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Static Equilibrium Conditions For A Rigid-Ion Crystal, L. L. Boyer, John R. Hardy

John R. Hardy Papers

The equilibrium requirements for a static ionic crystal impose a number of constraints on the short-range forces which become increasingly more important when one is dealing with complex structures. These constraints are presented and discussed for a general rigid-ion lattice, and a specific discussion is presented for the wurtzite structure.

Determination Of The Origin Of The 10.6-Pm Absorption In C02 Laser Window Materials, John R. Hardy, B. S. Agrawal

John R. Hardy Papers

Theoretical studies are presented which show that it should be possible to determine whether the absorption at 10.6 pm in alkali halides is due to impurities or whether it is intrinsic. These studies show that the temperature dependence of the measured absorption should be very different for intrinsic multiphonon absorption as compared with defect-activated absorption.

Projected Hartree Product Wavefunctions. Vi. Natural Orbital Ci Expansions In Nonsinglet Cases, R.D. Koller, Gordon A. Gallup

Gordon Gallup Publications

The NSO's and NO's have been determined for some wavefunctions for Li, Be¹⁺, B²⁺, C^{3+ 2}S, and Be ³S wavefunctions containing radial correlation. It is shown how the NO's may be utilized to form rapidly converging CI expansions in general. The role of the NSO's in this problem is discussed. ©1973 The American Institute of Physics

Observation Of A Second-Order Phase Transition And Its Associated P - T Phase Diagram In Liquid He3, Richard A. Webb, T. J. Greytak, R. T. Johnson, J. C. Wheatley

Faculty Publications

A specific-heat "discontinuity" is observed in liquid He³ from 241 lb/in.2 to the melting pressure in the temperature range 2-3 mK.

Distorted-Wave Approximation And Its Application To The Differential And Integrated Cross Sections For Electron-Impact Excitation Of The 2¹P State Of Helium, Don H. Madison, W. Neil Shelton

Physics Faculty Research & Creative Works

Theoretical results are given for the application of the distorted-wave approximation to electron-atom impact excitation for transitions from an L-S coupled initial state to an arbitrarily coupled final state. Expressions for the differential cross section and spin polarization of the emitted electrons are given for unpolarized electron beams incident upon unpolarized atoms. These results are applied to excitation of helium from its ground state to the 1s2p¹P₁ excited state for incident-electron energies between 26.5 and 300 eV. The results are compared with previous theoretical and experimental works. It is found that the distorted-wave calculation is superior to …

Radiative And Predissociative Lifetimes Of The A ²Σ+ State Of Oh, Richard Orlin Sutherland, Richard A. Anderson

Chemistry Faculty Research & Creative Works

Lifetime measurements have been made on the A 2Σ+ state of OH by the delayed coincidence technique in conjunction with an interrupted rf discharge through water vapor. Lifetimes are reported for rotational states up to K=29 and K=20 in the ν=0 and ν=1 vibrational levels, respectively, and on the unresolved levels of ν=2. A predissociation, previously predicted from relative intensity measurements, resulting from a curve crossing by the repulsive 4Σ− state, was observed for the rotational states above K=23 of ν=0, for those above K=14 of ν=1, and for all those of ν=2. These lifetime data are discussed qualitatively in …

Spin Polarization And Differential Cross Section For Electron-Impact Excitation Of The 6s6p ¹P₁ State Of Mercury: Distorted-Wave Treatment, Don H. Madison, W. Neil Shelton

Physics Faculty Research & Creative Works

The results of the distorted-wave theory for electron-impact excitation of atoms are applied to the excitation of the 6s6p ¹P₁ state of mercury. The spin polarization and the differential cross section are given for unpolarized incident electron beams with energies between 25 and 180 eV. The distorted-wave results are compared with experimental data, and good agreement is found for both the spin polarization and differential cross section.

Absolute Line Strengths By Analysis Of Lu-Fano Plots With Application To Excited State Transitions In Neon, Anthony F. Starace

Anthony F. Starace Publications

Using energy eigenfunctions obtained by semi-empirical analysis of the Lu-Fano plot of energy level positions and employing the Coulomb approximation of Bates and Damgaard, we calculate absolute line strengths for transitions between the neon two-channel Rydberg series 2p⁵(²P_3/2,1/2)ns J = 1 and 2p⁵ (²P_3/2,1/2)n′ p J = 0 for n, n' = 3,4. Each Rydberg series is analyzed separately to obtain a set of five parameters which completely define the energy eigenfunctions for all values of n and n'. Interactions between the ns J = 1 …

Brief Theory Of Coherent Processor, Richard C. Heyser

Unpublished Writings

The particular coherent data processor which is to be discussed relies heavily upon several basic concepts. These concepts represent a departure from conventional practice and hence the theoretical description must await their presentation in order to gain some continuity. We will accordingly present the underlying assumptions and signal physics prior to description of the processor itself.

