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The Breakdown Of Hund's Rule In Systems Of Fourfold Symmetry, Gordon A. Gallup Apr 1987

The Breakdown Of Hund's Rule In Systems Of Fourfold Symmetry, Gordon A. Gallup

Gordon Gallup Publications

The lowest energies of molecular systems with fourfold symmetry can violate Hund's multiplicity rule. We derive relationships between two electron integrals that in favorable cases allow one to predict when this will happen. These relationships result in a fairly simple inequality as a criterion. The systematics of the phenomenon are illustrated with a series of calculations on model systems consisting of hydrogen atoms. These are rings of three, four, five, six, seven, and eight members as well as octahedral and square planar arrangements. These show how the results and simple ideas of molecular orbital theory can be qualitatively modified when …

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Separated Resonances In Simultaneous Capture And Excitation Of S¹⁵⁺ In H₂ Observed By K-X-Ray K-X-Ray Coincidences, Michael Schulz, Edson L B Justiniano, Reinhold S. Schuch, Paul H. Mokler, S. Reusch Apr 1987

Separated Resonances In Simultaneous Capture And Excitation Of S¹⁵⁺ In H₂ Observed By K-X-Ray K-X-Ray Coincidences, Michael Schulz, Edson L B Justiniano, Reinhold S. Schuch, Paul H. Mokler, S. Reusch

Physics Faculty Research & Creative Works

We have measured cross sections for the correlated emission of two K x rays following the collision of hydrogenlike sulfur ions with H2 in the energy range between 70 and 160 MeV. The observation of the two correlated x rays is interpreted as a resonant capture of a target electron accompanied by simultaneous excitation of the projectile in the collision (RTE). By our distinguishing between Kα and Kβ lines, contributions from KLL and KLn (n≥M) resonances could be determined independently.

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Semiclassical Analysis Of A Detuned Ring Laser With A Saturable Absorber: New Results For The Steady States, D. E. Chyba, N. B. Abraham, Alfonso M. Albano Apr 1987

Semiclassical Analysis Of A Detuned Ring Laser With A Saturable Absorber: New Results For The Steady States, D. E. Chyba, N. B. Abraham, Alfonso M. Albano

Physics Faculty Research and Scholarship

This paper presents new results for the steady states of a detuned ring laser with a saturable absorber. We employ a semiclassical model which assumes homogeneously broadened two-level atoms. We proceed by solving the Maxwell-Bloch equations for the longitudinal dependence of the steady states of this system, and then simplify our solution by use of the uniform-field approximation. We present uniform-field results for squared electric field versus operating frequency, and for each of these versus cavity tuning and laser excitation. Various cavity linewidths and both resonant and nonresonant amplifier and absorber line-center frequencies are considered. The most notable finding is …

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Search For An Instability On A Quenched-Liquid Interface, Steven N. Rauseo, Nalini Easwar, James V. Maher Apr 1987

Search For An Instability On A Quenched-Liquid Interface, Steven N. Rauseo, Nalini Easwar, James V. Maher

Physics: Faculty Publications

We searched for signs of an instability on the interface between the two phases of a binary-liquid mixture, isobutyric acid and water, after the mixture was quenched further into the two-phase region. Such an instability would be the liquid-liquid analog of the Mullins-Sekerka instability seen in quenched alloys. Never is any dramatic growth observed, but under conditions of small dimensionless quench depth (theta<1.5×10−3), the intensity of light scattered from the interface grows for small values of the momentum transfer k.

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Testing Of Beam Line For Charge Exchange Measurements, Mohd. Noor Ali Apr 1987

Testing Of Beam Line For Charge Exchange Measurements, Mohd. Noor Ali

Masters Theses

The atomic physics beam line in the Western Michigan University accelerator laboratory was tested for the first time for making atomic charge-exchange experiments. Cross sections obtained for single electron capture and loss for 25 MeV oxygen ions incident on a helium gas target are in reasonable agreement with previous measurements. These results indicate that the system is operating properly. An attempt to observe a nuclear resonance effect on electron capture and/or loss was not successful. However, it was determined that additional collimation is necessary for such measurements.

