Physical Sciences and Mathematics Commons^™

A Numerical Solution To The Problem Of Rotation Near The Ground, David D. Chen

Mechanical & Aerospace Engineering Theses & Dissertations

No abstract.

Analytic Approach To Electron Correlation In Atoms, Ronald White, Frank Stillinger

Center for Advanced Mineral and Metallurgical Processing (CAMP)

A novel perturbative treatment of electron correlation in N‐electron atoms is devised. The unperturbed starting point is a central‐force “hydrogenic” problem in the full dN‐dimensional configuration space (d = dimensionality). The central potential in this solvable “hydrogenic” problem is obtained by averaging the actual electron–electron and electron–nucleus potentials over all dN − 1dN − 1 hyperspherical polar angles in the configuration space. The relevant projected Green's functions are computed for the ground states of the model one‐dimensional two‐electron atom (with delta function interactions), as well as for the real three‐dimensional helium isoelectronic sequence. The corresponding first‐order wavefunctions exhibit weakly singular …

-Ray Induced Luminescence Of Ruby, Wayne Cooke

Masters Theses & Specialist Projects

Since the advent of the laser there has appeared a multitude of scientific papers describing the various parameters that would affect the lasing action of the ruby laser. Many investigations have been carried out to determine the efficiency of the R-line fluorescence in ruby: however very little work has been done concerning the X-ray-induced luminescence of ruby.

Certainly the applications to laser technology would be of sufficient importance to merit a study of ruby under continuous irradiation, although this was not the main stimulus that motivated this investigation. The original program of study was undertaken to determine if there existed …

Propagation Of Ultrasound In Plastic Crystals, Carl E. Scheie

Physics & Astronomy ETDs

The study of the organic solid state, and in particular of plastic crystals, is a relatively new branch of physics (1,2). Timmermans first surmised the existence of these solids from the anomalous values of the entropies of fusion. The solids possess many of the characteristics of liquids. They are easily deformed by pressure and they show dielectric properties that can be described on the basis of rotation of the molecules in their lattice positions. Still they have a definite crystal structure. Thus, even though the molecules are not symmetric, they appear to be to some degree because of the rotation. …

Hot Electron Injection Into Liquid Argon From A Tunnel Cathode, Pavel Smejtek, David G. Onn, M. Silver, P. Kumbhare

Physics Faculty Publications and Presentations

Hot electrons from a tunnel cathode have been injected into liquid argon (99.998% pure) at 87°K. The current vs voltage characteristics indicate that the injected hot electrons thermalize very slowly, losing their energy only by elastic scattering processes and finally by capture by the dilute impurities. The deduced thermalization time and distance are very long compared with that in helium, where bubble formation is responsible for energy loss.

Asymptotic Behavior Of Fluid Jets, Ronald Walter Godfrey

All Master's Theses

In this paper we shall consider the steady-state, two dimensional, irrotational flow of an inviscid, incompressible fluid under gravity.

An Investigation Of A Gas Measurement Technique Employing Ultraviolet Excitation, Alphonso Vincent Diaz

Physics Theses & Dissertations

A study was undertaken to determine the general applicability of a temperature measurement technique which uses the fluorescence stimulated by a vacuum ultraviolet continuum as the indicator. This study was directed toward determining the temperature of nonradiating carbon monoxide. A number of ultraviolet radiation sources which produced high intensity in the region of l,150 A were investigated. This study led to the conclusion that the technique was not applicable to measurements in carbon monoxide within the present limits of' detectability.

Elastic Scattering Of 1.33 Mev Gamma Rays From Uranium, Joan Sue De Vries

Masters Theses

No abstract provided.

A Study Of Defects In Platinum Using Positron Annihilation, Clarence D. Esseltine

Masters Theses

No abstract provided.

A Direct Measurement Of The Ratio Of The Reaction Cross Sections For Two-Photon And Three-Photon Annihilation Of A Positron And An Electron In Aluminum, Jeffrey Ira Siegel

Masters Theses

No abstract provided.

