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Calculation Of Potential Functions For Pseudorotation In Five Membered Rings Using Energy Gradients In Extended HüCkel Theory, Thomas Robert Ferguson Apr 1974

Calculation Of Potential Functions For Pseudorotation In Five Membered Rings Using Energy Gradients In Extended HüCkel Theory, Thomas Robert Ferguson

Physics & Astronomy ETDs

The gradient of the energy in extended Hückel theory (EHT) was used in a variable metric algorithm to predict the energy along the pseudorotational path for several five membered ring molecules. The molecules studied were cyclopentane, tetrahydrofuran (THF), cyclopentanol, 4-tetrahydrofuranol, and cis- and trans-3,4-tetrahydrofurandiols. Comparisons of predictions for these molecules to experimental results were made to determine the capabilities of EHT prior to an intended study of sugar rings. A background chapter discusses the recent literature on nucleic acid constituents with emphasis on the geometries of five membered sugar rings. In crystals, these geometries are found to lie mostly in …

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A Method For Measuring The Electrical Conductivity Of A Shocked Liquid, Richard James Hassman Apr 1974

A Method For Measuring The Electrical Conductivity Of A Shocked Liquid, Richard James Hassman

Physics & Astronomy ETDs

Development of a simple technique for the measurement of the gross electrical conductivity of a shock compressed liquid is attempted. A cell containing the sample is constructed from glass cylinders and aluminum foil. The foil is sandwiched between two cylinders of the same diameter to form a two compartment cylinder. The cylinder is mounted on a metal target plate. With both chambers of the system full of liquid, only insignificant reflections can arise from the sample-foil interface. A voltage is placed across the cell between the foil and the target plate, and the change in voltage as the shock front …

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Angular Distribution Of Photoelectrons From Atomic Oxygen, Nitrogen, And Carbon, Steven T. Manson, David J. Kennedy, Anthony F. Starace, Dan Dill Apr 1974

Angular Distribution Of Photoelectrons From Atomic Oxygen, Nitrogen, And Carbon, Steven T. Manson, David J. Kennedy, Anthony F. Starace, Dan Dill

Anthony F. Starace Publications

The angular distributions of photoelectrons from atomic oxygen, nitrogen and carbon are calculated. Both Hartree-Fock and Hartree-Slater (Herman-Skillman) wave functions are used for oxygen, and the agreement is excellent; thus only Hartree-Slater functions are used for carbon and nitrogen. The pitch angle distribution of photoelectrons is discussed and it is shown that previous approximations of energy independent isotropic or sin2 θ distributions are at odds with our results, which vary with energy. This variation with energy is discussed as is the reliability of these calculations.

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Hand Held Probe For Use In Electrical Sensing Of Plane Coordinates, George S. Hurst Apr 1974

Hand Held Probe For Use In Electrical Sensing Of Plane Coordinates, George S. Hurst

Physics and Astronomy Faculty Patents

A probe with a puncturing, electrically conducting needle is constructed to enable the user, whether right or left handed, to position the needle rapidly and accurately at a selected coordinate of a sensor package.

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The Use Of Transactional Analysis With Inquiry Methods In Physics Teaching, Robert Fuller, Ward L. Sims Apr 1974

The Use Of Transactional Analysis With Inquiry Methods In Physics Teaching, Robert Fuller, Ward L. Sims

Robert G. Fuller Publications

We now offer a course that combines an inquiry approach to physics with elementary school science teaching methods and transactional analysis. Our course carries three semester credits in elementary science methods and three semester credits in physics, a total of nine contact hours per week. In previous interim courses the very positive response we have had from our students, i.e., the excitement in discovering some real physics for themselves, and their decision to use the tools of transactional analysis to say "OK" to themselves and physics, leads us to believe that our course can serve as a useful model for …

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Theoretical And Experimental Studies Of The Second-Order Raman Spectra Of Cscl, Csbr, And Csi, B.S. Agrawal, Roger D. Kirby, John R. Hardy Mar 1974

Theoretical And Experimental Studies Of The Second-Order Raman Spectra Of Cscl, Csbr, And Csi, B.S. Agrawal, Roger D. Kirby, John R. Hardy

