Physical Sciences and Mathematics Commons^™

Analysis Of The Vibrational Modes Of The Triborate Anion, Panayiotis Th. D. Sphicas

Archived Theses and Dissertations

No abstract provided.

A Study Of The Sidereal Diurnal Variations Of Cosmic Rays Underground., Albert Brunsting

Physics & Astronomy ETDs

The sidereal diurnal variation of cosmic rays has been measured using underground (40 m.w.e.) meson telescopes located near Albuquerque, New Mexico (35.20°N, 106.41°w) and at Chacaltaya, Bolivia (16.31°s, 68.15°w). Each ofthe two locations has telescopes which scan the vertical and four inclined directions.

Two and three complete years were used for the tele­scopes at the Bolivia and New Mexico locations respectively. The average solar diurnal variations were calculated for each telescope for each month. Based on these monthly averages, the sidereal diurnal variations were computed. A correction was made in the analysis for any yearly modulation of the solar diunal …

Steady-State And Transient Currents In Organic Liquids By Injection From A Tunnel Cathode, Pavel Smejtek, David G. Onn, M. Silver

Physics Faculty Publications and Presentations

Experimental data are presented on the currents induced in organic liquids by injection from a tunnel cathode. The injection level was varied over a wide range resulting in almost no space‐charge limitation to almost complete space‐charge limitation. Results were different from that usually observed in solids, in that at low fields, the steady‐state current was proportional to V², while at high fields the current was proportional to V. By proper choice of electrode spacing and applied voltage, space‐charge‐limited current transients as low as 10⁻¹¹ A∕cm² and 5 sec transit times were observed. A smooth transition between the electrode‐limited and the …

Elastic Scattering Of 1.33 Mev Gamma Rays From Uranium, David Rood Schwandt

Masters Theses

No abstract provided.

Elastic Scattering Of 1.33 Mev Gamma Rays From Lead, William Jack Merrow

Masters Theses

No abstract provided.

Fabrication Of Lithium Drifted Germanium Detectors Of Planar Structures, Khin M. Yin

Masters Theses

No abstract provided.

Lattice Dynamics And Second-Order Raman Spectrum Of Naf, John R. Hardy, A. M. Karo, I. W. Morrison, C. T. Sennett, J. P. Russell

John R. Hardy Papers

The second-order Raman spectrum of NaF has been measured using an argon laser source. For a light beam incident along the [010] direction, polarized along the [001] direction, and viewed along the [100] direction, the scattered radiation is almost completely polarized. It is shown theoretically that it is possible to account for the polarization and the detailed shape of the observed spectrum within the experimental resolution using a Raman polarizability tensor whose second derivatives with respect to nuclear displacements depend only on the positions of first neighbors in the crystal, provided one uses the phonon frequencies derived from a deformation …

Multiple Charge States, Hyperfine Interactions, And Relaxation Processes Of Fe In 57Co-Doped Mgo, J. Chappert, Richard B. Frankel, A. Misetich, N. A. Blum

Physics

The Mössbauer spectra of cobalt-57-doped magnesium oxide have been studied between 1.3 and 550°K in external magnetic fields of up to 135 kOe for both single-crystal and polycrystalline samples. At room temperature and zero external magnetic field, the velocity spectrum is composed of three single lines, attributed to monovalent, divalent, and trivalent iron. In certain samples, for T2+ line undergoes a transition to a quadrupole doublet with a splitting ΔE_Q=0.30±0.02 mm/sec, while in certain other samples, annealed differently, no doublet is observed down to 1.5°K. The first case is in quantitative agreement with a random-strain model …

A Shock Tube Study Of Recombination In The Lean Hydrogen-Oxygen Reaction Based On The Infrared Emission From Water Vapor, Larry S. Blair

Physics & Astronomy ETDs

ABSTRACT

Recombination in the hydrogen-oxygen reaction has been studied by monitoring the growth of infrared emission at 2.7 microns from water vapor as it is formed behind incident shock waves. Experiments were carried out in gas mixtures with hydrogen-to-oxygen ratios between 1.0 and 0.33 and temperatures between 1435° and 1868°K. Reactants were diluted with 92-98% argon. The validity of the transparent gas approxi­mation (emission intensity proportional to (H20]) and the relationship between emission intensity and temperature were established by cali­bration experiments in which mixtures of water vapor and argon were shock-heated to temperatures between 1328° and 1982°K. Analysis of H20-emission …

