Digital Commons Network^™

Effective Field Model For Ising Ferromagnets: Influence Of Triplet Correlations, G. B. Taggart

Physics Publications

We use an effective field model which explicitly incorporates correlations to determine the critical temperatures for Ising ferromagnets on the common lattices. We specifically retain only the first nontrivial odd correlation function, i.e., the triplet correlation function, while neglecting higher order correlations. Within this approximation, assuming the equivalence of triplet correlations involving both central and noncentral sites in the nearest neighbor cluster yields values for the critical temperature below the Bethe approximations for z⩾4. Likewise, assuming the inequivalence of triplet correlations involving the central and noncentral sites yields values of the critical temperature only slightly higher than the Bethe approximation …

The Role Of Diffusion In The Binding Of Carbon Monoxide To Protoheme In High-Viscosity Solvents, David Peak

All Physics Faculty Publications

Studies of the flash photolysis of heme‐bearing proteins have often assessed the role of ligand diffusion in very approximate ways and a disagreement about the importance of ligand diffusion exists in the literature as a result. This paper provides a somewhat more sytematic analysis of diffusional effects than has been given previously for the simple case of ligand–protoheme binding. The model developed here is fit to the available data for the ligand CO in glycerol–water solvents. The fit suggests that diffusional motions become important for the kinetics of this system for temperatures below 270 K and that these motions are …

Travelling-Wave Sub-Doppler Excited Molecule Energy Transfer Spectroscopy, Khalid Iqbal, Shannon G. Lieb, J. W. Bevan

Scholarship and Professional Work - LAS

A general formulation of traveling‐wave sub‐Doppler excited molecule energy transferspectroscopy is presented. The line profile analysis is applied to that determined experimentally for the R(22) ν3 HCN transition. Pn the noise equivalent power of the detector is demonstrated to be ⩽10−12 W. Finally, the technique is applied to resolve the KsR(7) ν1 transition head in NH3.

A Stratospheric Chemical Instability, Jane L. Fox, Steven C. Wofsy, Michael B. Mcelroy, Michael J. Prather

Physics Faculty Publications

The equations which determine partitioning of Cl_x in steady state have multiple (three) solutions under conditions which might arise in the high-latitude winter stratosphere. Two of these solutions are stable, one is unstable, to infinitesimal perturbations. The relative stability of solutions is examined by subjecting the system to finite perturbations. The more stable solution is found to eliminate the less stable when semi-infinite volumes of the two solutions are placed in contact. The high-ClO, low-NO₂ solution is more stable under most conditions. Transitions from less to more stable states are slow in winter but may occur more rapidly …

Atomic Carbon In The Atmosphere Of Venus, Jane L. Fox

Physics Faculty Publications

The densities of atomic carbon in the Venusian thermosphere are computed for a model which includes both chemistry and transport. The maximum density of C is 2.8×10⁷ cm⁻³ near 150 km for an assumed O₂ mixing ratio of 1×10⁻⁴. Photoionization of atomic carbon is found to be the major source of C⁺ above 200 km, and resonance scattering of sunlight by atomic carbon may be the major source of the C I emissions at 1561 Å, 1657 Å, and 1931 Å. The computed C⁺ densities are found to be in substantial agreement with …

Measurement Of The Wear Properties Of Metallic Solids With A Falex Lubricant Testing Machine, Edward Boyd Hale, Chun-Ping John Meng, Ronald A. Kohser

Physics Faculty Research & Creative Works

A modified Falex Lubricant Testing Machine has been used to determine wear properties of metallic solids. In particular, wear mass loss, wear volume loss, wear rates, and other parameters have been determined for a basic steel, as heat treated and after ion implantation. Wear rate improvements of more than an order of magnitude were found in a nickel-chrome steel (SAE 3135) implanted with 2.5x10¹⁷ N⁺₂/cm². Wear tests were conducted with a cylinder-in-groove geometry in a mild lubricating oil with loads greater than 540 N, which corresponded to pressures which exceeded 10⁸N/m^{2 …}

A Laser Interferometric Study Of Electric Field Effects On Methane-Oxygen Flame Plasmas, Mark D. Prairie

Masters Theses

A laser interferometer is developed to study the refractive index field, aerodynamic structure, and three dimensional temperature profile of a methane-oxygen flame system under the influence of D.C. electric fields. A combined graphical-numerical method is used to transform the observed interference patterns into radial temperature distributions. The results indicate that the electric field exerts a marked influence on the flame stability, geometry, and charged particle flow. Experimental evidence shows that these effects are most apparent under fuel rich conditions. It is suggested an electric field may change the concentration gradients of reacting species, leading to an altered course of fuel …