Roger Kirby Publications

Measurements of the second-order Raman spectra of CsCl, CsBr, and CsI have been made at both 300 and 80 °K. From these the three independent spectral components, A 1g, E g, and T 2g, have been determined for all three crystals at both temperatures. A theoretical interpretation of these data has been carried out using the phenomenological Born-Bradburn model to describe the Raman polarizability tensor and the deformation-dipole model to provide the lattice-dynamical eigendata. We have found it possible to obtain an excellent description of the observed spectra retaining 16 of the first- and second-neighbor polarizability derivatives in the Born-Bradburn …

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Abstract: Phase Transitions In Fecl2·2h2O In External Magnetic Fields: Mössbauer Spectroscopy, L. D. Kandel, M. A. Weber, Richard B. Frankel, C. R. Abeledo Mar 1974

Abstract: Phase Transitions In Fecl2·2h2O In External Magnetic Fields: Mössbauer Spectroscopy, L. D. Kandel, M. A. Weber, Richard B. Frankel, C. R. Abeledo

Physics

Monoclinic FeCl2·2H2O orders antiferromagnetically at TN = 23 K, and the magnetic structure consists of two sublattices of -FeCl2-chains lying along the c-axis. The coupling along the chains is ferromagnetic with weak antiferromagnetic coupling between chains. Application of an external magnetic field along the easy axis (a) induces phase transitions at H1 = 39 kOe and at H2 = 46 kOe.

We report the observation of the three phases using the Mössbauer effect in a single crystal of FeCl2·2H2O cut parallel to the c-axis and placed at …

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An Ok Science Teacher, Robert Fuller Mar 1974

An Ok Science Teacher, Robert Fuller

Robert G. Fuller Publications

Many elementary school teachers feel insecure and unsure in their teaching of science, i.e., they have NOT OK feelings about themselves and science. These feelings are based on the teachers' previous science experiences and on their interactions with other persons in science courses. The improvement of elementary school science programs depends upon the teacher's ability to deal effectively with his feelings about science. A complete science education program for an elementary teacher includes three components: (1) science content, (2) science methods that take into consideration the intellectual development of children, and (3) a practical psychology for developing positive human attitudes …

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Phonon-Induced Second-Order Raman Scattering In Lif, T.P. Sharma, Roger D. Kirby, Sitaram Jaswal Feb 1974

Phonon-Induced Second-Order Raman Scattering In Lif, T.P. Sharma, Roger D. Kirby, Sitaram Jaswal

Roger Kirby Publications

We have studied experimentally and theoretically the second-order Raman spectra of LiF. Theoretical calculations based on Born and Bradburn's approach explain the observed spectra fairly well when all the eight-nearest-neighbor, only two of the fifteen-next-nearest-neighbor negative-negative, and none of the fifteen next-nearest-neighbor positive-positive polarizability coefficients are used as adjustable parameters.

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Evidence For The Ωππ Decay Modes Of The A₂ And Ω(1675), J. Diaz, F. A. Dibianca, William J. Fickinger, A. Malko, D. K. Robinson, C. R. Sullivan Feb 1974

Evidence For The Ωππ Decay Modes Of The A₂ And Ω(1675), J. Diaz, F. A. Dibianca, William J. Fickinger, A. Malko, D. K. Robinson, C. R. Sullivan

Faculty Scholarship

We present evidence for the decay A20→ωπ+π0 with a branching ratio Γ(A2→ωππ)/Γ(A2→ρπ)=0.28±0.09 and for the decay ω(1675)→ωπ+π- with a branching ratio Γ(ω(1975)→ωπ+π-)/Γ(ω(1675)→ρπ)=0.47±0.18. Evidence is given for an intermediate B(1235)π state in the ω(1675) decay.

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Pb And Bi L-Subshell Ionization Cross-Section Ratios Versus Proton Bombarding Energy From 0.5 To 4 Mev, Don H. Madison, A. B. Baskin, C. E. Busch, Stephen M. Shafroth Feb 1974

Pb And Bi L-Subshell Ionization Cross-Section Ratios Versus Proton Bombarding Energy From 0.5 To 4 Mev, Don H. Madison, A. B. Baskin, C. E. Busch, Stephen M. Shafroth

Physics Faculty Research & Creative Works

Experimental ratios of L-subshell cross sections are given for ionization of lead and bismuth by 0.5-4-MeV-proton bombardment. The ratio of the LII to LI cross sections exhibits a maximum near 1.75 MeV. Individual subshell cross sections are obtained from the experimental ratios and previous total-cross-section data. These subshell ratios and cross sections are compared with the theoretical predictions of the plane-wave Born approximation using nonrelativistic hydrogenic wave functions, of the binary-encounter approximation scaled from Mg K-shell cross sections, and of the binary-encounter approximation scaled from cross sections obtained using L-shell velocity distributions. It was found that both approximations …