Quasifree (P,Pα) Scattering On ⁶Li, ²⁴Mg, ²⁸Si, ⁴⁰Ca, ¹⁴⁰Ce, And ²³²Th At 156 Mev, D. Bachelier, M. Bernas, Oleksa-Myron Bilaniuk, J. L. Boyard, J. C. Jourdain, P. Radvanyi

Physics & Astronomy Faculty Works

Knockout of α particles by 156-MeV protons from ⁶Li, ²⁴Mg, ²⁸Si, ⁴⁰Ca, ¹⁴⁰Ce, and ²³²Th has been used to investigate the A dependence of α clustering in nuclei. Protons and α particles were detected in coincidence under conditions of quasifree scattering. Corresponding reaction cross sections were measured. Cross sections for ²⁴Mg and ⁴⁰Ca were found to be about 2 orders of magnitude lower than for ⁶Li. The cross section for ²⁸Si was found to be about 3 times lower than that for ²⁴Mg and ⁴⁰Ca. Upper limits of the integrated cross sections for ¹⁴⁰Ce and ²³²U are still compatible with …

Carbon Interstitial In The Diamond Lattice, C Weigel, David Peak, J W. Corbett, R P. Messmer, G D. Watkins

All Physics Faculty Publications

Linear-combination-of-atomic-orbitals-molecular-orbitals cluster calculations using the extended Hückel theory are carried out for the interstitial carbon in the diamond lattice. The results suggest that the interstitial configuration is not the tetrahedral or hexagonal site, as has been previously assumed, but is instead an "interstitialcy" configuration, i.e., either a split- 〈100〉 interstitial (which our results favor) or a bond-centered interstitial. The predicted minimum-energy configuration changes with charge state, suggesting that the interstitial in the diamond lattice is a possible example of the Bourgoin mechanism of athermal migration of a defect in the presence of ionizing radiation.

Ua77/1 Western Alumnus, Vol. 43, No. 2, Wku Alumni Association

WKU Administration Documents

WKU alumni magazine. Features the following articles:

• Armstrong, Don. Engineering Technology Accredited
• Martin, Vernon & Don Armstrong. Public Affairs Aids Counties
• Distinguished Alumnus Julian Goodman
• Gray, David. WKU Physicist Invents Ultraviolet Dosimeter - William Buckman
• Richards, Jim. Why Recruit the Junior Colleges?
• Pageantry, Nostalgia & Victory - Homecoming
• Just, Paul. The Red and Gray Orchestra
• Ivan Wilson Center for Fine Arts, Dedication
• Hood, Gordon. The Ivan Wilson Center
• Downing, Dero. A Dedication Response
• Downing, Dero. Awareness & Willingness
• Dickey, Debbie. A Renewal of the Spirit
• Sutherland, David. Appalachia, A Stronghold of Early American Folk Culture
• Cann, Kenneth. If It's Guatemala …

Autoionization Of He And Autodetachment Of He- Following Bombardment By H+, H2+, He+, And He Atoms, F. D. Schowengerdt, S. R. Smart, M. Eugene Rudd

M. Eugene Rudd Publications

Presented here are experimental results of a study of the systematics of electron emission from discrete states of He and He- as produced by H⁺, H₂⁺, He⁺, and He impacts. The results were obtained by energy analysis of the electrons emitted at angles of 10° to 160°. Projectile energies ranged from 20 to 150 keV. Differential and integrated cross sections are presented for emission of electrons from the 2s² (¹S), 2s2p(³P), the sum of the 2p² (¹D) and 2s2p(¹P) autoionizing levels of He, …

Projected Hartree Product Wavefunctions. Viii. Relationship Of Dods And Scf Orbitals For Be, Gordon A. Gallup

Gordon Gallup Publications

Projected Hartree product wavefunctions. VIII. Relationship of DODS and SCF orbitals for Be

Ionization‐Enhanced Diffusion: Ion Implantation In Semiconductors, J Bourgoin, David Peak, J W. Corbett

All Physics Faculty Publications

A model for the diffusion of implanted interstitials during implantation is introduced and shown to be able to account for the tails observed in ion profiles. It is argued that mechanisms of ionization‐enhanced diffusion can explain some of the anomalous diffusion mechanisms observed in semiconductors. Indications for the existence of such mechanisms in the field of ion implantation in semiconductors are discussed.