A Study Of The Critical Cluster Size For Water Monolayer Clusters On A Model Agi Basal Substrate, Richard C. Ward, Barbara N. Hale, Sergio Terrazas

Physics Faculty Research & Creative Works

We present a formalism and estimate a critical cluster size for water monolayer formation on a (rigid) model AgI basal substrate. The formalism is modified from that developed for vapor clusters [B. N. Hale and R. C. Ward, J. Stat. Phys. 28, 487 (1982)] and uses a Metropolis Monte Carlo method developed by Squire and Hoover [J. Chem. Phys. 50, 701 (1969)] to determine (Helmholtz) free energy differences for clusters containing n and n-1 molecules. Calculations for clusters of n=1, 2, 3, 4, 6, and 24 water molecules on a model AgI basal face at 265 K are …

Production Of Highly Charged Rare-Gas Recoil Ions By 1.4-Mev/Amu U44+, A. S. Schlachter, W. Groh, A. Müller, H. F. Beyer, R. Mann, Ronald E. Olson

Physics Faculty Research & Creative Works

Recoil-ion-production cross sections in rare gases are measured for 1.4-MeV/amu U44+ ions and are calculated for 1-5-MeV/amu projectiles in charge state 44 + with the use of the classical-trajectory Monte Carlo method and the independent-electron model. The calculations reasonably predict the net-charge-production cross sections, which exceed 10-13 cm2 for the heavy rare gases; the calculations are found to underestimate the cross sections for low-charge-state recoil ions and to overestimate the cross sections for high-charge-state recoil ions. The experimental cross sections for production of highly charged recoil ions are found to be large, e.g., greater than 1x10-16 cm2 for production of …

D- Production By Charge Transfer Of (0.3 - 3)-Kev D+ In Thick Alkaline-Earth Vapor Targets: Interaction Energies For Cah+, Cah, And Cah-, R. (Robert) H. Mcfarland, A. S. Schlachter, J. W. Stearns, B. Liu, R. (Ronald) E. Olson

Physics Faculty Research & Creative Works

Equilibrium charge-state fractions of energetic deuterium ions and atoms emerging from alkaline-earth (magnesium, calcium, strontium, and barium) vapor targets are reported in the range of 0.3- to 3-keV incident D+ energy. Deuterium negative-ion production in thick barium and calcium vapor targets equals similar production in cesium vapor (34%). Moreover, the maximum D- production in strontium vapor exceeds that for all other known gas or vapor targets and reaches 50% at 500 eV. Theory does not quantitatively describe these results, although ab initio molecular-interaction-energy calculations on the neutral and negative-ion CaH systems lead to the prediction of large D- yields at …

Determination Of The Absolute Structure Factor For The Forbidden (222) Reflection In Silicon Using 0.12-Γ Rays, R. W. Alkire, W. (William) B. Yelon, J. R. Schneider

Physics Faculty Research & Creative Works

A room-temperature determination of the absolute structure factor for the forbidden (222) reflection in silicon has been conducted at the University of Missouri Research Reactor with 103-keV gamma rays. The measured structure factor of F(222)=1.456 is in excellent agreement with five of the earlier intensity measurements and is significantly different from any value determined using Pendellösung techniques. An increase in accuracy over previous intensity measurements by a factor of between 2 and 10 has been achieved and is made possible through the use of monoenergetic, short-wavelength gamma rays, which allow absolute measurements to be made in Laue geometry on relatively …

Phaseautomodulation In Magnesium, Alexander Aning, Tetsuro Suzuki, Manfred Wuttig

Physics Faculty Research & Creative Works

No abstract provided.