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Diffusion-Controlled Intrachain Reactions Of Polymers. I Theory, Gerald Wilemski, Marshall Fixman Feb 1974

Diffusion-Controlled Intrachain Reactions Of Polymers. I Theory, Gerald Wilemski, Marshall Fixman

Physics Faculty Research & Creative Works

A theory of diffusion-controlled intramolecularly catalyzed reactions of polymer chains in dilute solution is formulated. A closure approximation yields a soluble integral equation for (essentially) the transient rate of the reaction. The time dependent solution consists of a sum of simple exponential terms whose coefficients and decay constants can be readily calculated. The theory is also applied to luminescence quenching and ring-chain interconversion.

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Diffusion-Controlled Intrachain Reactions Of Polymers. Ii Results For A Pair Of Terminal Reactive Groups, Gerald Wilemski, Marshall Fixman Feb 1974

Diffusion-Controlled Intrachain Reactions Of Polymers. Ii Results For A Pair Of Terminal Reactive Groups, Gerald Wilemski, Marshall Fixman

Physics Faculty Research & Creative Works

The formulas and results of the preceding paper are used to calculate the rate of reaction between reactive groups attached to the ends of a polymer chain. Extensive numerical calculations have been made for both transient rate processes and steady state luminescence quenching. The results are restricted to chains in dilute solution, in either the free draining or nondraining limits and with no excluded volume forces present. A discussion of the qualitative effects of excluded volume forces on the results is included. The results suggest that experimental studies of these processes may be feasible.

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Eikonal Approximation Applied To Atom-Atom Excitation At Intermediate Energies: Excitation Of H By H, Richard H. Shields, Jerry Peacher Feb 1974

Eikonal Approximation Applied To Atom-Atom Excitation At Intermediate Energies: Excitation Of H By H, Richard H. Shields, Jerry Peacher

Physics Faculty Research & Creative Works

The eikonal distorted-wave Born approximation (DWBA) developed recently by Chen, Joachain, and Watson is applied to atom-atom excitation in the intermediate energy range. In this paper the excitation of a hydrogen atom to the 2s, 2p±, or 2p0 state by hydrogen impact is considered. Differential cross sections are presented. Total cross sections are presented and compared to previous calculations. It is shown that the eikonal DWBA results for the total cross section approach the two-state distortion-approximation results in the limit of high energy and very-small-angle scattering.

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Mössbauer Spectroscopy Of Magnetic Phases In Fecl2 · 2h2O, L. Kandel, M. A. Weber, Richard B. Frankel, C. R. Abeledo Jan 1974

Mössbauer Spectroscopy Of Magnetic Phases In Fecl2 · 2h2O, L. Kandel, M. A. Weber, Richard B. Frankel, C. R. Abeledo

Physics

Mössbauer spectroscopy of the three magnetic phases of single crystal FeCl2 · 2H2 in external magnetic fields at 4.2 K is reported.

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Effect Of Virtual 4d-Shell Excitations On Rare Earth Spectra, Anthony F. Starace Jan 1974

Effect Of Virtual 4d-Shell Excitations On Rare Earth Spectra, Anthony F. Starace

Anthony F. Starace Publications

Ab initio energies for electric dipole transitions 4d10 (1S0) → 4d94f J = 1 in triply-ionized lanthanum have been calculated by constructing an effective interaction, acting within the configuration 4d94f, that incorporates effects of virtual 4d-shell excitations to all orders of perturbation. Virtual 4d-shell excitations, included within the random phase approximation, and virtual excitations to singly-excited configurations 4d9εf are found to reduce the ordinary electrostatic interaction by 38% for the 1P1 term of 4d94f, by 6% for the 3D1 term, and by 3% …

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Incoherent-Scatter Radar Observations Of Westward Electric Fields, 2, C L. Rino, Vincent B. Wickwar, P M. Banks, E Rieger, S Akasofu Jan 1974

Incoherent-Scatter Radar Observations Of Westward Electric Fields, 2, C L. Rino, Vincent B. Wickwar, P M. Banks, E Rieger, S Akasofu