Penning Ionization Of Zn And Cd By Noble-Gas Metastable Atoms, L. A. Riseberg, William F. Parks, Laird D. Schearer

Physics Faculty Research & Creative Works

The Penning-ionization cross sections for He, Ne, Ar, and Kr metastable atoms with Zn and Cd have been measured in a pulsed afterglow. Within the framework of existing theories we have determined those parameters which are of importance in collisions of this type. We find that our data are internally consistent if the cross sections are proportional to the cube of the "hard-sphere" radii and the effects of selection rules are included. A theoretical basis for this dependence is suggested. © 1973 The American Physical Society.

Some Implications Of The Second Law Of Thermodynamics, Nancy Barklage

Student Scholarship

Thermodynamics is the branch of science concerned with energy changes that accompany all natural processes. While there are three primary laws, the Second Law of Thermodynamics is the most far-reaching due to its influence on the direction of time and its philosophical implications for life and the universe. Central to this law is the concept of entropy, which serves as a measure of disorder or randomness within a system. All spontaneous processes are irreversible and naturally progress toward a state of maximum entropy and lowest energy. 

One significant implication of the Second Law involves the origin of life. While the …

Appendix A: The Use Of The Personalized System Of Instruction (Psi)

Calculus-Based General Physics

STUDY MODULES FOR THE USE OF THESE CBP MODULES

Recommended

1. What is the Philosophy of PSI?

2. How Do I Manage This System?

3. The Care and Feeding of Student Tutors

Optional

4. How to Plan the Content of a Keller Plan Course

5. How to Design a Study Module

6. How to Write Learning Objectives

Temperature Dependence Of The Formation Of An Amorphous Layer In Ion-Implanted Silicon, Gary Keith Woodward

Masters Theses

"Electron spin resonance (ESR) has been used to study the temperature dependence of the formation of an amorphous damaged layer produced by ion implantation in silicon.

Undoped silicon wafers were implanted with N⁺, Ar⁺, and Kr⁺ ions at 20 keV and dose rates less than .36 µa/cm². Implant temperatures ranged from room temperature to 250°C. ESR measurements were made at room temperature on these wafers. The only ESR signal found was that associated with amorphous silicon. The ESR signal amplitude for a given ion and temperature increased approximately linearly with dose up to …

General Theory Of Diffusion-Controlled Reactions, Gerald Wilemski, Marshall Fixman

Physics Faculty Research & Creative Works

A formal mathematical description of diffusion-controlled bimolecular reactions is presented. The theory is completely general with respect to the kinds of reaction processes that may be considered. Besides the presentation of the general formalism, the paper also contains several examples illustrating the application of the theory to a simple many-particule system for simple catalytic bimolecular reactions, including fluorescence quenching. The manner in which approximate solutions may be obtained is also outlined.

Note On The Poisson Distribution, I. Adawi

Physics Faculty Research & Creative Works

No abstract provided.

Chemical Shift Parameters For Shallow Donors In Semiconductors, Edward Boyd Hale

Physics Faculty Research & Creative Works

A model for a shallow donor impurity in a semiconductor is used to calculate two relationships and several conditions involving the chemical shift parameters. The model is based on the standard effective mass form for the donor electron wave function, the existence of a potential in the chemical cell which may be real, pseudo, or rather general in nature, and a few somewhat restrictive approximations. The parameters, Δ, δ and Λ are theoretically calculated and are shown to be related if the approximations are valid. These parameters determine the 1S multiplet level structure and it is shown how properties of …

Total Electron Impact Ionization Cross Section In Rubidium From Threshold To 250 Ev, Kaare J. Nygaard, Yu Bong Hahn

Physics Faculty Research & Creative Works

A study of ionization in rubidium has been made in a crossed atom-electron beam apparatus. At an electron energy of about 10 eV there is a maximum in the cross section corresponding to the maximum probability for removal of the 5s valence electron. At 16.5 eV we have observed a new peak that is caused by the mechanism of autoionization. For energies below 30 eV there is a good agreement, both in shape and magnitude, between the present measurements and the empirical formula of Lotz. The over-all uncertainty in the measurements is ± 12% which is mostly accounted for by …

