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A Low Frequency Phase Shift Method, Ronnie Carroll Mcmillan

Masters Theses

"The phase shift method of measuring atomic lifetimes is particularly useful because it allows us to make measurements in the steady state mode instead of in the transient mode. High frequency phase shift techniques cause many problems. The equipment, which was designed and built to make low frequency phase shift techniques possible, is shown schematically and discussed. The new experimental techniques employed in our apparatus are a phase multiplier and a unique method of using a photomultiplier as a mixer. In the photomultiplier the final dynode is used as the grid of a triode. The next to the last dynode …

Consistency And Cluster Size In The Effective Field Theories Of Ferromagnetism, J. G. Chervenak, Harry A. Brown

Physics Faculty Research & Creative Works

No abstract provided.

Mixed Magnetic Systems: A Model With Application To (1-X)Cdcr2s4 · Xcdcr2se4, Harry A. Brown

Physics Faculty Research & Creative Works

The Curie temperatures and asymptotic Curie temperatures are calculated for mixed magnetic systems by a semi-classical Bethe-Peierls-Weiss cluster approach. The systems are typified by (1-x) CdCr2Se4 · xCdCr2Se4 in which the substitution changes the anions but not the magnetic cations. It is found that next-nearest-neighbor interactions are needed to match the data but that, with them, excellent agreement can be obtained for a reasonably unique choice of the exchange integrals. © 1969.

Semiempirical Determination Of The Hydrogen Bond Energy For Water Clusters In The Vapor Phase. I. General Theory And Application To The Dimer, Richard W. Bolandee, James L. Kassner, Joseph T. Zung

Physics Faculty Research & Creative Works

A simple semiempirical method is given for determining the hydrogen bond energy for water clusters in the vapor phase. This method is based on a general statistical-mechanical theory of clustering. The partition function for a system of clusters is used to determine the equilibrium distribution of clusters. In conjunction with available thermodynamic and spectroscopic data, the cluster equilibrium constants can be used to calculate the cluster potential energy and the hydrogen bond energy. Results for the water dimer agree quite well with other reported values obtained either by quantum-mechanical calculations or approximate thermodynamic estimates. A correct temperature dependence of the …

Geophysical Institute Annual Report 1968-69, University Of Alaska Fairbanks. Geophysical Institute

GI Reports

The 1968–69 Geophysical Institute Annual Report presents an overview of the year’s scientific research achievements across the Institute’s disciplines, alongside operational summaries covering finances, administrative changes, and other key activities.

Longitudinal Optical Phonon-Plasmon Coupling In Ionic Semiconductors, Thomas Joseph Mcmahon

Doctoral Dissertations

"The coupling of free carriers and lattice vibrational modes is studied in CdS and InSb by room temperature far infrared reflectance measurements. When the free carrier concentration is such that the plasma frequency is at or near the longitudinal optical mode frequency it is shown that while the transverse modes remain fixed, the longitudinal modes mix with the plasma mode and are shifted in a manner similar to that described by Varga in 1965. Using the dielectric function for the coupled system permits the determination of electron effective masses by reflectance measurements with lattice effects excluded. This method allows one …

Detection Of Vibrationally Excited N2 By Superelastic Electron Impact, Paul Burrow, Paul Davidovits

Paul Burrow Publications

We have observed electrons scattered superelastically from nitrogen molecules vibrationally excited by quenching collisions with optically excited rubidium atoms. Analysis of the energy gained by the electrons shows that in more than 10% of the quenching collisions the highest energetically allowed vibrational state of N₂, v=5, is populated. The relative superelastic cross section for collisions between molecules in this state and electrons is measured and compared with that predicted by detailed balance.

Ionic Transport In Potassium Chloride, Robert Fuller, Charles L. Marquardt, Michael H. Reilly, John C. Wells Jr.