All Physics Faculty Publications

In this paper we describe the results of a series of geomagnetic meridian plane radar incoherent scatter plasma transport measurements. From such data the eastward (zonal) component of the electric field can be deduced. The results show that the electric field has an eastward component whenever the discrete auroras are northward of the region of the measurement. The zonal field component turns westward as the discrete auroras move equatorward of the region of the measurement. Thus there is an eastward electric field boundary near the equatorward limit of the discrete aurora, which is the poleward boundary of the diffuse aurora …

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Physical Meaning Of The Field H, H. E. Mccloud Jan 1974

Physical Meaning Of The Field H, H. E. Mccloud

Journal of the Arkansas Academy of Science

Through the introduction of the concept of magnetic charge the physical meaning of the magnetic field H is established within the rationalized MKS system of units

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Incoherent Scatter Radar Observations Of Westward Electric Fields And Plasma Densities In The Auroral Ionosphere, 1, M P. Banks, C L. Rino, Vincent B. Wickwar Jan 1974

Incoherent Scatter Radar Observations Of Westward Electric Fields And Plasma Densities In The Auroral Ionosphere, 1, M P. Banks, C L. Rino, Vincent B. Wickwar

All Physics Faculty Publications

This paper reports the results of incoherent scatter radar observations of high-altitude ion drifts and other plasma parameters made February 24, 1972, at Chatanika, Alaska (L = 5.7), during a period of magnetic disturbance. For this experiment, conducted between 0909 to 1303 UT (2309 to 0303 AST), the radar line of sight was held fixed in the magnetic meridian plane so that the observed north-south ion drifts could be interpreted in terms of a westward electric field that ranged in magnitude from −10 to +35 mV m−1. The results confirm many effects found previously through other experimental …

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Combined Airglow And Incoherent Scatter Observations As A Technique For Studying Neutral Atmospheric Variations, L L. Cogger, Vincent B. Wickwar, Herbert C. Carlson Jan 1974

Combined Airglow And Incoherent Scatter Observations As A Technique For Studying Neutral Atmospheric Variations, L L. Cogger, Vincent B. Wickwar, Herbert C. Carlson

All Physics Faculty Publications

Night airglow 6300 Å intensities and electron density altitude profiles observed at Arecibo have been combined with dissociative recombination theory to obtain information about the nighttime variation of F-region N2 and O2 densities. The application of this technique is illustrated using data from two nights in March 1971. The gross nighttime variation shows reasonable similarity to the Jacchia [1970] model, and also follows the time variation of the measured exospheric temperature. However, on both nights there is evidence of a postmidnight enhancement of the O2/N2 density ratio associated with a rapid decrease in the …

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Study Of Stopping Sites Of B12 Nuclei Implanted In Hexagonal Single-Crystals, Francis David Correll, Richard C. Haskell, Leon Madansky Jan 1974

Study Of Stopping Sites Of B12 Nuclei Implanted In Hexagonal Single-Crystals, Francis David Correll, Richard C. Haskell, Leon Madansky

All HMC Faculty Publications and Research

A series of experiments to study the stopping sites of 12B nuclei implanted in single crystals of Be and Mg will be discussed. Previous measurements of the quadrupole couplings of 12B in these metals indicated that two different stopping sites existed, one of which produced a negligible quadrupole coupling.

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High-Temperature Annealing In Electron-Irradiated Cds, David C. Look Jan 1974

High-Temperature Annealing In Electron-Irradiated Cds, David C. Look

Physics Faculty Publications

The room‐temperature irradiation of as‐grown n‐type CdS by 1‐MeV electrons results in an increase in carrier concentration. The damage anneals in the temperature range 250–300°C, and a study of the annealing kinetics reveals an activation energy of about 1.3 eV which is attributed to sulfur‐vacancy motion.

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Structural Strain In Small Prenucleation Water Clusters, Donald E. Hagen Jan 1974

Structural Strain In Small Prenucleation Water Clusters, Donald E. Hagen

Physics Faculty Research & Creative Works

A method is developed for incorporating strain energy into a microphysical treatment of small prenucleation water clusters. The molecules are arranged in a clathrate-cage structure, and this structure is allowed to relax to minimize the strain energy resulting from hydrogen bond stretching and bending. The method is applied to various cluster sizes up to 130 molecules and the results are compared with the classical liquid drop model. The effect of anharmonic terms in the interaction is included.

