Digital Commons Network^™

The Nitrogen Dayglow On Mars, Jane L. Fox, Alexander Dalgarno, E. R. Constantinides, G. A. Victor

Physics Faculty Publications

The ultraviolet dayglow spectrum arising from emission of N₂ in the Mars atmosphere is predicted. The intensities are such that a high-resolution spectrum should readily reveal the presence of N₂ at the abundances suggested by the Viking experiments.

Radiative Transition Probabilities Of The 1S2P22P And 1S2P22D States Of The Lithium Isoelectronic Sequence, Jane L. Fox, Alexander Dalgarno

Physics Faculty Publications

A Z-expansion procedure is used to obtain eigenvalues and eigenfunctions for the 1s²2p²P^o, 1s2p²²P, and 1s2p²²D states of the lithium sequence. Expansions in inverse powers of the nuclear charge Z are obtained also for the dipole-matrix elements and oscillator strengths of the 1s²2p²P^o-1s2p²²P and 1s²2p²P^o-1s2p²²D transitions, valid for Z > 3. …

Results Of A Remedial Laboratory Program Based On A Piaget Model For Engineering And Science Freshmen, Robert Gerson

Physics Faculty Research & Creative Works

Engineering and science freshmen who enter our institution with algebra deficiencies have a very low probability of performing satisfactorily in the required college-level calculus course. Two years ago, a remedial one-semester program was conducted for 36 freshmen who were identified by an entrance examination as being weak in algebra. The course was based on the assumption that the students were "concrete" in the Piagetian sense. The main part of the course required a general physics laboratory that provided selected experiences to bridge the concrete-formal gap. After three semesters, 31% of the participants in the course were receiving grades of C …

Effect Of Compliant Wall Motion On Turbulent Boundary Layers, Dennis M. Bushness, Jerry N. Hefner, Robert L. Ash

Mechanical & Aerospace Engineering Faculty Publications

A critical analysis of available compliant wall data which indicated drag reduction under turbulent boundary layers is presented. Detailed structural dynamic calculations suggest that the surfaces responded in a resonant, rather than a compliant, manner. Alternate explanations are given for drag reductions observed in two classes of experiments: (1) flexible pipe flows and (2) water-backed membranes in air. Analysis indicates that the wall motion for the remaining data is typified by short wavelengths in agreement with the requirements of a possible compliant wall drag reduction mechanism recently suggested by Langley. Copyright © 1977 American Institute of Physics.

The Electron-Methyl Group Spin-Spin Interaction, Peter A. Beckmann

Physics Faculty Research and Scholarship

The nuclear spin symmetry conversion transition, whereby a methyl group changes tunnelling state (A↔E) and total nuclear spin (ΔI = ± 1), is made resonant by the flip of an unpaired electron spin (Δms = ± 1). The coupling between an unpaired electron in a free radical and a methyl group in a nearby molecule is via the inter-molecular spin-spin interaction. The matrix elements and transition probabilities for this transition are calculated explicitly. The motivation behind the calculation is to aid in the interpretation of electron spin relaxation experiments in γ-irradiated 4-methyl-2,6-t …

The Haupt Effect: Coupled Rotational And Dipolar Relaxation Of Methyl Groups, Peter A. Beckmann, S. Clough, J. W. Hennel, J. R. Hill

Physics Faculty Research and Scholarship

A theory is described for the dynamic proton dipolar polarization observed by Haupt (1972) in 4-methylpyridine following a sudden temperature change. The theory differs from that of Haupt in assuming that transitions which change the rotational quantum number of the 4-methyl group by +or-3 occur very rapidly, maintaining thermal equilibrium within each of the three subsets of rotational levels corresponding to the three methyl group proton spin symmetry species A, Ea and Eb. The difference of A and E species populations approaches the new equilibrium value slowly and exponentially, following the temperature jump, and generates dipolar polarization in the process. …

Heisenberg Theory Of Ferromagnetism: Constant Coupling Revisited, Harry A. Brown

Physics Faculty Research & Creative Works

The Heinsenberg theory of ferromagnetism has been treated by many types of approximations; one of the more successful is known as constant coupling. The literature constants several different ways of arriving at results like those of the constant-coupling approximation, but proofs that they are indeed equivalent are lacking in some cases. It is shown that two of these methods are equivalent for spin 1/2 and explicitly demonstrated that both yield exactly the constant-coupling results, though simpler in use and concept than the latter. Finally, it is shown that one of the two methods yields the same Curie temperatures as constant …

Interaction Of Electric And Magnetic Charges, I. Adawi

Physics Faculty Research & Creative Works

It is shown classically that in a head-on collision between an electric and a magnetic charge a repulsive polarization force of the form r-5 results (where r is the distance between the charges), if one (both) charge(s) is (are) assigned a finite spherical size. This force leads to a minimum distance of approach and prevents one particle from going through the other, and thus guards against the violation of the conservation of angular momentum. This polarization force is a manifestation of the diamagnetism (diaelectricity) of extended electric (magnetic) charges. © 1977 The American Physical Society.