Robert G. Fuller Publications

The electrical conductivity and chlorine ion diffusion in KC1 and KCl:SrC1₂ single crystals have been analyzed by least-squares methods, using as a model a perfect crystal perturbed by five defects: isolated anion vacancies, isolated cation vacancies, divalent cation impurities, divalent cation-impurity-cation-vacancy complexes, and vacancy pairs. The transport equations were derived from this five-defect model using a simple theory for noninteracting particles, except for the nearest-neighbor binding to form complexes and vacancy pairs, and using the same theory including long-range Coulomb interactions between the isolated defects. This latter theory yielded the better description of the experimental results. However, the analyses …

Measurement Of Electron Spin-Lattice Relaxation Times Using Ordinary Epr Spectrometers, David C. Look, Donald R. Locker

Physics Faculty Publications

No abstract provided.

Rotational Excitation Of Polar Molecules By Electrons, Marvin H. Mittleman, Jerry Peacher, Balazs F. Rozsnyai

Physics Faculty Research & Creative Works

Rotational excitation of polar molecules is calculated in the approximation that the electron transit time is short compared with rotational periods with the result of an E^-1 behavior of the cross section. Diffusion cross sections are calculated for Δl=0,1,2. Significant corrections to the Born approximation are obtained for large dipole moments. The range (in energy) of applicability of the result is discussed in terms of the energy dependence of the corrections, and a novel energy dependence of these corrections is encountered and explained.

Energy Deposition By Electron Beams And Δ Rays, E. J. Kobetich, Robert Katz

Robert Katz Publications

The product of two empirical relations, for the practical range and the transmission probability of normally incident electrons through plane sheets of matter, may be differentiated to yield a simple formulation of the energy deposition by electron beams, in agreement with more complex formulations and with experimental data. When combined with the δ-ray distribution formula, these results provide a theory of the spatial distribution of ionization energy about the path of a rapidly moving ion, which is basic to theories of radiation damage and detection.

The Construction Of A Portable Hologram Camera, Michael Bruce Elzinga

Masters Theses

No abstract provided.

Precision Measurement Of The Electronic G Factors Of The Alkali Metals, Paul A. Vanden Bout, Erol Aygun, Vernon J. Ehlers, Tuncay Incesu

University Faculty Publications and Creative Works

We have measured the ratios of the electronic g factors of Na23, Rb85,87, and Cs133 to that of K39, using the atomic-beam magnetic-resonance technique. The results are gJ(Na23)gJ(K39)=1.0000007 (2), gJ(Rb85,87)gJ(K39)=1.0000182 (2), and gJ(Cs1333)gJ(K39)=1.0001231 (3). These results, combined with the results of other researchers, yield the following absolute g factors for the alkali metals: gJ(Na)=-2.002297 (2), gJ(K)=-2.002295 (2), gJ(Rb)=-2.002332 (2), and gJ(Cs)=-2.002542 (2). These g factors, with the exception of the value for Cs, are in good agreement with theoretical values.

Nuclear Spin, Hyperfine-Structure Separation, And Nuclear Magnetic Moment Of 18-Min Rb88, Paul A. Vanden Bout, Antoni Dymanus, Vernon J. Ehlers, Michael H. Prior

University Faculty Publications and Creative Works

We have used the atomic-beam magnetic-resonance technique to measure the nuclear spin and the hyperfine-structure separation of 18-min Rb88 in the S122 electronic ground state. These results, combined with the Fermi-Segrè formula, yield the nuclear magnetic moment. Our results are: I=2, Δν=±1186.084(18) MHz, μI(uncorr)=±0.506(5) nm, μI(corr)=±0.508(5) nm. Present nuclear theory favors assignment of the negative sign to the value of the moment.

Measurement Of Positron Annihilation Line Shapes With A Ge(Li) Detector, H. (Henry) P. Hotz, J. M. Mathiesen, J. P. Hurley

Physics Faculty Research & Creative Works

We observed that the annihilation radiation photopeak in a Ge(Li) detector is considerably broader than that of a γ ray of the same energy. It seems reasonable to assume that the increased width is the result of the Doppler broadening of the annihilation photopeak, i.e., the longitudinal Doppler shift of the radiations is measured, while the transverse shift is measured in the usual angular-correlation experiments. By using a computer stripping program to remove the distortion produced by the finite energy resolution of our detector, we obtain momentum distributions in agreement with those which have been published. Only one detector is …

Longitudinal Optical Phonon-Plasmon Coupling In Cds, Robert John Bell, Thomas J. Mcmahon, Donald G. Rathbun

