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X-Ray Diffraction Studies On Liquids At Very High Pressures Along The Melting Curve. I. Methods And Techniques, Keith H. Brown, J. Dean Barnett

Faculty Publications

A technique using the tetrahedral anvil high-pressure x-ray system has been developed to extract coherent x-ray intensity patterns of liquids near melting from measured scattering curves in the presence of high-background counts. Radial distribution functions for liquids along the melting curve to pressures of at least 50 kbar can be obtained. At each pressure scattering curves are recorded for the liquid and solid on opposite sides of the melting curve and a subtraction is made to eliminate background and incoherent scattering. Theoretical estimates of the thermal diffuse scattering from the solid are added to the appropriately corrected difference patterns to …

Lasing Conditions Of Elemental Sulfur In A Gas Discharge, David E. Egbert

Theses and Dissertations

The partial pressures from heated sulfur crystals and helium, and sulfur and nitrogen required for ionic sulfur laser action in a gas discharge were determined. Previous work with sulfur lasers is reviewed and population inversion mechanisms are presented for the ionic sulfur laser lines. Possible excitation mechanisms are presented for both electron and ion or atomic collision excitation. Transition diagrams for all the known ionic sulfur laser transitions and an approximate potential energy curve for the diatomic sulfur molecule are presented. Laser action was achieved only when a spark gap pulser was used with a laser tube especially designed to …

New Method For Generating Density Expansions, John D. Ramshaw

Physics Faculty Publications and Presentations

The calculus of finite differences is used to develop a new method for expressing the thermodynamic limit of a reasonably arbitrary statistical?mechanical average as a power series in the number density ?. The method is simple, straightforward, and purely analytic: it involves no intermediate expansion in powers of the activity and it avoids the use of graph theory. Moreover, the method is developed independently of the prescription for computing the statistical average, a fact which lends to the results an especially wide range of applicability. In particular, these results may be used in classical or quantum statistical mechanics, for intermolecular …

X-Ray Diffraction Studies On Liquids At Very High Pressures Along The Melting Curve Ii. Sodium, Keith H. Brown, J. Dean Barnett

Faculty Publications

Coherent x-ray diffraction patterns for liquid Na have been extracted from measured patterns at 0.5, 7.5, 17, and 43 kbar along the melting curve. The experimentally determined liquid structure factor and resulting radial distribution function are given at each pressure. The position of the principal x-ray intensity peak is reproducible to within 0.5% and shows shifts of the order of 12%. The resulting nearest neighbor distance in the radial distribution function also shifts 12% but is reproducible only to approximately 2%. The distribution functions obtained at points along the melting curve suggest a simple dimensional compression or scaling; however, a …

Measurements Of The Mössbauer Fraction In Chromium, B. Frederick Brace Jr.

Dissertations and Theses

Precision measurements of the Mossbauer fraction of Fe57 in chromium were made using the black absorber technique over a range of temperatures from 78K to 792K. Because of uncertainty in corrections at high temperatures, only the data collected from 78K to 600K was used in analyzing the results.

The f values were analyzed in terms of a Debye approximmation. This analysis of the data yielded a theoretical fit which was based on two adjustable parameters (a Debye temperature of 438K and an anharmonicity parameter of 2 x 10^-4K^-1).

The f measurements were also analyzed using a …

Raman Scattering From Zns Polytypes, J. Schneider, Roger D. Kirby

Roger Kirby Publications

The Raman spectra of the 2H and 4H structures of ZnS have been measured between room temperature and 60 K, and compared with the spectra from zinc blende ZnS. The observed phonons in each case are in good agreement with those expected from the known structural differences.

Frenkel Defects In Alkali Halides, Paul Schulze, John Hardy

John R. Hardy Papers

The method of lattice statics and the deformation dipole model have been applied to Frenkel defects in ionic crystals. For isolated interstitials, all short-ranged repulsive and Coulomb-defect host-lattice ion forces were evaluated at the relaxed configuration. The zero-order Coulomb force was allowed to act on the remainder of the host-lattice ions past first neighbors. We have calculated Frenkel-pair formation energies, ionic displacements, and ionic polarizations in the twelve Na, K, Rb halides. Our results show over all that, in ionic crystals of the rocksalt structure, Schottky defect pairs are more likely to be present than Frenkel defect pairs.

