Physical Sciences and Mathematics Commons^™

The Statistics Of Finite, One Dimensional Lattice Fluids, John Roger Glaese

Doctoral Dissertations

"A one dimensional lattice fluid in which particles are allowed to assume only discrete positions is proposed. Particles are free to move from one lattice site to another interacting through a variety of potentials, including the Lennard-Jones type. The model allows the partition function to be evaluated as a discrete sum over the allowable configurations. Both the canonical ensemble and grand ensemble are treated by computer and a third, the pressure ensemble, is considered and shown to be useful in the theoretical treatment of lattice systems. The thermodynamic behavior of various systems is investigated in both the canonical and grand …

A.C. Hall Effect Measurements On Very High Resistivity Materials Exhibiting Electrode Polarization, James Dale Boyd

Doctoral Dissertations

"A variable frequency, a.c. Hall effect measurement technique has been designed for mobility studies in very high resistivity (>10⁹ ohm·cm) materials exhibiting electrode space charge polarization effects. It incorporates a neutralized input capacitance preamplifier detector which reduces the total input shunting capacitance, including the sample interelectrode capacitances, to a very low, definable value (<0.1 pf) and thereby provides very high and well defined a.c. detector input impedances (4 x 10⁹ and 7 x 10⁹ ohms at 600 and 200 Hz, respectively). Lumped parameter equivalent circuits have been defined to approximate the electrical behavior of sample materials in the measurement configuration. These equivalent circuits, together with independent measurements of the detector input and sample impedances, allow one to correct the detected Hall voltage and obtain the true value from which mobility data may be derived. The validity of these circuits has been established by independent a.c. and d.c. measurements on photoconductive CdS (dark resistivity >10¹⁰ ohm·cm) which exhibited maximum differences of less than 4%. The existing literature has been critically reviewed and the measurement criteria established by this study have been applied to resolve differences in reported data and to suggest improvements in the resolution of previously employed experimental …

Infrared Cooling Near Atmospheric Temperature Inversions And Absorber Concentration Variations, Joey Keith Tuttle

Masters Theses

"Cooling due to infrared radiation near temperature inversions is investigated. Temperature inversions tend to hold pollution below the inversion level. The pollution itself may contribute to the stability of the inversion by selectively cooling certain portions of the atmosphere. A method is developed for evaluating infrared cooling rates at discreet points in the atmosphere. Several sample calculations are given to demonstrate the effects of variations of absorber concentration and lapse rate"--Abstract, page i.

An Experimental Comparison Of Various Nuclei Counters, Joel William Mansell

Masters Theses

"A series of simultaneous nuclei concentration measurements, with four different nuclei counters, have been made. these counters were a Pollak and a Gardner counter supplied by Mr. Paul Allee of the Environmental Science Services Administration, Boulder, Colorado, and a Pollak and a G.E. counter supplied; by Mr. Norman White of the National Center for Air Pollution Control, Cincinnati, Ohio. In the absence of any knowledge of the absolute concentrations in the samples, the data for each of the individual counters have been compared to the averages computed from all four counters. The results of these comparisons indicate the following: (1) …

Vapor Phase Clustering Model For Water, Richard W. Bolander

Doctoral Dissertations

"Although nucleation phenomena are among the most widespread of all naturally occurring phenomena, even the simplest of nucleation processes, homogeneous nucleation, is poorly understood, particularly the homogeneous nucleation of liquid droplets from water vapor. Homogeneous nucleation involves only molecules of a single substance and does not include the complicating effects due to a substrate or piece of foreign matter. The semiphenomenological liquid drop theories developed nearly three decades ago differ in relatively minor details, with the crucial element of the theory being the derivation of the free energy of formation of the clusters. The clusters are viewed as well-defined incompressible …

Low-Lying Levels In Some Spherical And Rotational Nuclides By Coulomb Excitation And Radiative Capture Of Thermal Neutrons, Donald Allan Mcclure