Physics Faculty Research & Creative Works

The longitudinal optical phonon-plasmon interaction theory of Varga is shown to be applicable to Gadoped CdS through the region of the first reflectivity minumum (2.5 to about 30 μ). The theoretical reflectivity vs wavelength for several concentrations of Ga-doped CdS are compared with experiment. The agreement between theory and experiment is particularly good for high dopant concentrations. A plot of the wavelength at minimum reflectivity vs impurity concentrations shows that the Varga theory does well in explaining the data. When phonon damping is introduced into the Varga dielectric function, the reflectivity over the whole region of resonance is more realistic. …

Application Of The Method Of Lattice Statics To Interstitial Cu Atoms In Cu, John Flocken, John Hardy

John R. Hardy Papers

We have calculated the lattice distortion produced by a body-centered interstitial Cu atom in a Cu host lattice. The calculations have been carried out consistently on the basis of discrete lattice theory, using the technique of lattice statics which is based on the Fourier transformation of the direct-space equilibrium equations. The force constants for the perfect lattice have been taken from measured phonon-dispersion curves, and we have used Huntington's Born-Mayer potential to describe the interaction between the interstitial atom and the atoms of the host lattice. The comparison of our results with those obtained by earlier workers, using semidiscrete matching …

A Generalized Analytical Theory Of The Response Of The Photoconductor, M Sameh Said

Archived Theses and Dissertations

No abstract provided.

Theoretical Analysis Of The Vibrations And Rotations Of The B¹[Sigma][Mu] State Of The Hydrogen Molecule, Sandra Zink Moody

Physics & Astronomy ETDs

Theoretical calculations of the rotational-vibrational constants of the B¹Σ⁺_u state of H₂ were made using the Dunham analysis and by fitting equations to energy eigenvalues. The potential energy function for the nuclei used in the calculations was computed by W. Kolos and L. Wolniewicz using the variational technique. The power series used in the Dunham analysis made use of Stirling's central difference interpolation polynomial. The equilibrium separation R_e found from the Born-Oppenheimer potential is 2. 42916₅ atomic units, differing from the Kolos-Wolniewicz value of 2.4288. Adiabatic corrections were taken into account through a …

New Solutions Of The Einstein-Maxwell Equations From Old, B. Kent Harrison

Faculty Publications

Methods are discussed with which one may derive theorems which allow one to generate new solutions of the Einstein-Maxwell equations from old ones. The old solutions used to generate new ones must admit at least one nonnull Killing vector and may be required to satisfy other conditions, depending on the theorem derived. Examples of derivable theorems are shown; these theorems are used in turn to show how generation of new solutions is accomplished. Examples of the latter are shown, such as generation of Brill or electrified NUT space from the Schwarzschild solution, generation of a new twisted Melvin universe from …

Modified Phase Representation And Effects Of Inelasticity In N/D Calculation Of P-Wave Pion-Pion Scattering, Barbara N. Hale, Arnold Tubis

Physics Faculty Research & Creative Works

An N/D formalism based on a modified phase representation is used to study the effects of inelasticity on the ρ-wave pion-pion amplitude. The effects of high-energy inelasticity are introduced in terms of the assumed behavior of the high-energy phase (not phase shift) of the partial-wave amplitude. Using a ρ-exchange input force with the experimental ρ mass and a ρ width of about 100 MeV, and the assumption that the average phase is (1/2)π, for total c.m. energies greater than about 8M_π, we find that there is no appreciable reduction in the width of the calculated ρ-wave resonance. We …

Response Prediction For The Oso-G Satellite Solar Neutron Instrument By Matrix Methods., John Coalmer Conklin

Physics & Astronomy ETDs

Properties of the University of New Mexico’s solar neutron instrument for use on the NASA 0S0-C satellite were investigated. A sensor model was developed by use of two computer codes. First, the total efficiency of the converters was calculated by a simulation code with a resulting total efficiency at 100 Mev of approximately two per cent of which four-fifths was carbon recoil contribution.