Production Of Metastable Ions In Cesium-Atom-Electron Collisions, Kaare J. Nygaard, Yu Bong Hahn

Physics Faculty Research & Creative Works

The structure in the total electron-impact ionization cross section in cesium can be partially accounted for by the mechanisms of autoionization and excitation ionization of 5p electrons. For electron energies above 17 eV a large fraction of the ions are metastable and can de detected by Auger emission from a metal surface. The experiment was performed in a cesium-atom-electron crossed-beam apparatus, and the metastable ions were counted with a channel electron multiplier. The metastable-ion count rate was a factor of 100 higher than that due to photons from atomic and ionic transitions. We have measured the over-all excitation function for …

Absolute Differential Elastic- And Inelastic-Scattering Cross Sections In 25-140 Kev He+ + He Collisions, Victor Pol, Walter Kauppila, John T. Park

Physics Faculty Research & Creative Works

Data obtained as energy-loss spectra at angles from 0 to 7.3x10-3 rad (c.m.) with typical energy-loss resolution of 0.7 eV and angular resolution of 2x10-3 rad (c.m.) were used to calculate average differential cross sections dσdΩav for elastic scattering, direct excitation of the individual He(n=2) states, and direct excitation of the He+(n=2) states. The total cross section for excitation of the He(n=2) states obtained by integrating the differential cross sections was found to be 20x10-18 cm2 at 25 keV (lab) decreasing to 7x10-18 cm2 at 140 keV. At incident lab energies below 100 keV the He(2S2) and He(2P3) states dominate …

Molecular Beam Measurements Of Total Collision Cross Sections Of H 22o, William R. Snow, J. T. Dowell, J. G. Chevrenak, H. E. Berek

Physics Faculty Research & Creative Works

The total cross section for H22O-H22O scattering is measured with a supersonic nozzle beam system. The primary beam has a narrow velocity distribution, and the velocity is varied by control of the nozzle temperature. Velocities are determined by time-of-flight techniques. Cross sections obtained are averages over a Maxwellian distribution of the target molecules. Data at three velocities are presented. The cross sections for H2O are surprisingly small, for example, 3.07 x10-14 cm2 at 1x105 cm/sec, indicating little contribution from the dipole-dipole interaction.

On The Effect Of Cesium In Photoionization Laser Plasmas, Kaare J. Nygaard

Physics Faculty Research & Creative Works

A number of photoionization mechanisms and how they can be used to generate large-volume laser plasmas are discussed. Reaction rates for two-step photoionization of the cesium atoms as well as formation of molecular ions (Cs2+) are estimated. The necessary cross-section data were obtained from related research in thermionic energy converters. © 1973, IEEE. All rights reserved.

Laser Scattering Measurements Of Droplet Growth In Binary Mixtures. Ii. H2o And Argon H2o And Helium, M. A. Viettit, Burton Schuster

Physics Faculty Research & Creative Works

Water droplet growth rates in a Wilson cloud chamber were measured in Ar-H2O and He-H2O media. These rates were determined in the size range 0.45-10.0 u.m by detection of oscillations in the intensity of polarized light from a He-Ne laser source scattered at 30° by the droplet population. Pressure and initial temperature were measured in the chamber for use in the computation of three droplet growth theories for comparison to experiment. Experiments were conducted in supersaturations ranging from 1.04 to 3.45.

Possible Applications Of Surface Electromagnetic Waves To Measure Absorption Coefficients, Ralph William Alexander, Robert John Bell, C. A. Ward, James Roger Weaver, I. L. Tyler, B. Fischer

Physics Faculty Research & Creative Works

We Show that Surface Electromagnetic Waves Can Probably Be Used to Measure the Absorption Coefficients of Materials overlaying Metals. the Proposed Experimental Method is Illustrated in the Infrared Frequency Range using Water, Teflon, and Polyethylene as Sample Materials.

The Experimental Determination Of The Eddy Current Effects On The Nuclear Magnetic Resonance Of Aluminum Wires, Mark Allen Butterworth

Dissertations and Theses @ UNI

An experimental determination has been made of the eddy current effects on the nuclear magnetic resonance lineshapes of Al²⁷ wires. Eddy currents in the metal result from the applied radio frequency (r-f) field used to obtain resonance. Due to the induced eddy currents, this r-f magnetic field is attenuated and its phase is shifted as it progresses toward the center of the sample. A quantity defined as the skin depth is a measure of this attenuation. As a result of the attenuation and phase shift of the r-f magnetic field, the resultant lineshape of a given mode of the resonance …