Homogeneous Nucleation Of Ethanol, John L. Schmitt, G. W. Adams, R. A. Zalabsky

Physics Faculty Research & Creative Works

The authors have used an expansion cloud chamber to measure homogeneous nucleation rate as a function of temperature and supersaturation in ethanol. Nucleation rates from 102 to 105 drops/cm3 sec were measured in the temperature range 252-272 °K. An empirical functional fit to the data is used to extrapolate for comparison with other data in the literature at a nucleation rate of 1 drop/cm3 sec and to compare with the predictions of the classical Becker-Doring homogeneous nucleation theory. A full listing of the data and thermodynamics constants used in the reduction of the data is given in an appendix. © …

A Note On The Use Of A Photoelectric Counter For Total Particle Counting, Josef Podzimek, Paul C. Yue

Physics Faculty Research & Creative Works

The ability of the Nolan-Pollak counter to function as a "total" particle counter was investigated. Comparison with the UMR Absolute Aitken Nuclei Counter operated at an expansion pressure ratio of 1.33 revealed that in mean, the N-P counter measurements (at an expansion pressure ratio of 1.21) were 30% less. This correction, however, depends on particle nature, concentration and size distribution and assumes that particle losses in the central part of the UMRAAN counter are negligible. © 1982.

The University Of Missouri-Rolla, Absolute Aitken Nucleus Counter, John L. Schmitt, James L. Kassner, Josef Podzimek

Physics Faculty Research & Creative Works

The authors discuss the expansion cloud chamber system known as the University of Missouri-Rolla-absolute Aitken nucleus counter. A review of the properties of an expansion chamber and how it creates a supersaturation are given and a critical examination is made of the assumptions in its operation, e.g. adiabaticity of the expansion. The design of the chamber is described in detail and an analysis of the propagation of errors is given for quantities measured and calculated. A short review of the performance of the chamber and some general comments relative to comparisons with other Aitken nucleus counting instruments are given. The …

Electron-Capture Collisions Of H+ With Ground- And Excited-State Na, M. Kimura, Ronald E. Olson, J. Pascale

Physics Faculty Research & Creative Works

Pseudopotential molecular-structure calculations have been used to obtain the low-lying interaction energies for NaH+. The wave functions were used to calculate accurate radial and rotational coupling matrix elements. Scattering calculations which include electron translational factors were performed using up to eight coupled channels for laboratory energies 0.1 to 10 keV. Electron capture from ground-state Na 3s yields cross sections in the 10-15-cm2 range of which the dominant products are H 2s and H 2p. Electron capture from excited Na 3p does not show an enhanced cross section relative to capture from the ground state even though the energy gap E(R=) …

Absolute Theory Of Relativity & Parameterized Special Theory Of Relativity & Noninertial Multirelativity, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In this book we present our 1972 hypothesis that there is no speed barrier in the universe and one can construct arbitrary speeds -

thus refuting the speed of light postulate.

While Einstein considered a relative space and relative time but the ultimate speed

of light, we do the opposite: we consider an absolute time and absolute space but no

ultimate speed, and we call it the Absolute Theory of Relativity (ATR). The ATR has no time dilation, no length contraction, no relativity of simultaneity, and no relativistic paradoxes.

We then parameterize Einstein’s thought experiment with atomic clocks,

supposing that …

Coloured Monopoles From Fractional Charges In Ocd, A. P. Balachandran, V. Parameswaran Nair, C. G. Trahern

Publications and Research

In a recent paper, Slansky et al. have suggested that SU(3)c may be broken to SO(3) X Z, in order to explain the possible existence of fractionally charged states. We point out that there are low mass monopoles associated with such a symmetry breakdown and discuss their properties. Such states may be observable at LEP if not at PETRA energies.

Existence Of The Dielectric Constant In Fluids Of Classical Deformable Molecules, John D. Ramshaw

Physics Faculty Publications and Presentations

The existence of the dielectric constant epsilon is investigated for fluids composed of classical deformable (polarizable) molecules. The development is based upon generalized functional-derivative relations which involve joint distributions in molecular positions r/sub k/ and dipole moments ..mu../sub k/. Sufficient conditions for the existence of epsilon are expressed in terms of the generalized direct correlation function c(12) = c(r/sub 1/, ..mu../sub 1/; r/sub 2/, ..mu../sub 2/). It is found that epsilon exists if -kTc(12) depends only on relative positions and dipole moment directions (in addition to Vertical Bar..mu../sub 1/Vertical Bar and Vertical Bar..mu../sub 2/Vertical Bar), and becomes asymptotic to the …

Fine Structure Of Rydberg States. V. N=5 And 6f And G States Of He4, John W. Farley, Doreen A. Weinberger, Shin Sheng Tarng, Nancy D. Piltch, William H. Wing

Physics: Faculty Publications

We have made 17 new high-precision measurements of the nF-nG intervals (n=5,6) of neutral He4 using the microwave-optical method. The rms one-standard-deviation experimental uncertainty for the transitions reported here is 188 kHz (14 ppm). The new measurements agree with the predictions of a least-squares fit to previous experimental data, and are up to 40 times more precise. The nF-nG manifold is now known experimentally to better than 1 MHz for all values of the quantum numbers. The precision of the experimental measurement exceeds that of the best currently available theory by approximately three orders of magnitude.