Calculations Of The Intensity Of X-Ray Diffuse Scattering Produced By Point Defects In Cubic Metals, John W. Flocken, John Hardy

John R. Hardy Papers

We have calculated isointensity profiles for the diffuse x-ray scattering associated with certain types of defects in Cu, Al, Na, K, Li, and a theoretical model lattice. These profiles were computed for high-symmetry planes very close to reciprocal-lattice points of the (S, 0,0), (S,S,0), and (S,S,S) type. Both cubic and double-force defects were treated. The calculations were done using a technique presented by Kanzaki for the theoretical model lattice. Kanzaki's general conclusion that cubic defects produce leminiscate profiles and that double-force defects produce ellipsoidal profiles is confirmed for all the material studied. Our profiles for the model lattice agree with …

Asymptotic Lattice Displacements About Point Defects In Cubic Metals, John W. Flocken, John R. Hardy

John R. Hardy Papers

We have calculated the asymptotic displacements (a) about a single vacancy in Al, Na, K, and Li, (b) about a single interstitial Cu atom in a Cu host lattice, and (c) about a unit single double force along a (100) direction in A1 and Cu. These calculations were made using the asymptotic equations of the method of lattice statics which, in its full form, is based on the Fourier transformation of the direct-space force equations between the detect and the host atoms in a large "supercell" of the lattice. Results were also obtained for each of the defect types in …

Stress-Induced Angular Momentum Quenching In Mgo: Fe2+ As Observed By Mössbauer Spectroscopy, J. Chappert, A. Misetich, Richard B. Frankel, N. A. Blum

Physics

Under the influence of a suitable uniaxial stress, the quenching of the electronic angular momentum of the low-lying threefold degenerate Γ_5g level of Fe²⁺ in cubic MgO has been observed by Mössbauer spectroscopy. The result is consistent with Ham's model for the appearance of a quadrupole doublet at low temperatures. A value for the strain coefficient of Fe²⁺ in MgO has been obtained: G₁₁=585 cm^-1.

Rayleigh Hysteresis Shape: Its Relationship To Displacement Distance Of A Single Domain Wall In 50% Ni–Fe, R. C. Woodbury, M. R. Hunt

Faculty Publications

The need to measure the displacement distance of domain walls from equilibrium for very weak alternating fields (H ≪ coercive force) in bulk magnetic material has prompted a study of the possible use of the opening of the Rayleigh hysteresis loop to indicate the amount of wall displacement. This paper contains (1) a review of the theoretical relationship between hysteresis shape and the displacement distance of a domain wall, based upon defect-energy models of Rodbell and Bean, and Baldwin; and (2) an experimental approach which provides a measure of the wall displacements versus hysteresis shape for 50% Ni–Fe tape. Discrepancies …

Existence Of Fixed Poles And Their Role In Conspiracy, Paul Finkler

Paul Finkler Papers

It is shown that unitarity allows fixed poles at certain nonsense points of either right or wrong signature. The conditions for the existence of these poles are found. These conditions are then used to locate the poles allowed in hadronic reactions. Possible mechanisms for the poles are considered. It is then argued that fixed poles provide the most natural explanation of the conspiracy phenomenon.

Fermi Surface Of Ausb2. I. High-Field Galvanomagnetic Effects, J. Ahn, David J. Sellmyer

David Sellmyer Publications

High-field galvanomagnetic effects have been investigated in the pyrite structure metallic compound AuSb₂ in fields up to 150 kG. The resistance ratios of the samples [ρ(295°K)/ρ(4.2°K)] were as high as 520. The results indicate that AuSb₂ is a compensated metal and that its Fermi surface supports open orbits in 〈100〉, 〈110〉, and 〈112〉 directions. At fields higher than about 50 kG, the tendency toward saturation caused by the open orbits changes to a field dependence approaching quadratic, and rather large-amplitude quantum oscillations in the magnetoresistance appear. This behavior is explicable in terms of a loss of the open …

Time Saving In Measurement Of Nmr And Epr Relaxation Times, David C. Look, Donald R. Locker

Physics Faculty Publications

By producing a train of absorption or dispersion signals (continuous‐wave magnetic resonance) or free induction decays (pulsed magnetic resonance) it is possible to save time in spin‐lattice relaxation measurements due to the fact that it is not necessary to wait for equilibrium magnetization before initiating the train. The relaxation time may be calculated from the train according to a simple rapidly converging iteration.

