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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.

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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 …

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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

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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

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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.

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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 …

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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.

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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.

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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 …

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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.

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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 …

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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 …

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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.

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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.

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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 …

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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 …

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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 …

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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) …

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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.

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A Survey Of The Methods For Producing Extremely Low Temperatures, Patricia M. Boise

Departmental Honors & Graduate Capstone Projects

A Survey of the Methods for Producing Extremely Low Temperatures

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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 …

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Geophysical Institute Annual Report 1968-69, University Of Alaska Fairbanks. Geophysical Institute

GI Reports

The 1968–69 Geophysical Institute Annual Report presents an overview of the year’s scientific research achievements across the Institute’s disciplines, alongside operational summaries covering finances, administrative changes, and other key activities.

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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 …

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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 …

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A Study Of The Energy Loss Spectra Induced By Impact Of 23-125 Kev Protons On Helium Atoms, Franklin Dean Schowengerdt

Doctoral Dissertations

"Results of a study of the inelastic energy loss spectra induced by the impact of protons on gaseous helium at energies of 25 to 125 keV are reported. The spectra were obtained by sending an accelerated beam of protons through a chamber containing the helium target gas, mass-analyzing the forward-scattered beam, then decelerating the beam to a low, well-defined energy for energy analysis and detection. The accelerating potential was varied to produce the spectra. An energy resolution of 2 eV was obtained. Apparent differential cross sections and absolute total cross sections were obtained from the spectra. Total cross sections for …

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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 …

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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 …

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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.

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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 …

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

Physics Faculty Publications

No abstract provided.

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Full-Text Articles in Entire DC Network

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

Robert Katz Publications

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

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

Gordon Gallup Publications

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

Gordon Gallup Publications

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

Physics

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

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

Physics

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

All Physics Faculty Publications

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

Robert G. Fuller Publications

Consistency And Cluster Size In The Effective Field Theories Of Ferromagnetism, J. G. Chervenak, Harry A. Brown

Physics Faculty Research & Creative Works

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

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

Mixed Magnetic Systems: A Model With Application To (1-X)Cdcr2s4 · Xcdcr2se4, Harry A. Brown

Physics Faculty Research & Creative Works

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

Masters Theses

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

Doctoral Dissertations

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

Doctoral Dissertations

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

Doctoral Dissertations

An Experimental Comparison Of Various Nuclei Counters, Joel William Mansell

Masters Theses

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

Masters Theses

A Survey Of The Methods For Producing Extremely Low Temperatures, Patricia M. Boise

Departmental Honors & Graduate Capstone Projects

A Low Frequency Phase Shift Method, Ronnie Carroll Mcmillan

Masters Theses

Geophysical Institute Annual Report 1968-69, University Of Alaska Fairbanks. Geophysical Institute

GI Reports

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

Doctoral Dissertations

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

Doctoral Dissertations

A Study Of The Energy Loss Spectra Induced By Impact Of 23-125 Kev Protons On Helium Atoms, Franklin Dean Schowengerdt

Doctoral Dissertations

Longitudinal Optical Phonon-Plasmon Coupling In Ionic Semiconductors, Thomas Joseph Mcmahon

Doctoral Dissertations

Vapor Phase Clustering Model For Water, Richard W. Bolander

Doctoral Dissertations

Detection Of Vibrationally Excited N2 By Superelastic Electron Impact, Paul Burrow, Paul Davidovits

Paul Burrow Publications

Ionic Transport In Potassium Chloride, Robert Fuller, Charles L. Marquardt, Michael H. Reilly, John C. Wells Jr.

Robert G. Fuller Publications

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

Physics Faculty Publications