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A Study Of The Direct Capture Process Of Protons By 27Al, Rozana Hussain Apr 1987

A Study Of The Direct Capture Process Of Protons By 27Al, Rozana Hussain

Masters Theses

An experimental investigation of the 27Al(p,γ)28Si reaction was made for protons in the energy range 550- to 1785-keV and at angles of 0, 20, 55, 90 and 118 degrees. Four angular distributions at Ep = 845-, 1055-, 1135-, and 1618-keV were selected for detailed study. These angular distributions were fit with theoretical calculations employing a directcapture model. These fits permitted the extraction of spectroscopic factors for the population of the first excited-state in 28Si by proton transfer.

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Science And Society Test X: Energy Conservation, David W. Hafemeister Apr 1987

Science And Society Test X: Energy Conservation, David W. Hafemeister

Physics

United States energy consumption has remained essentially constant at about 80 exajoules/year (75 quads/year) since the oil embargo of 1973–1974, while the GNP in constant dollars has increased by about 30%. This article will discuss the physics behind some of these improvements in end-use efficiency in such areas as: (i) buildings (scaling laws, "free-heat,'' superinsulated houses, thermal storage in large buildings, off-peak cooling), (ii) solar energy (passive, photovoltaics), (iii) utility load management ("smart meters,'' capital recovery fees, voltage control), (iv) appliances (life-cycle costs, refrigerators), and (v) lighting (isotopic enhancement).

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Excitation Of The Isobaric Analog State Of ¹⁶⁵Ho By Pion Single-Charge Exchange, William J. Fickinger Apr 1987

Excitation Of The Isobaric Analog State Of ¹⁶⁵Ho By Pion Single-Charge Exchange, William J. Fickinger

Faculty Scholarship

Forward-angle differential cross sections for the 165Ho(π+,π0)165Er(IAS) reaction have been measured at Tπ=98.0, 163.2, and 228.3 MeV in the angular range & ≲14°. The shapes of the angular distributions at 98.0 and 163.2 MeV are compared to predictions arising from the strong absorption model of pion single-charge exchange scattering. Extrapolated 0° cross sections are compared with trends previously established with mostly spherical and near-spherical nuclei. The measurement demonstrates the possibility of using the (π+,π0) reaction for studying neutron density deformations in oriented 165Ho.

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On A Moving Boundary Problem Of Transitional Ballistics, Jen-Ing G. Hwang Apr 1987

On A Moving Boundary Problem Of Transitional Ballistics, Jen-Ing G. Hwang

Mathematics & Statistics Theses & Dissertations

A major problem which arises in computer simulation of the firing of a gun weapon is the development of numerical schemes which effectively account for the physics of projectile motion. The chief difficulty is that away from the projectile the calculation is ordinarily accomplished on a fixed numerical grid, whereas due to projectile movement some cells of the grid near the projectile undergo volume changes as the calculation proceeds. A local finite volume scheme is developed which accounts for the expansion or compression of cells fore-and-aft of the projectile. Through the process of numerical experiment, the effectiveness of the scheme …

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A Numerical Study Of Three-Dimensional Vortex Breakdown, Robert Edward Spall Apr 1987

A Numerical Study Of Three-Dimensional Vortex Breakdown, Robert Edward Spall

Mechanical & Aerospace Engineering Theses & Dissertations

A numerical simulation of vortex breakdown using the time-dependent Navier-Stokes equations was performed. Unlike previous studies, the numerical algorithm, formulated in terms of the velocity and vorticity, was not restricted to axisymmetric flows. Prototype vortices were parameterized in terms of their Reynolds number and Rossby number. Two cases were studied extensively. In one case, a vortex was imbedded in a uniform free stream. In the other case, the axial velocity of the free stream was decelerated in the streamwise direction. For both cases breakdown occurred when the Rossby number was below a critical value. Vortex lines, particle traces and velocity …

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Studies Of Radiation Effects In Three High Polymers, Heidi Rene-Mitchell Ries Apr 1987

Studies Of Radiation Effects In Three High Polymers, Heidi Rene-Mitchell Ries

Physics Theses & Dissertations

Three high polymers, Mylar®, Ultem®, and Kapton®, were irradiated to total doses of 1, 5, and 9.5 gigarad using 1-MeV electrons. The glass transition temperatures (Tg) of the materials before and after irradiation were measured using an AC electrical dissipation factor technique. From the Tg data, it was found that the electron radiation at these total doses results in net chain scissioning in Mylar and net crosslinking in Ultem, while self-mending is predominant in Kapton. The dielectric constant was measured before and after irradiation, but no significant changes due to irradiation were observed. Electron paramagnetic resonance (EPR) …

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Inactivation Of Dry Enzymes And Viruses By Energetic Heavy Ions, M. P. R. Waligorski, Kim Sun Loh, Robert Katz Mar 1987