Doctoral Dissertations

"The work presented in this dissertation was performed in order to obtain additional information on the level schemes and decay properties of several nuclei in an attempt to explain the observations in terms of an applicable nuclear model. Various nuclear models are discussed in Section II. A general review from the classical point of view of the Coulomb excitation reaction is discussed in Section III and the thermal-neutron-capture reaction is outlined in Section IV. The experimental equipment and procedure is discussed in Section V in which the ramper method of energy determination is outlined. This method allows the measurement of …

MöSsbauer Effect Studies Of Ferroelectric Phase Transitions In The Pbzro₃ - Pbtio₃ - Bifeo₃ Ternary System, James P. Canner

Doctoral Dissertations

"The Mössbauer Effect was used to measure the phase transitions in the following ferroelectric compounds: 95% PbZ4₀.₈Ti₀.₂ - 5% BiFeO₃ [and] 95% PbZ4₀.₇Ti₀.₃ - 5% BiFeO₃ and in the antiferroelectric compound: 95% PbZrO₃ - 5% BiFeO₃. The parameters obtained were the area under the resonance peak, the isomer shift, and the electric quadrupole splitting, all as a function of temperature. The ionicity, electric field gradient, and Debye temperature were determined for room temperature. The data are discussed in terms of the lattice vibration model of ferroelectrics and antiferroelectrics, and the structural phase transitions as recently defined for these compounds. The …

Radiative Lifetime Of The B¹Σ⁺ And B³Σ⁺ States Of Carbon Monoxide, John Robert Rogers

Doctoral Dissertations

"The radiative lifetimes of the B¹Σ⁺ and b³Σ⁺ excited states of carbon monoxide were measured at six different pressures: 10, 25, 50, 75, 100, and 125 microns of Hg. The lifetimes were obtained by observation of the radiative decay of the (0,0), (0,1), (0,2), and (1,1) bands of the Angstrom system and the radiative decay of the (0,1), (0,2), (0,3), and (0,4) bands of the Third Positive system. No pressure dependence of the lifetimes was observed for either system. The average lifetime of the v' = 0 vibrational level of the B¹Σ⁺ state was found to be 24.4 x 10⁻⁹ …

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 …

A Study Of The Evaporation Rates Of Small Freely Falling Water Droplets, Hugh Alan Duguid

Masters Theses

"The evaporation rates of small (radium 3-9µ), freely falling water droplets were determined. the droplets, produced in a diffusion cloud chamber, were allowed to fall through air of known relative humidity (95-100%) and at three ambient temperatures (25C, 30C, and 35C) in a vertical drift tube. the rates of evaporation were ascertained by recording the drop positions on film at fixed time intervals. The results are compared with several existing theories, and are found to lie between the formulation of Kinzer and Gunn, and the quasistationary theory based on Maxwell's equation"--Abstract, page ii.

Raman Backscatter Of Laser Radiation In The Earth's Atmosphere, Samuel Harvey Melfi

Dissertations, Theses, and Masters Projects

No abstract provided.

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 …

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.

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

Physics Faculty Publications

No abstract provided.

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.

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.

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. …

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.

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 …

Sunspots, James Mccarty

Honors Theses

This past semester the physics department began a study of the solar wind. Photographic plates have been sent up by balloon during periods of both maximum and minimum solar activity. The tracks made by high-energy particles on these 3mulsions are to be located and analyzed. Unfortunately, since the plates have yet to arrive, only a little practice scanning was done to become familiar with the technique. Meanwhile, an attempt has been made to gather information ab::mt the sun and the solar wind. This paper is a part of that work.

A Report Of Work For H492, Claudia Morgan Griffin

Honors Theses

My research project for this year is to study nuclear emulsion plates sent to the physics department by Dr. Davi.d Young of Mississippi State University and to learn as much as possible about the fields related to the project. These plates are exposed to cosmic rays at altitudes, for all practical purposes, above the earth's atmosphere. They are then collected and processed. They will be sent to us so that we can scan them next semester.

The first semester's part of the project was to scan a sample plate and to do· a literature research of related fields. Therefore, this …

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.