Local Moment Formation And Resistivity Minima In Coal Alloys, G.R. Caskey, David J. Sellmyer

David Sellmyer Publications

Measurements of electrical resistivity, thermoelectric power, and magnetoresistance have been made from 1.4° to 300°K in alloys of 48%–57% cobalt in aluminum. At the equiatomic composition, CoAl has the CsCl structure. Resistance minima were observed in the vicinity of 30°K for cobalt concentrations between 50.4% and 51.5%. Below the resistance minima there is a temperature region where the dependence is approximately logarithmic before it saturates at about 1.4°K. The depth of the minima [ρ(1.4°K)– ρ( T_min)] and the thermopower at 4.2°K both show rather sharp peaks as a function of concentration in the vicinity of 50.5% cobalt. The …

Pulsed Nmr By Tone-Burst Generation, David C. Look, Donald R. Locker

Physics Faculty Publications

No abstract provided.

Meteorological Effects On Cosmic Rays At Albuquerque, New Mexico., David Nason Glidden

Physics & Astronomy ETDs

Ground-based observations of cosmic-ray intensity have the disadvantage of being more sensitive to variations of atmospheric temperature and pressure than to the more interesting variations in the primary cosmic radiation. It is, therefore, imperative to correct the recorded cosmic-ray intensity for variations of atmospheric origin before studies can be made of the smaller variations of the primary cosmic ray intensity.

In this thesis an attempt has been made to remove the variations of atmospheric origin from the cosmic-ray intensity recorded simultaneously by a neutron monitor and a meson telescope located at Albuquerque, New Mexico. It was found that the neutron …

Electron Energy Dissipation, E. J. Kobetich, Robert Katz

Robert Katz Publications

A new algorithm for the computation of the energy dissipated by normally incident, monoenergetic electron beams, provides good agreement with experimental data and with the computations of Spencer.

Projected Hartree Product Wavefunctions. Ii. General Considerations Of Young Operators, Gordon A. Gallup

Gordon Gallup Publications

A discussion is given of the forms of two specific and one general Young operator for the irreducible representations of S_n important for fermion space functions. Comparisons are made of the projected Hartree product version of Löwdon's projected Hartree–Fock method with CI calculations. ©1969 American Institute of Physics

Projected Hartree Product Wavefunctions. Iii. Comparison With The Ci Method For H2, R.C. Morrison, Gordon A. Gallup

Gordon Gallup Publications

Calculations of the energy of H₂ have been performed using both the projected Hartree–Fock (PHF) method and a full CI method in the same basis for comparison of the two methods. It is discovered that PHF can account for 86% of the correlation energy, whereas CI will account for 88% of the correlation energy. ©1969 American Institute of Physics

Quasifree Knockout Of Deuterons In The ⁶Li(Α,Αd)⁴He Reaction At 23.6 Mev, K. Bähr, T. Becker, Oleksa-Myron Bilaniuk, R. Jahr

Physics & Astronomy Faculty Works

α−d correlations in quasi-elastic scattering of 23.6-MeV α particles on the deuteron cluster of the ⁶Li target were measured in and off the principal reaction plane. Despite the low c.m. energy of 14.2 MeV, the impulse approximation provides a reasonable description of the quasifree process. Computations were based on the asymptotic α−d S-state wave function and on the cluster-model wave function of ⁶Li. Insensitivity of the fits to the details of the ⁶Li cluster-model wave function indicates an extreme surface reaction mechanism. The full width at half-maximum of the spectator momentum distribution was found to be 48±6 MeV/c. By comparing …

Absence Of Induced Magnetic Fields At Gd Nuclei In Gdfe2, H. Maletta, Richard B. Frankel, W. Henning, R. L. Mössbauer

Physics

Measurements of the magnetic hyperfine field at ¹¹⁵Gd in GdFe₂ in external magnetic fields reveal the absence of induced magnetic fields, in disagreement with other reported data.

