic absorption equation in quantum mechanics when the impurity produces changes in mass and short-range force constants. It is shown that the absorption is due to the modes of T_1u symmetry about the defect and is proportional to the square of the projection of the amplitudes of the ions in the defect space onto the transverse-optic modes at the zone center as determined by the perturbation. A procedure to calculate the amplitudes of …

A Satellite Study Of The High Energy Proton Environment Under The Radiation Belt, Kailash Chandra Dhingra

Physics & Astronomy ETDs

Proton data outside of the South Atlantic Radiation anomaly (in the regions where h_min < 0) from the University of New Mexico High Energy Neutron and Proton Detector aboard OSO-6 satellite were analyzed in the present work. The detector was useful in the energy range from 75-145 Mev and the data were obtained during the period from August 1969 to January 1971. The altitude of the satellite varied from about 480 Km to 580 Km. Since the observed proton flux resulted from different source mechanisms a procedure was developed that allowed us to compute and separate the contributions made by different mechanisms in the observed protons. New evidence was derived from the study of the Down-Up asymmetry both along the field direction and the zenith of the look direction (ZAP angle) which substantiated the hypothesis that either one or both of the processes of the radial and the pitch angle diffusion play active roles in the origin and the distributions of the protons in the inner radiation belt. It was argued that processes drive the trapped protons in the radiation belt into the regions where stable trapping is not possible and thus contribute to the observed protons in these regions. We were further able to compute the total diffusing flux; however, it was assumed that both the Splash and the Re-entrant albedo proton fluxes were equal. Since this assumption was not very accurate, an incorrect estimation of the diffusing proton flux might have resulted. In addition to the above, the flux and the energy spectrum of the albedo protons were derived at three different regions. These were then compared with the results of other investigators. Discrepencies in both the flux and the energy spectrum were observed. Our flux value of 1.05 protons/m² -sec-ster-Mev for the Re-entrant albedo at an energy of 85 Mev in the region where L = 2.5 was about a factor of two and a half higher than estimated by Ray (1967). No west-east asymmetry was observed in the true proton flux (proton flux obtained by subtracting the background contamination from the observed proton flux), within the limits of the experimental error. Since such an asymmetry was expected if we assume that the albedo protons alone constitute the true protons, it was concluded …

Double Rainbow And Dark Band In Searchlight Beam, J. Harsch, Jearl D. Walker

Physics Faculty Publications

No abstract provided.

Rbe-Dose Relations For Neutrons And Pions, Robert Katz, S. C. Sharma

Robert Katz Publications

RBE-Dose relations have been calculated from cellular radiosensitivity parameters and theoretical particle-energy spectra in tissue, of the secondary particles from neutron and negative pion irradiations. The theoretical results are compared with clinical and radiobiological data for normal tissue, tumors, and cells in culture. Formulae for calculation, cellular parameters, and the needed properties of equivalent “track-segment bombardments” are given, for several mammalian cells irradiated with pions and with neutrons of several energies.

Résumé
Rapports EBR-dose pour neutrons et pions
A partir des paramètres de la radiosensitivité cellulaire et du spectre théorique, dens le tissu, de l’énergie d’atomes secondaires provenant d’irradiations de …

Temperature Dependence Of Magnetoresistance In Ni3al System, Paul D. Hambourger, R. J. Olwert, C. W. Chu

Physics Faculty Publications

The transverse magnetoresistance of stoichiometric and off-stoichiometric polycrystalline samples of the Ni3Al system has been measured over the temperature range 1.2C. The data are in qualitative agreement with the theoretical predictions of Chang et al. based on a model of the magnetoresistance of an itinerant ferromagnet, but the observed magnetoresistance is considerably larger than predicted.

Quadrupole Couplings Of N12 And B12 Implanted In Metal Single-Crystals, Richard C. Haskell, Francis David Corell, Leon Madansky

All HMC Faculty Publications and Research

Measurements have been made of the quadrupole couplings of 12N implanted in single crystals of Be and Mg and of 12B implanted in a single crystal of Zn. A comparison of the 12N couplings in Be and Mg suggests that (i) the final stopping sites of the implanted 12N ions are substitutional sites, i.e., the 12N ions occupy metal-ion lattice positions, and (ii) the 12N ions implanted in Be and Mg have the same charge state and quadrupole shielding factor. A procedure is outlined for deducing Q(12N). The 12B couplings in Zn imply the existence of two inequivalent stopping sites. …

Binary Nucleation. I. Theory Applied To Water-Ethanol Vapors, Gerald Wilemski

Physics Faculty Research & Creative Works

A quantitative study of nucleation in vapor mixtures of ethanol and water near 273°C is presented. First, Reiss' theory of binary nucleation is reexamined. The theory is modified slightly in order to yield the proper limit for homogeneous nucleation in a one-component system. Moreover, a corrected expression for the equilibrium concentration of mixed clusters is derived. Calculations of the critical vapor activities needed to produce a visible condensate are presented and compared with the results of Flood's cloud chamber experiments. The agreement is only fair, but qualitative accord is found.

Damage Analysis Modified Trac Computer Program (Damtrac), George H. Baker Iii, Alan D. Mcnutt, G. Bradford Shea, David M. Rubenstein

School of Integrated Sciences - Faculty Scholarship

A computer program tailored for EMP damage analysis of solid-state circuitry has been developed by modifying the existing TRAC network analysis program. Modification of the TRAC diode and transistor models to include breakdown parameters and the addition of a semiconductor device parameter library have greatly simplified the analyst's task. An added feature is a subroutine that automatically calculates the amplitude and duration of transient power dissipated in electronic circuit components.

Binary Nucleation. Ii. Time Lags, Gerald Wilemski

Physics Faculty Research & Creative Works

The role of the time lag needed to attain steady state nucleation in binary vapors is discussed. Under appropriate conditions it is possible to obtain both a large predicted rate of binary nucleation and a large time lag. In this circumstance, homogeneous nucleation of the more concentrated component may be the predominant process. It is of obvious importance to the experimentalist to differentiate between these possibilities. Approximate formulas for the time lags are developed, and representative calculations for the ethanol-water system are reported.

Effects Of Anisotropic Electron-Ion Interactions In Atomic Photoelectron Angular Distributions, Dan Dill, Anthony F. Starace, Steven T. Manson

Anthony F. Starace Publications

The photoelectron asymmetry parameter β in LS coupling is obtained as an expansion into contributions from alternative angular-momentum transfers j_t. The physical significance of this expansion of β is shown to be that (i) the electric-dipole interaction transfers to the atom a characteristic single angular momentum j_t=l₀, where l₀ is the photoelectron's initial orbital momentum, whereas (ii) angular-momentum transfers j_t≠l₀ indicate the presence of anisotropic (i.e., term-dependent) interaction of the outgoing photoelectron with the residual ion. For open-shell atoms the photoelectron-ion interaction is generally anisotropic; photoelectron phase shifts …