Nuclear-Magnetic-Resonance Study Of Co2+ In Cds, David C. Look, Donald R. Locker

Physics Faculty Publications

Nuclear spin-lattice relaxation times, T₁, have been measured over a temperature range T=(1.1-300) °K and frequency range ν=2-15 MHz in a single crystal of CdS doped with 13-ppm cobalt. Minima in T₁ vs T are observed, and absolute values of the effective electron relaxation time, τ_e, may be calculated at the temperatures of the minima, e.g., at 14 °K, τ_e=8.0×10^-8 sec. At low temperatures, T≲5 °K, τ_e is dominated by a resonant Orbach process involving the two ground-state Kramers doublets (S=±3/2 and S=±1/2) which, according to our measurements, are split by …

Eikonal Approximation For Coupled Equations For Multichannel Scattering, Rung T. Ling, Joseph C.Y. Chen, Jerry Peacher, Kenneth M. Watson

Physics Faculty Research & Creative Works

It is well known that the Glauber approximation for scattering amplitudes is obtained by applying the eikonal approximation to the Fourier transform of the transition operator. The eikonal approximation can also be applied to the coupled equations of scattering obtained by the expansion of the state function in terms of a suitable set of functions. The scattering amplitude can thus be obtained by solving the set of eikonal coupled equations. The latter approach is analyzed for a special class of channel-coupling potentials. The first-order approximation to the derived eikonal coupled equations is the eikonal Born approximation. Numerical illustrations in this …

Calculations Of Nuclear Structure Using Isospin Formalism, Roger A. Cook

Masters Theses

No abstract provided.

Hydrostatic Pressure Effects On The Epr Spectrum Of V2+: A1203 And Cr3+: A120, Charles J. Wilcox

Masters Theses

No abstract provided.

14th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 14th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, July 31 - August 1, 1972.

X-Ray Irradiation Apparatus In Which An X-Ray Source Is Energized Upon The Recording Of Irradiation Dosage Data, George S. Hurst, Norbert Thennard, Karl A. Schneider

Physics and Astronomy Faculty Patents

Apparatus for use in examining or treating patients with X-radiation or the like requires the making of a permanent record of the radiation applied. The operation of the radiation source is controlled in dependence upon the making of the record and the to radiation, or dose exposure is limited to a predetermined amount. A method is disclosed for safeguarding the patient and for producing a tangible record of the dose to which the patient is subjected.

Reducing Uncertainty, Richard C. Heyser

Unpublished Writings

Intended for audio engineers, Richard C. Heyser meant for this paper to bring attention to the misapplication of the theoretical concept, the Uncertainty Principle. Heyser argues that this concept has been "freely applied without regard to the errors which may result due to lack of understanding of its derivation."

Development Of The Oso-6 High-Energy Neutron Detector And Correlation Of Measured Solar Neutron Fluxes To Solar Flares, Frederick Young

Physics & Astronomy ETDs

In an attempt to understand certain of the high energy processes that occur in the solar and terrestrial atmospheres and the interplanetary medium a detector of 20 to 160 MeV neutrons had been designed and constructed for inclusion in the NASA Orbiting Solar Observatory, Satellite OSO-G, which was launched into a near circular orbit at approximately 500 km altitude in August 1969. Both the angle of incidence and the energy of the neutron are determined by a telescopic arrangement of four scintillation plastic counters (Pilot B; hydrogen to carbon ratio 1:1) which generates proton recoils and provides pulse heights for …

The Momentum Of The Photon, K F. Ratcliff, David Peak

All Physics Faculty Publications

No abstract provided.

Analysis Of Hyperfine Interactions Of Fe2+ In Fef2, Mnf2 And Znf2, C. R. Abeledo, Richard B. Frankel, A. Misetich

Physics

Analysis of magnetic hyperfine interactions of Fe²⁺ in FeF₂, Fe²⁺:MnF₂ and Fe²⁺:ZnF₂ yields a core polarization hyperfine field H_c = −514 ± 30 kOe and a value of (r⁻³)_eff = 3.9 ± 0.04 au.

Β-Delayed Proton Decay Of 9c, David D. Allred, John E. Esterl, J. C. Hardy, R. G. Sextro, Joseph Cerny

Faculty Publications

The delayed-proton spectrum following the β decay of 9C (t1/2=126.5±1.0 msec) was found to consist primarily of a continuum extending from 13 to 1.5 MeV, the latter being the lowest energy observed. In addition to the previously observed peaks at 9.28 and 12.30 MeV (C.M.), possible peaks between 3 and 7 MeV have been tentatively identified.

Research Project For Undergraduates: Ionic Thermoconductivity In Dielectrics, Richard M. Fuller, Robert Fuller

Robert G. Fuller Publications

Research projects for undergraduates should satisfy several conditions with regards to the physical insight, experimental manipulation, data analyses, and time for the experimental run that are required of the students. These conditions are satisfied by the study of dipole relaxations in dielectric materials using the method of ionic thermocurrents (ITC). ITC can be used to determine the concentration, activation energy, and relaxation time of dipoles in a dielectric. The necessary equipment and some possible research projects are discussed.

Electrical Sensor Of Plane Coordinates, George S. Hurst, James E. Parks

Physics and Astronomy Faculty Patents

An inexpensive electrical sensor of plane coordinates employs juxtaposed sheets of conducting material having electrical equipotential lines extending across each sheet and arranged normal to each other. A probe upon touching each sheet at a selected intersection of the equipotential lines causes separate signals to be applied to one or more conventional information-indicating units.