Second, geometry properties of the instrument were provided by a Monte Carlo program, with maximum geometry efficiency equaling about fourteen per cent. These were combined to give a total response profile for the instrument which was expressed …

Critical Assessment Of The Polarized-Orbital Method In Atomic Scattering, Marvin H. Mittleman, Jerry Peacher

Physics Faculty Research & Creative Works

The method of polarized orbitals used in calculating electron-atom scattering amplitudes has two obvious flaws: the wave function is discontinuous, and the method is not variationally based. These are corrected in a somewhat arbitrary manner, and it is found that the results then depend upon a parameter of the theory sufficiently strongly that there are serious doubts about the predictive nature of the theory.

Three-Quasiparticle Intruder State In Te125 And The Magnetic Moment Of Sb125, N. J. Stone, Richard B. Frankel, D. A. Shirley

Physics

The levels of Te¹²⁵ have been studied using Sb¹²⁵ nuclei, polarized at T=0.014°K in an iron lattice, and Ge(Li) detectors. The magnetic moment of Sb¹²⁵ was determined as (2.59±0.03) μ_N. Levels (spins) were assigned at 35.9(3/2+), 145.4(11/2-), 322.2(9/2-), 443.7(probably 3/2+), 462.5(5/2+), 525.4(probably 9/2-), 636.1(7/2+), 642.3(7/2+), 671.6(5/2+) (energies in keV). The even-parity levels could be identified with levels calculated by Kisslinger and Sorensen. Using their wave functions, we calculated E2/M1 mixing ratios and branching ratios, finding quite good agreement. The odd-parity states are of special interest. The 11/2-145.4-keV state and 9/2-525.4-keV state …

10th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 10th 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 19-20, 1968.

Perturbation‐Theoretic Approach To Potential‐Energy Curves Of Diatomic Molecules, Robert Parr, Ronald White

Center for Advanced Mineral and Metallurgical Processing (CAMP)

A perturbation theory is developed whereby the diatomic molecular potential energy W(R) as a function of the internuclear distance R is expressed, for R near R_e, as a power series in the parameter λ = 1 − (R_e/R), W(λ) = w₀ + ∑ (w_n − w_n-1)λ^n.

Truncations of this series have the form of finite power series in R⁻¹. The quantities w_n are obtained simply as perturbation energies for a purely kinetic‐energy perturbation at R_e, by setting up the problem in confocal elliptic coordinates, in …

Crossed Field Trochoidal Trajectory Devices For Investigating The Reflection Of Slow Electrons From Metallic Surfaces, Stan Lemaster

Masters Theses & Specialist Projects

The objective of this study was to build preliminary devices . which could be used to measure electron reflection coefficient values using crossed electric and magnetic fields. The technique for using crossed fields to measure reflection coefficients was developed at Air Force Cambridge Research Laboratories. The reflection coefficient is the ratio of the number of electrons in a reflected beam to the number of electrons in an incident beam striking a surface.

The work described herein was a part of a project authored by AFCRL under contract AF19 (628)-5940; Project 8605 (with Western Kentucky University being the contractor) which was …

A Study Of The 16.7 Mev Level Of The 5He, James David George

Masters Theses

No abstract provided.

Modified Dispersion Relations And Π Π Scattering, David J. George, Barbara N. Hale, Arnold Tubis

Physics Faculty Research & Creative Works

The ππ S-wave scattering-length predictions of Weinberg have been tested by using dispersion sum rules for the infinite-energy cross section. Reasonable agreement is obtained with the infinite-energy cross section (≈15 mb) estimated from the factorization theorem for the Pomeranchon Regge residues. Experimental phase-shift data of Gutay et al., Walker et al., and Baton et al. are used in estimating the dispersion integrals. The analysis seems to rule out an I = 0 S-wave scattering length ⪞0.4μ^-1.

Infrared Absorption Properties Of Lih, Lid Mixed Crystals, Sitaram S. Jaswal, John R. Hardy

John R. Hardy Papers

The normal modes of pure LiH and LiD, required in impurity mode calculations, have been computed on the basis of the deformation-dipole model. Neutron-scattering results of Verble, Warren, and Yarnell for Li⁷D, along with some other experimental quantities, have been used to determine the various parameters involved. It is found that the frequency spectrum of LiH has a gap and that a substitutional D^- ion produces a local mode in this gap whose frequency has been computed, together with its amplitude at the impurity. The infrared absorption frequency associated with this local mode and its integrated absorption …