Light Emission From Atom Beam - Plasma Interactions, Kaare J. Nygaard

Physics Faculty Research & Creative Works

A beam of atoms penetrating a plasma can be considered a line source of contaminants. Atoms excited by the plasma electrons yield information about the spatially resolved electron density and temperature. The light intensity as a function of time and position along the beam can be conveniently observed with an optical multichannel analyzer Since the beam atoms are different from the plasma constituents, the method does not suffer from self-absorption. Copyright © 1977 by The Institute of Electrical and Electronics Engineers, Inc.

Final-State Effects In Carbon Auger Spectra Of Transition-Metal Carbides, M. A. Smith, L. L. Levenson

Physics Faculty Research & Creative Works

The carbon Auger spectra of TiC, VC, and Cr₃C₂ are measured with a resolution of 1.2 eV. Background subtraction is performed, and a deconvolution technique is used to remove energy-dependent broadening from the spectra. An analysis of the data in terms of density-of-states calculations, x-ray emission work, and x-ray photoelectron data shows that final-state effects dominate the Auger spectra. For all of the carbides three peaks are identified as spectral terms resulting directly from final-state hole interactions. Other peaks appearing in the Auger spectra can be identified without final-state considerations. © 1977 The American Physical Society.

Valence-Band Information From The Auger Kvv Spectrum Of Graphite, M. A. Smith, L. L. Levenson

Physics Faculty Research & Creative Works

The Auger KVV and x-ray photoelectron valence-band spectra of atomically clean, well-ordered graphite are measured. After background subtraction is performed and a deconvolution technique is used to remove energy-dependent features from the Auger data, the transition density function is calculated for the graphite valence band. A comparison is made with other experimental work and with a density-of-states calculation. It is found that the transition density closely resembles the density of states if localized hole effects are considered. © 1977 The American Physical Society.

Surface Electromagnetic Waves With Damping. Ii. Anisotropic Media, G. S. Kovener, Ralph William Alexander, I. L. Tyler, Robert John Bell

Physics Faculty Research & Creative Works

The Technique of Plotting the Attenuated-Total-Reflection (ATR) Reflectance as a Function of Both Frequency and Incident Angle using a Three-Dimensional Plot is Applied to Surface Electromagnetic Waves (SEW) in a Uniaxial Material, MnF2. It is Shown that Dispersion Curves Calculated Without Absorption Do Not Completely Describe the ATR Reflectivity. Experimental Data Confirming the Reflectance Surface Features Are Presented. Also, Additional Minima in the Reflectance Surface Not Associated with SEW Are Discussed. © 1977 the American Physical Society.

Existence Of The Dielectric Constant In Rigid-Dipole Fluids: The Functional-Derivative Approach, John D. Ramshaw

Physics Faculty Publications and Presentations

In a previous article [J. Chem. Phys. 57, 2684 (1972)] sufficient conditions were established for the existence of the dielectric constant ɛ in rigid-dipole fluids. One of these conditions was an unrealistic restriction on the angular dependence of the direct correlation function c (12) at short range. Here it is shown that this restriction can be removed without altering the previous conclusions. Consequently, ɛ rigorously exists if c (12) depends only upon relative positions and orientations of molecules 1 and 2, and becomes asymptotic to -φd(12)/kT at long range, where φd(12) is the dipole-dipole potential. The development is based upon …

Λ And K⁰ Production In P↑P Interactions At 6 Gev/C, R. L. Eisner, William J. Fickinger, S. L. Glickman, J. A. Malko, J. F. Owens, D. K. Robinson

Faculty Scholarship

Results on K0 and Λ production in p↑p interactions at 6 GeV are presented. The data are from an exposure of the Argonne 12 ft bubble chamber to a 60% transversely polarized proton beam. Results include data on Λ and K0 inclusive production, and on the reactions p↑p → pΛK+(pΣ0K+). The beam asymmetry parameter for Image is determined to be (−0.52 ± 0.12).

Note On The Van Der Waals Equation, Louis H. Lund

Physics Faculty Research & Creative Works

No abstract provided.