Proposed Thermodynamic Pressure Scale For An Absolute High-Pressure Calibration, Daniel L. Decker, J. Dean Barnett

Faculty Publications

The field of high pressure has developed rapidly over the past few years to a point where relatively sophisticated experiments are being attempted. In many experiments it is no longer sufficient to qualitatively estimate the pressure or to base conclusions on experimental results tied to an empirical pressure parameter. One desires to accurately know the pressure dependence of physical quantities related to a true thermodynamic scale.

Differential Cross Section For Charged A₁ Photoproduction Using The Regge Exchange Formalism, Keiji Kikkawa, Barbara N. Hale

Physics Faculty Research & Creative Works

The Regge-pole formalism is applied to the calculation of the differential cross section for A₁⁺ photo-production in the region |t_min| < -t < 10µ². The p, A₁, A₁-daughter, A₂, and π trajectory contributions are considered, and use is made of chiral dynamics to estimate the unknown coupling constants. We find that the π and the A₂ trajectories provide the dominant contributions.

Projected Hartree Product Wavefunctions. Iv. Radial Correlation In Some Three- And Four-Electron Atoms, L.G. Heikes, Gordon A. Gallup

Gordon Gallup Publications

The energies of some three- and four-electron atoms including radial correlation have been determined by a spin-free version of the projected Hartree–Fock method. The wavefunction possesses the maximum flexibility allowable under the general restrictions of the method, and it is shown that this flexibility is necessary to adequately account for the differences between intra- and intershell correlation. Some comments on the AMO method are included. ©1970 American Institute of Physics

Projected Hartree Product Wavefunctions. V. Density Matrices And Operators Containing Spin, Gordon A. Gallup

Gordon Gallup Publications

Formulas are given to allow the calculation of the various spin components of the first-order density and transition density matrices from one spatial component of a pure spin-state wavefunction and certain reduced operators. Similar expressions are given for the second-order density for singlet and doublet systems. These results are useful for the calculation of matrix elements of operators containing the spin. ©1970 American Institute of Physics

Measurement Of Cyclohexane Ultrasonic Velocity Using Photon-Phonon Scattering Interactions, Edward W. Taylor Jr.

Physics & Astronomy ETDs

The construction of a frequency modulated optic cell and its operation for studying the ultrasonic velocities of cyclohexane, acetone and ethyl alcohol as a function of temperature is described. A description of photon-phonon scattering interactions is presented. The appearance of the intensity distribution of the scattered light is treated, and an analysis of the experimental results is included. The special scattering case of Bragg diffraction of coherent light was used for determining the ultrasonic velocities of cyclohexane as a function of temperature. Ramifications of the Raman-Nath and Bragg diffraction effects are discussed. The relationship v_T = 1376.78 - 5.25 …

2p2 P3 And 2p3p P1 States Of The Helium Isoelectronic Sequence, Gordon W. F. Drake, A. Dalgarno

Physics Publications

Accurate eigenvalues and radiative lifetimes are obtained for the bound 2p2 P3 and 2p3p P1 states of the heliumlike ions He i to Ne ix. A high-order Z-expansion perturbation procedure is used that does not require the explicit solution of perturbation equations. The results are compared with variational calculations. The predicted wavelengths of the 1s2pP3-2p2 P3 and 1s3pP1-2p3pP1 transitions in helium are, respectively, 320.31 and 308.97 Å. Lines have been observed in helium at 320.39 and 309.04 Å. © 1970 The American Physical Society.

Emission Of Auger Electrons Resulting From Symmetric Argon And Neon Ion-Atom Collisions, R. K. Cacak, Q. C. Kessel, M. Eugene Rudd

M. Eugene Rudd Publications

Cross sections for the emission of Auger electrons from excited atoms and ions produced in symmetric Ar⁺-Ar and Ne⁺-Ne collisions have been measured at ion energies from 50 to 300 keV. A simple model is proposed to explain the dependence of the cross section on the impact energy; the predicted results agree well with the experiment. Also, the argon x-ray data of Saris and Onderdelinden are compared with the model and with the results of this experiment.

On The Relation Between Hard-Core And Velocity-Dependent Potentials: An Application To The Photonuclear Sum Rules, Paul Finkler, H. S. Valk

Paul Finkler Papers

A canonical transformation relating hard-core and velocity-dependent nucleonnucleon potentials is applied to the Srivastava potential and an equivalent hard-core potential is found. It is shown that the deuteron photonuclear electric-dipole integrated and bremsstrahlung-weighted cross sections resulting from the two equivalent potentials are essentially the same. The reasons for this agreement suggest that differences between the two sets of cross sections may remain small in other nuclei employing this type of potential.

Response Of Nuclear Emulsion To Electron Beams, Robert Katz, E. J. Kobetich

Robert Katz Publications

A recent theory of particle tracks assumes that the probability P for grain development in nuclear emulsion depends on the local dose E of ionization energy deposited by secondary electrons (delta rays) in the neighborhood of the particle track. The response is assumed to be one of exponential survival; that is, if E₀ is the dose for 37% survival, then P = 1 – exp (-E/E₀). By calculation of the dose E(t) deposited at depth t in the emulsion by normally incident, monoenergetic electron beams, and applying the assumed dose-effect relationship, …

Formation Of Particle Tracks, Robert Katz, E. J. Kobetich

Robert Katz Publications

The formation of particle tracks, and such phenomena as the detection of charged particles and the damage produced by charged particles, are intimately related to the spatial distribution of ionization energy deposited by δ-rays. Changes in the spectrum of δ-rays with the velocity of the primary particle imply that linear measures of the interaction of the primary particle with the medium, such as specific energy loss, or primary ionization, are unsatisfactory measures of effects produced in the medium, for they contain no knowledge of the spatial deposition of the lost energy.

On The Physical Properties Associated With Omega Phase In Titanium-Chromium Alloys, Serag El Din El Sayed Habib

Archived Theses and Dissertations

No abstract provided.

Investigation Into The Monotonic Magnetostriction And Magnetic Breakdown In Cadmium, James Milo Carter

Doctoral Dissertations

"Observations of the monotonic magnetostriction of cadmium at 4.2 K and in fields of 65 kilogauss have been made. The angular dependence of an extremal point (H_m) in the monotonic magnetostriction is found to follow inverse cosine behavior. The magnitude of H_m (27 kG) for fields parallel to [0001] is in fair agreement with the onset of γ_1/3 from the breakdown of the trifoliate orbit, γ. The range of observation of h_m coincides with the reported range of the trifoliate orbit. A "klink" in the monotonic magnetostriction is demonstrated. The "klink" field, H_k, …

Absolute Excitation Cross Sections Of He⁺ In 20-100 Kev He⁺-He Collisions Using Energy-Loss Spectrometry, Donald Roy Schoonover

Doctoral Dissertations

"Application of positive-ion energy-loss spectrometry has been extended to include experimental determination of absolute excitation cross sections of ground state helium ions. Helium ion-atom collisions were studied for impact energies ranging between 20-100 keV, in 10 keV intervals. The data were taken with an apparatus resolution between 0.6-o.8 eV FWHM. Cross sections for transitions from ground state to the second and third principal quantum levels of the ion plotted as a function of impact energy were still rapidly increasing at 100 keV. The cross sections at this energy were 1.64(± 0.28) x 10⁻¹⁸cm² for He⁺(l²s_1/2) -> He⁺(n = …