Inactivation Of Dry Enzymes And Viruses By Energetic Heavy Ions, M. P. R. Waligorski, Kim Sun Loh, Robert Katz

Robert Katz Publications

A newly developed corrected formula for the radial distribution of dose (RDD) has been used to calculate cross sections for the inactivation of dry enzymes and viruses by heavy ions ranging from 42He to 4018 Ar of energies ca. 10 MeV/a.m.u., spanning a range of LET of ca. 5–2,000 Me V cm2 g–1. In comparison with earlier “point-target” calculations of Butts and Katz where a linear range-energy relationship for electrons (δ-rays) was used, and with “extended-target” calculations of Zhang, Dunn, and Katz, where a power range-energy law and an “uncorrected” RDD formula …

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Two-Dimensional Polymer Melts, Rolfe G. Petschek Mar 1987

Two-Dimensional Polymer Melts, Rolfe G. Petschek

Faculty Scholarship

We discuss the asymptotic highmolecular-weight behavior of flexible, weakly repulsive polymer chains in melts, both through an analogy to an O(n) model of magnets and directly. We show that such polymers are slightly expanded in two dimensions so that in the limit of very high molecular weight, polymers interpenetrate strongly and the fraction of the monomers belonging to a polymer within the radius of gyration of that polymer tends to zero logarithmically. The molecular-weight or length-scale dependence of the radius of gyration, osmotic pressure, and end-end scattering function is given. The range of parameters for which this behavior is expected …

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Binding Of Fe2+ By Mammalian Ferritin, Richard B. Frankel, G. C. Papaefthymiou, G. D. Watt Mar 1987

Binding Of Fe2+ By Mammalian Ferritin, Richard B. Frankel, G. C. Papaefthymiou, G. D. Watt

Physics

An average of 140 Fe2+ ions bind to mammalian ferritin that has an average core content of 1876 Fe3+ ions per molecule. The Fe2+ ions enter the protein interior and exchange electrons with the core Fe3+ ions. A non-homogeneous model for the iron-containing core of ferritin is proposed.

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Fresnel Diffraction Effects In Misfocused Vision, James A. Lock Mar 1987

Fresnel Diffraction Effects In Misfocused Vision, James A. Lock

Physics Faculty Publications

If a narrow line stimulus on an opposite contrast background is observed with appropriately misfocused vision, the stimulus appears as a number of alternating bright and dark fringes. A numerical calculation of this effect was performed. As a result it was found that the banding phenomenon is a Fresnel diffraction effect depending on the details of both the narrow line stimulus and the eye pupil.

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Multicritical Susceptibility Sum Rules, Miron Kaufman, Michael Ma Mar 1987

Multicritical Susceptibility Sum Rules, Miron Kaufman, Michael Ma

Physics Faculty Publications

Asymptotically close to the Nth-order multicritical point of an N-phase system, there are N-1 sum rules involving the mean-field susceptibilities measured in each of the coexisting phases. These sum rules provide the experimentalist a convenient and stringent test of the theory. In particular, they facilitate the detection of nonclassical effects, especially valuable for N>3 where the fluctuation effect is dominated by the classical contribution for three-dimensional systems.

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Comparison Of Low-Energy Seismic Sources In Till, Paul J. Wolfe, B. H. Richard, Dale V. Dailey, James R. Plomer Mar 1987

Comparison Of Low-Energy Seismic Sources In Till, Paul J. Wolfe, B. H. Richard, Dale V. Dailey, James R. Plomer

Physics Faculty Publications

No abstract provided.

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Fourier Transform Of The Product Of N One-Center Hydrogenic Orbitals, Jack C. Straton Mar 1987

Fourier Transform Of The Product Of N One-Center Hydrogenic Orbitals, Jack C. Straton

Physics Faculty Publications and Presentations

Integrating the radial part of the Fourier transform of the product of N hydrogenic orbitals results in an associated Legendre function that can be reduced to a finite series of elementary functions. This transform is found to depend on a polynomial in the wave vector k divided by a binomial in k2 raised to a power that is the sum of principle quantum numbers. This form facilitates the analytical reduction of integrals arising from orthogonalization corrections in atomic processes. Transforms for the product of orbital pairs (1s,1s) through (1s,3d) are given …

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Transport Anisotropy And Percolation In The Two-Dimensional Random-Hopping Model, Kalyan P. Kundu, Paul Ernest Parris, Philip W. Phillips Mar 1987