Absolute Doubly Differential Cross Sections For Ejection Of Secondary Electrons From Gases By Electron Impact. I. 100- And 200-Ev Electrons On Helium, M. Eugene Rudd, R. D. Dubois

M. Eugene Rudd Publications

We have measured absolute values of the cross sections for ejection of electrons from helium gas by 100- and 200-eV electrons. These cross sections were measured for emission angles from 10° to 150° and for electron energies from 3 eV to a value equal to the primary energy minus the ionization potential. The measurements were made using a static-gas target and an electrostatic analyzer. The resulting cross sections agree reasonably well with those of Opal, Peterson, and Beaty near 90°, but show the need for an adjustment of their angular distributions. Comparison with Born-approximation calculations of Manson et al. at …

Property And Tort In Nuclear Law Today, Kazimierz Grzybowski, William Dobishinski

Faculty Scholarship

No abstract provided.

Review Of Quantum States Of Atoms, Molecules And Solids, M. Eugene Rudd

M. Eugene Rudd Publications

The subjects of atomic, molecular and solid-state physics have only rarely been treated at an advanced level in a single volume. The notable exception, of course, is John C. Slater’s Quantum Theory of Matter. In the present book the three authors, Michael Morrison, Thomas Estle and Neal Lane, stress the unity among these fields by ernphasizing the concept of electronic quantum states in atoms, diatomic molecules and crystalline solids. Such a combination should be of basic interest to students in a variety of scientific fields and also form the basis for more advanced work in those three subjects themselves. …

Ultraviolet Stimulated Thermoluminescent Response Characteristics Of Aluminum Oxide, Edward Ryan Iii

Masters Theses & Specialist Projects

This investigation has demonstrated that some aluminum oxide crystals have high sensitivity and are well suited for detecting and measuring ultraviolet radiation rates significantly less than .01 µW/cm².

The thermoluminescent glow curve, linearity of response, and fading of the crystals were determined. An action spectrum was performed to determine the relative sensitivities of several crystals in a range of wavelengths from 230 nm to 546 nm.

The sensitivity of the crystals was found to decrease as a function of exposure. \n explanation for the decrease in sensitivity due to the presence of high temperature traps is presented.

This …

Ultraviolet Stimulated Thermoluminescent Response Characteristics Of Aluminum Oxide, Edward Ryan

Masters Theses & Specialist Projects

This investigation has demonstrated that some aluminum oxide crystals have high sensitivity and are well suited for detecting and measuring ultraviolet radiation rates significantly less than 0.1 pW/cm2. The thermoluminescent glow curve, linearity of response, and fading of the crystals were determined. An action spectrum was performed to determine the relative sensitivities of several crystals in a range of wavelengths from 230 nm to 546 nm. The sensitivity of the crystals was found to decrease as a function of exposure. An explanation for the decrease in sensitivity due to the presence of high temperature traps is presented. This investigation has …

Energy Dependence Of Amorphizing Implant Dose In Silicon, John R. Dennis, Edward Boyd Hale

Physics Faculty Research & Creative Works

The radiation-induced transformation from crystalline to amorphous silicon was studied using ion implantation. The ion energy was varied from 20 to 180 keV for Li+, N+, Ne+, Ar+, and Kr +. The energy dependence of the critical amorphizing dose was determined by electron spin resonance. Comparison of the data with theoretical calculations of the energy density deposited into atomic processes showed good agreement. This energy-dependent agreement gave evidence that energy density is important to the transformation at both low and high implantation temperatures.

Synthetic Analogs Of The Active Sites Of Oxidized And Reduced Rubredoxin, Richard B. Frankel, G. C. Papaefthymiou, R. W. Lane, R. H. Holm

Physics

The bischelate monoanion [Fe((SCH₂)₂C₆H₄)₂]^1- contains an unconstrained, near-tetrahedral Fe(III)-S₄ coordination unit (similar to the Fe-S₄ coordinationunit occurring in rubredoxin proteins) and exhibits the Fe(III)/Fe(II) redox couple. Mossbauer parameters at 77 K are isomer shift δ = 0.13 mm/s (relative to iron metal) and electric quadrupole splitting ΔE_Q = 0.57 mm/s. Application of an external magnetic field parallel to the direction of observation at 4.2 K induces a saturation magnetic hyperfine field of - 380 kOe. Upon reduction to the dianion [Fe((SCH₂)₂C …

Model Fe(Iii) Porphyrin Systems: Axial Ligation In Oxidized Cytochrome P-450.S, G. C. Papaefthymiou, Richard B. Frankel, S. Foner, S. C. Tang, S. Koch, R. H. Holm