Picosecond Laser Pulse Irradiation Of Crystalline Silicon, K. L. Merkle, H. Baumgart, R.H. Uebbing, F. Phillipp

Electrical & Computer Engineering Faculty Publications

Morphology changes introduced by picosecond laser pulses at λ = 532 nm and 355 nm in (111) and (100) silicon samples are studied by means of optical and high-voltage electron microscopy. Depending on energy fluence, orientation and wavelength, amorphous or highly defective regions may be created. From an analysis of damage thresholds and damage depth distributions it is concluded that melting and energy confinement precedes the formation of the structural changes.

On The Curie Temperatures Of Amorphous Ferromagnets, Harry A. Brown

Physics Faculty Research & Creative Works

No abstract provided.

Rare-Gas, Collision-Induced Shifts Of The Nd States Of Sodium, D. J. Krebs, Laird D. Schearer

Physics Faculty Research & Creative Works

We have measured line shifts of the 3P-nD transitions in sodium induced by collisions with helium, argon, and krypton for n=5 to 18. The shifts of the diffuse series transitions increase rapidly with principal quantum number and asymptotically approach the limit predicted by the Fermi model at high quantum numbers. © 1982 The American Physical Society.

Molecular Treatment Of Electron Capture By Protons From The Ground And Excited States Of Alkali-Metal Atoms, M. Kimura, Ronald E. Olson, J. Pascale

Physics Faculty Research & Creative Works

Electron-capture cross sections for H+ plus alkali-metal atom (Na, K, Rb, and Cs) systems have been computed for projectile energies from 10 eV to 10 keV. An impact parameter perturbed-stationary-state theory using molecular states that incorporate electron translation factors was used to calculate the cross sections. The wave functions were generated by employing the pseudopotential method. These yield equilibrium parameters Re and De for the A +2 molecular state that are in good agreement with ab initio results. Interaction energies are also presented for the LiH+ system. Basis sets of up to eight molecular states were used to calculate the …

Electron Density Measurements In A Laser Induced Na Plasma, D. J. Krebs, Laird D. Schearer

Physics Faculty Research & Creative Works

The optical emission spectrum of a recombining Na plasma is observed. The shift and broadening of the spectral line emission due to electron collisions is observed. Electron densities on the order of 5x1014 cm -3 are calculated from the shift measurements. The results agree well with electron densities obtained in the same system from Saha plots of excited state densities. © 1982 American Institute of Physics.

A Study Of Poly(P‐Xylylene)‐Coated Asf5‐Doped Polyacetylene, J. E. Osterholm, H. Yasuda, L. L. Levenson

Physics Faculty Research & Creative Works

Electrical conductivity measurements and scanning electron microscopy have been used to study uncoated and poly(p‐xylylene)‐coated samples of polyacetylene doped with AsF5. These initial results indicate a considerable reduction in the decay rate of conductivity in the presence of oxygen as well as a decreased rate of thermal decomposition of the dopant when heated between 50°C and 115°C in vacuum by the coating. Copyright © 1982 John Wiley & Sons, Inc.

Comparison Of Several Aitken Nuclei Counters, Josef Podzimek, John C. Carstens, P. C. Yue

Physics Faculty Research & Creative Works

The basic thermodynamical processes leading to the formation of droplets in the central part of the Nolan-Pollak counter are analyzed in some detail. The comparison of the UMR-Absolute Aitken Nuclei counter with Nolan-Pollak, General Electric and Gardner counters showed consistently higher counts of the UMR-AAN counter. The mean deviations varied between 20% and 50% depending on the type of the counter, nuclei concentration and nature. Several observations are made on ultrafine particle counting. © 1981.

Magnetotactic Bacteria, Richard B. Frankel

Physics

No abstract provided.

A Dwba Study Of Atom-Diatom Rearrangement Collisions, Randall Wayne Emmons

Doctoral Dissertations

"The role of the transferred angular momentum in state-to-state atom-diatom reactive scattering is investigated. Using the F+H₂ reactive system in this model study, it is found that many features in the state-testate differential and total cross-sections can be qualitatively explained. In particular, a maximum total cross-section occurring in a vibrational manifold of HF can be shown to occur due to an angular momentum match"-- