Physical Sciences and Mathematics Commons^™

Optical And Electron-Paramagnetic Resonance Studies Of Sodium-Fluoride, Ronald Allen Andrews

Wayne State University Dissertations

No abstract provided.

Simulated Radioactivity, Robert Katz, J. J. Butts

Robert Katz Publications

An experiment to simulate radioactive decay is easily performed with a random-number generator or a set of random numbers. The nuclei are imagined to be indexed consecutively. The initial appearance of the index number of a particular nucleus is interpreted as a signal that it has disintegrated. The number of surviving nuclei is an exponential function of the number of draws, and represents the radioactive decay law, with fluctuations. This procedure is a precise realization of the conventional probabilistic derivation of the radioactive decay law if, indeed, the random number generator is truly unbiased.

On The Symmetry Of Slater Determinantal Wavefunctions, Gordon A. Gallup

Gordon Gallup Publications

A method involving the use of characteristic polynomials of irreducible representation matrices of groups and yielding the symmetry species of Slater determinantal functions is given. The necessary polynomials have been calculated for the commonly occurring symmetry groups and are listed to supplement the usual character tables. ©1966 American Institute of Physics

Model Of Electron Correlation In Solids, Everett G. Larson, Walter R. Thorson

Faculty Publications

The usual Hartree-Fock model (energy-band theory) does not always give an adequate description of electronic structure in a solid, because it ignores the effects of electron correlation. It was shown first by Wigner that such a situation always develops in an electron ''gas'' at sufficiently low density; a solid structure described by ''resonance'' of Heitler-London pair bonds between electrons localized on neighboring atoms is then a good model of the system.The transition from a Bloch-type state to such a highly correlated state as a function of electron density (lattice parameter) is a problem of considerable interest for the theory of …

8th Annual Meeting Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 8th 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 8-9, 1966.

Study Of Some Solutions Of The One-Electron—Two-Center Problem For Heteronuclear Cases, L.Y. Wilson, Gordon A. Gallup

Gordon Gallup Publications

The Schrödinger equation for two nuclei and one electron has been solved for the first eight σ states of the system HeH^{2 +} , He₂³⁺, LiH^{3 +} , and LiHe^{4 +} . The resulting solutions are described and some of their properties are discussed. ©1966 American Institute of Physics

Self-Consistent-Field Calculation Of The Energy Of Heh +, Gordon A. Gallup, M.S. Mcknight

Gordon Gallup Publications

The use of the exact solutions of the one-electron—two-nucleus problem as a basis set of functions for SCF calculations is investigated for the HeH ⁺ ion. The calculations are made with both scaled and non-scaled functions. The best energy obtained here is –3.345 a.u. at an internuclear distance of 1.40 a.u. The conclusion is that these functions form an only moderately good basis set for such calculations. Their conditioning to the problem can only partially overcome their lack of completeness when continuum states are omitted. ©1966 American Institute of Physics

Pressure Calibration To 100 Kbar Based On The Compression Of Nacl, R. N. Jeffrey, J. Dean Barnett, H. B. Vanfleet, H. Tracy Hall

Faculty Publications

An independent determination has been made of the transformation pressures assigned to the high-pressure transformations in Ba and Bi which are generally used for calibration points. The metals were imbedded in NaCl, and the transitions were detected by the resistance change of the metal while the NaCl lattice parameter was simultaneously measured by x-ray diffraction. The NaCl compression values determined at the fixed points were related to pressure by reference to the semiempirical compression curve of Decker. The Ba I-II and Bi III-V transformations at room temperature were assigned thermodynamic equilibrium values of 53.3 ±1.2 kbar and 73.8 ±1.3 kbar, …

Geometrical Representations Of Relativistic Motion, Jeffrey H. Robbins

Physics & Astronomy ETDs

This investigation begins with the development of a transformation or mapping in velocity space of such a character that velocities are mapped into a quantity that adds linearly, while velocities add non-linearly according to the Einstein Law of Addition, and has no upper limit to its magnitude, i.e., when the speed of an object approaches that of light in a vacuum, this quantity becomes infinitely large. Kinematic relationships, in Newtonian form, for a particle undergoing acceleration, are developed in a frame of reference that remains attached to the particle using the new variable (W). It is found that relativistic energy …

Angular Distribution Of Neutrons In Atmosphere Produced By Protons, Donald Stuart

Physics & Astronomy ETDs

In connection with the balloon flown directional neutron detector experiments in progress, the following theoretical problem presented itself. Find the angular distribution of neutrons incident upon a detector. This is investigated under varying conditions using a computor program prepared for this problem. Two models for the problem are considered in this paper. In the first model we choose the simplest conditions that approximate a possible physical situation. This consisted of considering that the system was completely isotropic. For certain altitudes this gave very good results as can be seen by the curves. Then modifications to the theory are discussed. This …

Investigation Of Propagation Of Light Through Gases And Air Structures Treated As Wave Guides., Richard W. Christiansen

Physics & Astronomy ETDs

The equations defining the propagation of electromagnetic radiation down cylindrical dielectric wave guides are developed. A Helium-Neon laser is used to illuminate several different cylindrical wave guides. The propagation nodes are recorded on photographic plates. Using the field equations, the electric field on a transverse plane is plotted and used to explain some HE_im modes observed. The patterns recorded on the photographic plates are described and discussed in terms of the propagation modes.

Coulomb Excitation Of The Ytterbium Isotopes., John M. Palms

Physics & Astronomy ETDs

Coulomb excitation studies have been performed on the ytterbium isotopes 171, 172, 173, 174, and 176 using oxygen ions having energies up to 55 MeV. Resulting de-excitation gamma rays have been observed in particle coincidence with a NaI(Tl) detector and as single spectra with a Ge(Li) detector. The ground state rotational bands of the Yb171 and Yb173 isotopes have been excited to the 13/2- level. The 13/2- and 11/2-levels of both nuclei have not been reported before. In addition to the transitions from the ground state band, gamma rays were observed from Yb171 and Yb173 coming from other bands. A …

Measurements Of Continuous X-Ray Spectra With A Scintillation Spectrometer, Ellery Strom

Physics & Astronomy ETDs

Scintillation spectrometer measurements were made of the x-ray spectra produced by a constant-potential x-ray unit operating at 100, 150, 200, 250, and 300 kV. An attempt was made to measure the absolute intensity as well as the spectral distribution. In order to reduce the counting rate to a measureable level, it was necessary to place the thallium-activated sodium-iodide detector 50 meters from the target. Since the air attenuation was quite large, measurements were made both in air and in helium. In order to contain the helium, an Orangeburg pipe was employed, and its effect on the spectra was determined by …

High Frequency Scattering From A Schroedinger Square Well, Robert R. Thede

Physics & Astronomy ETDs

Many observations have been made of the enhanced back scattering of light waves from water droplets. This phenomenon, commonly referred to as the glory, is inexplicable in terms of ray optics. Calculations based upon the Mie series solution to the scattering of an electromagnetic plane wave from a dielectric sphere suggest that this pronounced scattering is due to surface waves which travel around the sphere and are emitted in phase preferentially in the forward and backward direction. These results have also been verified experimentally by examining the backscattered light from a water droplet.

X-Ray Diffraction And Electron Microscopy Studies Of Glasses Containing Antimony, Sadek Momtaz Tadross

Archived Theses and Dissertations

No abstract provided.

Simultaneous Movement Of Water And Herbicides In Unsaturated Soils, Ming-Shyong Yang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Since weed killers were developed in the early part of the decade beginning in 1940, herbicides have been increasing in use until they are now widely used to control weeds. The application of herbicides has thus become a regular agricultural and ecological practice.

Simultaneous Flow Of Heat And Water In Plant Tissue, Gaylon Sanford Campbell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Although biological phenomena may be partially described in a general way without the use of mathematics and physics, the experimental results may be more meaningful if they are analyzed on the basis of physical and mathematical laws. The complexity of biological systems has made the application to them of mathematics and physics rather difficult, and only recently has much progress been made. Although it has yet been possible to describe only a few simple biological systems by actual equations, a great deal of qualitative information may be obtained by applying physics and mathematics. Russell (1960, p. 439) said

In principle …

Ferromagnetic Metals In High Magnetic Fields, A. J. Freeman, N. A. Blum, S. Foner, Richard B. Frankel, E. J. Mcniff, Jr.

Physics

High‐field susceptibility results are presented for Mössbauer measurements on iron at low temperatures in fields up to 135 kOe and magnetization measurements on iron and nickel single crystals in fields up to 148 kOe with vibrating sample magnetometers. The Mössbauer measurements give the hyperfine field H_n= H_int− (H₀−H_DM)+ΔH, where H_int is the hyperfine field at zero applied field, H₀ is the applied field, H_DM is the demagnetizing field, and ΔH is a term which would reflect a change in the magnetization at high field, …

Hyperfine Fields And Isomer Shifts In Magnetically Ordered Europium Compounds, H. H. Wickman, I. Nowik, J. H. Wernick, D. A. Shirley, Richard B. Frankel

Physics

The Mössbauer technique was employed to study hyperfine fields in several ordered divalent europium compounds at low temperatures. The intermetallics EuCu₂, EuAl₂, and EuAl₄ were ordered at helium temperatures and the observed fields and isomer shifts were 189(8) kOe, −0.88 cm∕sec; 278(8) kOe, −0.97 cm∕sec; and 290(8) kOe, −1.14 cm∕sec, respectively. Comparison of these results and previous measurements with EuO, EuS, and Eu metal indicates a possible correlation between isomer shift and internal field. With the exception of EuCu2 the internal fields increase with increasing magnitude of isomer shift. Interpretation of this trend with a …

Isomer-Shift Measurement In W182, S. G. Cohen, N. A. Blum, Y. W. Chow, Richard B. Frankel, L. Grodzins

Physics

No abstract provided.

Diffusion Of The Chlorine Ion In Potassium Chloride , Robert Fuller

Robert G. Fuller Publications

The diffusion coefficient of the chlorine ion was measured in pure single crystals of potassium chloride and in crystals containing mole fractions of strontium chloride between 2.1 x 10^-5 and 4.69 x 10^-4. The results were consistent with the assumption that both anion vacancies and vacancy pairs contribute to the diffusion of the chlorine ion. The diffusion coefficient of the chlorine ion in pure potassium chloride was well represented by the equation D=61 exp (-2.12±0.05 eV/kT) cm²/sec from 560 to 760 °C. The anion-vacancy contribution to the chlorine-ion diffusion coefficient in pure …

X-Ray Diffraction Studies On Tin To 100 Kilobars, J. Dean Barnett, Vern E. Bean, H. Tracy Hall

Faculty Publications

The high-pressure equilibrium phase diagram of tin is investigated, and the crystal structure of Sn II at 98 kbar and 25degrees C is shown to be body-centered tetragonal with a=3.70 Angstroms, c=3.37 Angstroms, c/a=0.91, and with two atoms per unit cell. The linear compressibility of white tin is given at 25degrees C up to the high-pressure transformation at 92 kbar, and the latent heat of the transformation is measured as 225 cal/g-atom.

Magnetic Structure Of Ga2−Xfexo3, R. B. Frankel, N. A. Blum, S. Foner, A. J. Freeman, M. Schieber

Physics

High‐magnetic‐field‐Mössbauer and magnetic‐moment experiments have been performed with Ga2−xFexO3. This magnetic system is of considerable interest because it is piezoelectric, weakly magnetic,1 and magnetoelectric.2 The crystal structure has been determined3 and a magnetic ordering inferred.3 The magnetic‐moment measurements were made using a vibrating sample magnetometer in fields up to 75 kOe. The samples used for the Mössbauer absorption experiments consisted of 57Fe enriched powders, grown from a flux, embedded in lucite, and having x=0.8 and 1.2. A mosaic absorber made of small x‐ray oriented single crystals was also studied. Measurements were made over the temperature range 4.2° to 320°K and …

Analog Plotting System For Recording Energy Spectra Of Low Energy Charged Particles, M. Eugene Rudd