Cellular Absorbed Dose Spectrometer (Cads) Data Reduction And Analysis., John T. Cervini

Physics & Astronomy ETDs

A detailed description of a space qualified linear energy transfer (LET) spectrometer is presented. The Cellular Absorbed Dose Spectrometer (CADS) is a prototype instrument which was launched on March 17, 1969 into an elliptical orbit. Its purpose was to obtain the first successful LET measurements in space; and, thereby provide additional data to assess the biological hazards of the near earth space environment, especially during periods of in­creased solar activity.

The physical processes that take place in the CADS in­strument are discussed, and a definition of linear energy transfer is given, as well as its relation to dE/dx. The performance …

Molecular Model For Prenucleation Water Clusters, P. L. M. Plummer, Barbara N. Hale

Physics Faculty Research & Creative Works

A molecular model applicable to prenucleation water clusters is described. As an illustration the model is applied to water clusters having clathrate-like structures composed of five-menibered rings. This work was motivated by the apparent inadequacies of the corrected liquid drop model which (in addition to applying bulk properties to small clusters) predicts nucleation rates which may be as much as 10¹⁷ larger than experiment. We present the "energy of formation" at a temperature of 277°K for our molecular model for clusters ranging in size from 5 to 57 molecules. These results agree qualitatively with experiment and, we believe, provide …

Nuclear-Magnetic-Resonance Measurement Of The Conduction-Electron G Factor In Cdte, David C. Look, D. L. Moore

Physics Faculty Publications

The effective g factor g^* of conduction electrons in degenerate CdTe has been determined by using measurements of the Cd¹¹³ nuclear spin-lattice relaxation time T₁ and the Knight shift K. It is shown that the magnitude of g^* is given by the Korringa product T₁TK²=C(g^*)², where C is a known constant and T is the absolute temperature, and that the sign of g^* is given by the sign of K for a spherically symmetric conduction band. The measured value, g^*=-1.1±0.1, is within the range allowed …

Schottky Defects In Alkali Halides, Paul D. Schulze, John R. Hardy

John R. Hardy Papers

The method of lattice statics and the deformation-dipole model have been applied to Schottky defects in ionic crystals in approximations higher than zero order. For an isolated vacancy, all host-lattice-ion potential energy functions for short-ranged repulsive and Coulomb-defect forces were expanded to terms quadratic in the displacements and dipole moments, and the resulting forces were allowed to act on the first and/or second neighbors to the vacancy. The zero-order Coulomb force was allowed to act on the remainder of the host-lattice ions past first and/or second neighbors. The vacancy and Schottky-pair-formation energies in the 12 Na, K, Rb halides have …

Nuclear Quadrupole Coupling Of B-12 In A Single Be Crystal, R. L. Williams Jr., Richard C. Haskell, Leon Madansky

All HMC Faculty Publications and Research

Quadrupole resonance lines of β-unstable 12B have been distinctly resolved in a single crystal of Be, and have behaved properly under field reversal and variation of the angle θ between crystal c axis and external magnetic field.

A Study Of The Kinetics Of Light Induced Modulation Of Absorption In Zinc Selenide, Herbert Seth Berman

Master's Theses

No abstract provided.

Electronic Properties Of Fe2+ In Cubic Kmgf3 From Mössbauer Spectroscopy, Richard B. Frankel, J. Chappert, J. R. Regnard, A. Misetich, C. R. Abeledo

Physics

Iron-doped KMgF₃ single crystals have been studied by Mössbauer spectroscopy of Fe⁵⁷. Single lines due to Fe²⁺ and Fe³⁺ are observed at room temperature. For TK, the Fe²⁺ line splits into a quadrupole doublet with a splitting ΔE_Q=0.44±0.02 mm/sec. Comparison with a random-strain model due to Ham yields a value of 120 cm^-1 for the position of the first excited spin-orbit split level. Magnetic hyperfine structure in external magnetic fields at low temperature is observed and analysis yields a value of -495 ±30 kOe for the corepolarization hyperfine field …

New Thin-Film Tunnel Triode Using Amorphous Semiconductors, Pavel Smejtek, R. F. Shaw, H. Fritzsche, M. Silver, S. Holmberg, S. R. Ovshinsky

Physics Faculty Publications and Presentations

A new thin‐film tunnel triode is discussed which uses a p‐type amorphous film to achieve amplification of injected current from a tunnel cathode. It is not only the basis for a new semiconductor device but also suggests a novel method for measuring electrical properties of semiconductors.

Scattering Spin 1/2 Particles By Nuclei, Pui-Wah Cheng

Masters Theses

No abstract provided.

Digital Video Display System Using Cathode-Ray Tube, George M. Low, Arthur I. Zygielbaum, Warren L. Martin, Alexander Engel

School of Natural Resources: Faculty Publications

A digital video display system (DWDS) is disclosed for display of image, alphanumeric and other data on a cathode-ray tube (CRT) with sequential raster scan and two, four or eight gray shades. The DVDS includes a central processing unit for ac tivating the system, selecting the X (horizontal axis) and Z (in tensity modulation) modes, and designating the starting loca tion of two successive rasters of data from a memory accessed by a data multiplexer subsystem (DMS). At the end of each raster, the DMS interrupts the computer for a new starting lo cation of a raster of data to …