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Fresnel Drag In Uniformly Moving Media, William F. Parks, J. T. Dowell Jan 1974

Fresnel Drag In Uniformly Moving Media, William F. Parks, J. T. Dowell

Physics Faculty Research & Creative Works

A general first-order formula is derived for the Fresnel-drag effect in a uniformly moving medium with a plane surface. The two classical equations due to Lorentz and Laub are shown to be special cases corresponding to different experimental arrangements. The recent experiment of Bilger and Zavodny on Fresnel drag in a ring laser is discussed. © 1974 The American Physical Society.

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Measurements Of The Average Electric Dipole Polarizabilities Of The Alkali Dimers, Robert W. Molof, Thomas M. Miller, Henry L. Schwartz, Benjamin Bederson, John T. Park Jan 1974

Measurements Of The Average Electric Dipole Polarizabilities Of The Alkali Dimers, Robert W. Molof, Thomas M. Miller, Henry L. Schwartz, Benjamin Bederson, John T. Park

Physics Faculty Research & Creative Works

The average electric dipole polarizabilities of the homonuclear alkali dimers have been measured in an electric deflection experiment. The molecular results are normalized to the corresponding atomic polarizabilities by comparing deflections of atomic and molecular alkali beams passing through an inhomogenous electrostatic field. The average polarizabilities in units of 10-24 cm3 are: Li2(990°K), 34±3; Na2(736°K), 30±3; K2(569°K), 61±5; Rb2(534°K), 68±7; Cs2(515°K), 91±7. Copyright © 1974 American Institute of Physics.

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On The Lambda Transition In Solid Orthohydrogen, Harry A. Brown Jan 1974

On The Lambda Transition In Solid Orthohydrogen, Harry A. Brown

Physics Faculty Research & Creative Works

No abstract provided.

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Optical Pumping In A Flowing Helium Afterglow With Additive Metal Impurity Atoms, Laird D. Schearer Jan 1974

Optical Pumping In A Flowing Helium Afterglow With Additive Metal Impurity Atoms, Laird D. Schearer

Physics Faculty Research & Creative Works

It is demonstrated that in a Penning collision of optically oriented metastable helium atoms with an impurity metal atom such as barium, both the longitudinal and transverse components of spin angular momentum are conserved. This results in a polarization of the ion which may be detected by optical emission in the case of excited ion levels or absorption for the ground states. A series of experiments is described which demonstrates the spin dependence of the Penning-collision process. The magnetic resonance of excited-state ions may be observed directly; from the resonance-linewidth radiative lifetimes may be measured. © 1974 The American Physical …

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Evaluation Of Model For The Contributin Of Phonon-Induced Tunneling To Donor Esr Spectral Narrowing In Germanium, David L. Meier, William F. Parks, Edward Boyd Hale Jan 1974

Evaluation Of Model For The Contributin Of Phonon-Induced Tunneling To Donor Esr Spectral Narrowing In Germanium, David L. Meier, William F. Parks, Edward Boyd Hale

Physics Faculty Research & Creative Works

The model commonly assumed to explain the narrowing of the ESR spectra of donor impurities in germanium is examined in detail. This model combines the Anderson line-narrowing theory with the Miller and Abrahams theory for the phonon-induced tunneling (hopping) of an electron between impurities. The predictions of this model are found to be in drastic disagreement with experimental results now available. It is shown that the narrowed linewidth should depend strongly on donor concentration, acceptor concentration, and temperature. Future spin-resonance experiments in highly compensated samples may show the effects of hopping, but no evidence now exists which indicates that hopping …

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Statistical Time-Dependent Model For The Interstellar Gas, H. Gerola, Menas Kafatos, R. Mccray Jan 1974

Statistical Time-Dependent Model For The Interstellar Gas, H. Gerola, Menas Kafatos, R. Mccray

Mathematics, Physics, and Computer Science Faculty Articles and Research

We present models for temperature and ionization structure of low, uniform-density (n ~ 0.3 cm^-3) interstellar gas in a galactic disk which is exposed to soft X-rays from supernova outbursts occurring randomly in space and time. The structure was calculated by computing the time record of temperature and ionization at a given point by Monte Carlo simulation. The calculation yields probability distribution functions for ionized fraction x, temperature T, and their various observable moments. These time-dependent models predict a bimodal temperature distribution of the gas with structure in x, T that agrees with various observations. Cold regions in the low-density …

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Phase Transitions In Antiferromagnets In External Magnetic Fields: Mossbauer Spectroscopy, Richard B. Frankel Jan 1974

Phase Transitions In Antiferromagnets In External Magnetic Fields: Mossbauer Spectroscopy, Richard B. Frankel

Physics

No abstract provided.

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