Application Of The Method Of Lattice Statics To Vacancies In Na, K, Rb, And Cs, John W. Flocken, John R. Hardy

John R. Hardy Papers

We have calculated the lattice distortion produced by a single vacancy in Na, K, Rb, and Cs. The calculations have been carried out using the technique of lattice statics, which is based on the Fourier transformation of the direct-space equilibrium equations, making consistent use of discrete lattice theory. Three distinct types of potential have been used to describe the interactions between the host atoms. The first of these applies only to sodium, and contains an ion-electron-ion term derived from the measured phonon dispersion curves. The second applies only to potassium, and has been similarly obtained. The third is based on …

Quadrupole Moment Of 57FeM, J. Chappert, Richard B. Frankel, A. Misetich, N. A. Blum

Physics

The quadrupole splitting induced by a magnetic field at low temperatures has been measured by Mössbauer spectroscopy for Fe²⁺ in MgO; a value of +0.21 ± 0.03 barn for the quadrupole moment of ⁵⁷Fe^m is obtained.

Two-Photon Decay Of The Singlet And Triplet Metastable States Of Helium-Like Ions, Gordon W. F. Drake, G. A. Victor, A. Dalgarno

Physics Publications

The two-photon decay rates and photon energy distributions of the metastable 2S1 and 2S3 states of the helium isoelectronic sequence are calculated by variational procedures for the ions He i through Ne ix. © 1969 The American Physical Society.

Singlet-Triplet Mixing In The Helium Sequence, Gordon W. F. Drake

Physics Publications

Accurate variational calculations are presented for the off-diagonal matrix elements of the Breit interaction between the 2P1 and 2P3 states of several members of the helium iso-electronic sequence. A comparison is made with recent Z-expansion calculations, which are accurate through terms of order α2Z3. The comparison shows that the Z-expansion method for off-diagonal mixing is potentially useful in the theory of many-electron atoms. The effect of singlet-triplet mixing on the 2P3 excitation cross sections is briefly discussed. © 1969 The American Physical Society.

Equilibrium Concentration Of Impurity-Vacancy Complexes, Robert Fuller, H.B. Rosenstock

Robert G. Fuller Publications

In recent years the transport properties of alkali halide crystals have been discussed in terms of fi ve defects, i.e. isolated anion vacancies, isolated cation vacancies, isolated impurity ions, nearest neighbor vacancies of opposite electric charge (divacancies), and nearest neighbor impurity- vacancy complexes [1]. Originally these defects were treated as noninteracting particles located at appropriate lattice sites (the presence of divacancies and complexes was not assumed) and the defect concentrations were obtained from statistical mechanics. Subsequently the defects were allowed to interact with oppositely charged defects located at nearest neighbor lattice sites and the concentrations of divacancies and complexes were …

Optical Radar Observations Of The Stratosphere And Mesosphere, Douglas Parker Woodman

Dissertations, Theses, and Masters Projects

No abstract provided.

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 …

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.

Summation Over Feynman Histories In Polar Coordinates, David Peak, A Inomata

All Physics Faculty Publications

Use of polar coordinates is examined in performing summation over all Feynman histories. Several relationships for the Lagrangian path integral and the Hamiltonian path integral are derived in the central‐force problem. Applications are made for a harmonic oscillator, a charged particle in a uniform magnetic field, a particle in an inverse‐square potential, and a rigid rotator. Transformations from Cartesian to polar coordinates in path integrals are rather different from those in ordinary calculus and this complicates evaluation of path integrals in polars. However, it is observed that for systems of central symmetry use of polars is often advantageous over Cartesians.

A Glance At The Showmanship Of Physics, John E. Savage

Honors Theses

"Teachers should present dramatic demonstrations of scientific principles and involve students in them. They should dispense fewer facts, ask more questions, and stir the intellect. Then the students will puzzle out the answers and remember them," says Professor Julius Sumner Miller of El Camino College in Southern California. "Remember this! If you're dead, and the text book is dead, you'll have dead students."

The classic example of the intellect being stirred by dramatic demonstrations took place in London when Sir Humphrey Davey gave the Christmas Lectures. Believe it or not, people paid to hear these lectures dealing with natural· physical …

A Determination Of The Speed Of Light By The Phase-Shift Method, John Rogers, Ronnie Mcmillan, Robert Pickett, Richard A. Anderson

Physics Faculty Research & Creative Works

A low-frequency, phase-shift method for the measurement of the speed of light has been developed. This technique gives results commensurate with other advanced laboratory methods. One advantage of this technique is that the apparatus is of reasonable size and most of the circuitry involves widely known amateur radio techniques. Furthermore, our use of a low modulating frequency permits use of the solid-state, electro-optical light shutter. This eliminates the rather dangerous liquid Kerr cell, thus making our apparatus more acceptable to application in the undergraduate advanced laboratory. From a pedagogical point of view, the student is allowed to use and become …

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 …