M. Eugene Rudd Publications

During recent measurements of energy spectra of electrons emitted from gases under positive ion bombardment an analyzing and plotting system was developed which has some unique features. Utilizing an electrostatic analyzer, it sweeps over the desired energy range and plots a graph directly in electron volts. With suitable modifications it could also be used for positive ions. Energies from near 0 to about 1000 eV have been plotted but this range could be extended. Usable graphs have been obtained at counting rates as low as 3 counts/sec.
Compensation is provided for fluctuations in the signal due to slow or rapid …

Electron Energy Spectrum From Ar+-Ar And H+-Ar Collisions, M. Eugene Rudd, T. Jorgensen, Jr., D. J. Volz

M. Eugene Rudd Publications

Absolute differential cross sections have been measured for the ejection of electrons of various energies at 160° by argon ions and protons striking argon gas as a target. The observed energy spectrum consists of a number of "lines" or peaks superimposed on a continuous spectrum. The fine-structure regions occur below 20 eV and from about 120 to 220 eV for both projectiles. A number of lines are identified with auto-ionization transitions from neutral states and with Auger transitions from one- and two-vacancy states. With argon ions each peak has a "Doppler"-shifted counterpart due to electrons emitted from the moving particles. …

The Mössbauer Effect In Bismuth Ferrate, Bruce A. Banks

Masters Theses

"The magnetic hyperfine structure of the Fe⁵⁷ nuclei in bismuth ferrate was investigated using the Mössbauer effect. A Mössbauer effect spectrometer was built with consideration given to the elimination of vibration and the optimizing of the source, absorber, and detector geometries to produce the largest fractional Mössbauer effect per fractional standard deviation. The internal magnetic field at the Fe nuclei in BiFeO₃ was determined to (482 ± 9) kilooersteds at room temperature"--Abstract, page ii.

Observation Of Doppler-Shifted Peaks In The Energy Spectrum Of Autoionizatioin Electrons From Ar+ -Ar Collisions, M. Eugene Rudd, T. Jorgensen, Jr., D. J. Volz

M. Eugene Rudd Publications

It is well known that when heavy ions traverse gas, electron pickup into excited states occurs. If the fast excited atom subsequently decays by radiating a photon, the energy of the photon will be Doppler shifted due to the motion of the source. This effect may be used to distinguish the radiation from stationary and moving atoms. For example, this method was used by Meinel to deduce the motion of solar protons streaming downward through the earth's atmosphere.
If instead the moving atom decays by autoionization, the ejected electron should also show a shift in energy analogous to the Doppler …

An Experimental Study Of The Back Scattering Of Coherent Light From Falling Water Drops., William Ogle

Physics & Astronomy ETDs

Introduction

The purpose of this study is to make a statistical investigation of the backscattering of light from freely falling water drops, and to determine if the surface wave is a significant contribution to the backscattered intensity from large drops.

The Faraday Rotation And Dispersive Doppler Effects In The Ionosphere At Oblique Incidence, Charles Roland Baugher Ii

Masters Theses

"Integral equations for the isotropic and anisotropic ray path of a radio wave propagating through the ionosphere are developed. These equations assume a spherically stratisfied ionosphere and are equivalent to a detailed ray-tracing process. A method is devised to utilize these equations in the evaluation of combined Faraday rotation and dispersive Doppler data from earth satellites for subionospheric electron content. The method, which corrects for horizontal ionospheric gradients, is applied to data from the Explorer 22 satellite and some preliminary results are discussed"--Abstract, page ii.

The Construction Of A Multi-Threshold Foil For Fast Flux Measurements, Michael Henry Holkenbrink

Masters Theses

"The construction of a multi-threshold foil for fast neutron flux measurements is investigated. The factors governing the selection of the materials are the energy response of the given reactor, the half-life of the daughter, the prominent gamma ray emitted during decays, the power level of the reactor, the availability of adequate cross section data, and the alloying properties of the composite foil. A ternary system was chosen as a compromise between the difficulty of fabrication and the amount of information gained from one foil. The particular system chosen was In- P- Fe. The threshold reactions of these elements are In¹¹⁵ …