Transport Anisotropy And Percolation In The Two-Dimensional Random-Hopping Model, Kalyan P. Kundu, Paul Ernest Parris, Philip W. Phillips

Physics Faculty Research & Creative Works

We consider hopping transport on an anisotropic two-dimensional square lattice. The displacements parallel to one axis are governed by uniform, nearest-neighbor hopping rates c, while the displacements parallel to the other axis are governed by static but spatially fluctuating rates wn. Adapting a new class of generating functions recently introduced for the random-trapping problem, we are able to obtain expressions for the mean-square displacement in the fluctuating direction through an exact decoupling of the effects due to displacements in the uniform direction. The resulting expressions for the low-frequency diffusion coefficient D(ε) are exact in the limits c →0 …

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Recoil Ions From Close 20-Kev H+ Collisions With O2, Co, Co2, And Ne, Akio Itoh, M. Eugene Rudd Feb 1987

Recoil Ions From Close 20-Kev H+ Collisions With O2, Co, Co2, And Ne, Akio Itoh, M. Eugene Rudd

M. Eugene Rudd Publications

Recoil ions ejected at 70° from 20-keV proton collisions with O2, CO, CO2, and Ne were analyzed by an electrostatic analyzer. For the molecular targets, only singly ionized ions of oxygen or carbon were detected while in the spectrum of neon ions, Ne+ and Ne2+ were both observed. The absence of O2+, CO+, and CO2+ is due to the fact that the recoil ions detected in this experiment result only from very close collisions with one of the atoms in the molecule resulting in dissociation. A possible …

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Composition Range Of Binary Amorphous Alloys, Sy_Hwang Liou, C.L. Chien Feb 1987

Composition Range Of Binary Amorphous Alloys, Sy_Hwang Liou, C.L. Chien

Sy-Hwang Liou Publications

We have studied a number of binary metal-metal and metalloid alloy systems made by a single vapor-quench method under very consistent conditions. In each case, amorphous alloys are found in one continuous composition range (xmin≤x≤xmax) regardless of the number of eutectic points in the equilibrium phase diagrams. It is found that the atomic size difference is the single most important factor in the quantitative determination of the composition range.

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Antireflection Of An Absorbing Substrate By An Absorbing Thin Film At Normal Incidence, R. M.A. Azzam, E. Bu-Habib, J. Casset, G. Chassaing, P. Gravier Feb 1987

Antireflection Of An Absorbing Substrate By An Absorbing Thin Film At Normal Incidence, R. M.A. Azzam, E. Bu-Habib, J. Casset, G. Chassaing, P. Gravier

Electrical Engineering Faculty Publications

An absorbing substrate of complex refractive index n2 - jk2 at wavelength λ can be coated by an absorbing thin film of complex refractive index n1 - jk1 and thickness d to achieve zero reflection at normal incidence. For given n2,k2 multiple solutions (n1,k1,d/λ) are found that correspond to infinitely many distinct antireflection layers. This is demonstrated for a Si substrate at two wavelengths (6328 and 4420 Å). The response of these absorbing antireflection layers to changes of the angle of incidence from 0 …

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Equivalence Of Donor And Acceptor Fits Of Temperature-Dependent Carrier-Concentration Data, David C. Look, J. R. Sizelove Feb 1987

Equivalence Of Donor And Acceptor Fits Of Temperature-Dependent Carrier-Concentration Data, David C. Look, J. R. Sizelove

Physics Faculty Publications

It is shown that the usual charge-balance analysis of temperature-dependent carrier-concentration data cannot distinguish between the donor and acceptor behavior of a center which is emitting carriers to a particular band, even though the statistics are different in the two cases. Other data, such as mobility or analytical results are needed to make the distinction.

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Demountable Piezoelectric Transducer Holder For Use At Low Temperatures, Matthew J. Moelter, M. B. Manning, C. Ebaum Feb 1987

Demountable Piezoelectric Transducer Holder For Use At Low Temperatures, Matthew J. Moelter, M. B. Manning, C. Ebaum

Physics

We present a design for a piezoelectric transducer holder for use at low temperatures, which is easily constructed and assembled. Improved acoustic signals with "ringing" eliminated were reliably obtained. The standard problems of demountability, electrical integrity, and leak tightness in the presence of liquid helium at moderate pressures were resolved.