Physics

In an effort to develop useful experimental criteria to distinguish among the viable axial ligation possibilities of O, N, and S coordination in oxidized cytochrome P-450. S (substrate-bound, high-spin), syntheticmodel compounds with O-(Fe(PPIXDME) (OEt) and Fe(PPIXDME) (OC₆H₄NO₂)) and S-(Fe(PPIXDME) (S₆H₄NO₂) and Fe(OEP) (SPh)) donor axial ligands were prepared and studied by Mössbauer spectroscopy. Ferric hemoglobin and myoglobin were used as model compounds with N-axial coordination. The isomer shifts (δ) and quadrupole splittings (ΔE_Q) observed are typical of high-spin Fe(III) porphyrins and are comparable with results …

Computer Model Of A Fast Toroidal Plasma Compression, With Application To The Topolotron, H. Mark Nelson, Keith H. Brown, Charles A. Hart

Faculty Publications

The method is developed for a comuputer sequence which models a fast toroidal theta or screw pinch for a highly conducting axially symmetric plasma. The computer sequence takes into account the self-inductances of the plasma and the external conductors which drive the compression as well as the mutual inductance which electromagnetically couples the two. The computer sequence is divided into three phases: a snowplow compression phase, an adiabatic compression phase, and a crowbarred circuit phase. The computer sequence is applied to a topolotron and an example is given of a magnetohydrodynamic equilibrium geometry for which the plasma surface possesses an …

Excitation Of The N=2 State Of Atomic Hydrogen By Electron Impact In The Distorted-Wave Approximation, Ralph V. Calhoun, Don H. Madison, W. Neil Shelton

Physics Faculty Research & Creative Works

The differential cross sections for excitation of the n=2 state of atomic hydrogen by the impact of electrons with energies of 54, 100, 136, and 200 eV are calculated in the distorted-wave approximation with exchange included. Cross sections for excitation of the 2s_1/2, 2p_1/2, and 2p_3/2 states are calculated and summed to give the n=2 differential cross sections. The results of this calculation are compared with previous theoretical calculations and with recent absolute experimental data.

Electron Transmission Studies Of The Negative Ion States Of Substituted Benzenes In The Gas Phase, Kenneth D. Jordan, J.A. Michejda, Paul Burrow

Paul Burrow Publications

Temporary negative ions of benzene, aniline, phenol, anisole, fluoro-, chloro-, and bromobenzene, formed in the gas phase by capture of electrons into the low-lying π* orbitals, are studied by means of electron transmission spectroscopy. The electron affinities are determined and their relative values are interpreted in terms of resonance and inductive effects.

Electronic And Magnetic Properties Of Amorphous And Crystalline Zr40Cu60-XFeX Alloys, F.R. Szofran, G.R. Gruzalski, John W. Weymouth, David J. Sellmyer, B.C. Giessen

David Sellmyer Publications

Electronic states and localized magnetic moments and their interactions were studied in amorphous and crystalline Zr₄₀Cu_60-xFe_x alloys for 0≤x≤12. Electrical resistivity, magnetic susceptibility, and high-field magnetization measurements were performed. In the dilute crystalline alloys Curie-Weiss behavior is seen in the susceptibility and is associated with localized moments (μ_eff≈3μ_B) on the iron atoms. At higher iron concentrations ferromagnetism is observed. Curie-Weiss behavior also is seen in the susceptibility of the dilute (0eff≈0.7μ_B). There is some evidence that the local environment of the Fe atoms is important and may depend …

Calculated Temperature Of Grid Lateral Wires In Microwave Power Triodes, Jewell Tucker

Masters Theses & Specialist Projects

In microwave power triodes the grid drive power causes grid lateral wire heating. This development calculates the temperature of the wire as a function of the drive power, physical dimensions and characteristics of the wire material, for the following boundary conditions:

I. Constant grid drive, grid lateral wire of infinite length not connected to a heat sink.

II. Same as I except the wire is of finite length brazed to a grid frame.

III. The grid excitation in the form of pulses, and the grid lateral wire of finite length brazed to a grid frame.

the equations were verified experimentally …

A Comparison Of The Rough Sphere Rotational Diffusion Model With Experimental Results For Liquid Methyl Iodide, Dane R. Jones, Scott L. Whittenburg, C. H. Wang

Chemistry and Biochemistry Faculty Publications

No abstract available.

Behavior Of A Manganin Coil At Elevated Temperatures And Pressures, Jonathan D. Weiss, Daniel L. Decker, H. B. Vanfleet

Faculty Publications

We have determined the temperature dependence in the first-order pressure coefficient of a manganin coil to be dBetaB/dT= (4.2±0.8) ×10^-7 (kbar degrees C)^-1 in the equation R (T,P) =R (T,0)(1+BetaP+GammaP2), where R (T,P) is the coil resistance at temperature T and pressure P. The measurements were performed by simultaneously measuring the coil resistance and temperature at the transitions of mercury and bismuth, which were observed by differential thermal analysis.