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Variational Treatment Of A Harmonic Oscillator Coupled To A Dissipative Heat Bath, Paul Ernest Parris, Robert J. Silbey Feb 1987

Variational Treatment Of A Harmonic Oscillator Coupled To A Dissipative Heat Bath, Paul Ernest Parris, Robert J. Silbey

Physics Faculty Research & Creative Works

We consider the problem of a single quantum oscillator coupled linearly to a heat bath of independent harmonic modes. An exact solution is presented for the system-oscillator observables of interest. The exact results are then used to evaluate the utility of a variational approach to the problem that has proven useful recently in elucidating the dynamics of dissipatively coupled systems. We find that the variational approach does provide a good description for most, but not all, observables of interest. Both the exact and the variational treatment demonstrate the important role played by the low-frequency bath modes in determining qualitative features …

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Optically Phased Laser Transmitter, Janet S. Fender, Salvatore J. Cusumano, Robert R. Butts, Christopher R. Dehainaut Jan 1987

Optically Phased Laser Transmitter, Janet S. Fender, Salvatore J. Cusumano, Robert R. Butts, Christopher R. Dehainaut

AFIT Patents

An apparatus and technique are described for phasing the outputs of a multiplier telescope array used as a laser transmitter. The technique uses samples of the transmitted beams to control optical path lengths through the separate telescopes so that the beams add coherently at the receiver. The phasing concept is applicable both to systems which provide inputs to the multiple telescopes by dividing a single laser beam and to systems in which the inputs to the telescopes and multiple, phase-locked laser beams. The approach is also compatible with single line and multi-line lasers, and it does not entail stringent alignment …

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Atomic Hydrogen In A Uniform Magnetic Field: Low-Lying Energy Levels For Fields Above 109 G, Chih-Ray Liu, Anthony F. Starace Jan 1987

Atomic Hydrogen In A Uniform Magnetic Field: Low-Lying Energy Levels For Fields Above 109 G, Chih-Ray Liu, Anthony F. Starace

Anthony F. Starace Publications

The energies and wave functions of the 1s, 2s, 2p(ml = 0), and 2p(ml = ±1) levels of hydrogen in a uniform magnetic field B (109 G ≤ B ≤ 1012 G) are calculated in two cylindrical adiabatic approximations, each of which includes the influence of the Coulomb field on the radial motion of the electron. For the lowest levels of each symmetry [i.e., the 1s, 2p(ml = 0) and 2p(ml = ±1) levels] our calculations provide rigorously both upper and lower bounds on …

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Stability-Instability Transitions In Hamiltonian Systems Of N Dimensions, Foek T. Hioe, Z Deng Jan 1987

Stability-Instability Transitions In Hamiltonian Systems Of N Dimensions, Foek T. Hioe, Z Deng

Physics Faculty/Staff Publications

We show analytically that for a class of simple periodic motions in a general Hamiltonian system of n dimensions, if C is a parameter of the system and Cz one of its generally many critical values at which the motion undergoes a stability-instability transition, the behavior of the largest Lyapunov exponent p as C approaches Ce from the unstable region is given by µ, =constX |~ C—Cp |β where β= 1/2, independent of the transition point, type of transitions, or the dimensionality of the system. We present numerical results for a three-dimensional Harniltonian system which exhibits three types …

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Non-Abelian Bosonization: Current Correlation Functions, Lowell S. Brown, Rafael I. Nepomechie Jan 1987

Non-Abelian Bosonization: Current Correlation Functions, Lowell S. Brown, Rafael I. Nepomechie

Physics Articles and Papers

We demonstrate that, in 1+1 dimensions, the effective action produced by massless fermions moving in external gauge potentials is identical with that produced by a suitably defined σ model which includes a Wess-Zumino term. Hence the current correlation functions of the fermion and boson theories are identical.

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Non-Abelian Bosonization: Stress-Energy Correlation Functions, Lowell S. Brown, Gary J. Goldberg, Chaiho P. Rim, Rafael I. Nepomechie Jan 1987

Non-Abelian Bosonization: Stress-Energy Correlation Functions, Lowell S. Brown, Gary J. Goldberg, Chaiho P. Rim, Rafael I. Nepomechie

Physics Articles and Papers

We demonstrate that, in 1+1 dimensions, the effective action produced by massless fermions moving in external gravitational and gauge fields is identical with that produced by a suitably defined σ model which includes a Wess-Zumino term. This equivalence holds provided that the two models have the same conformal anomaly, a condition that we investigate in detail.

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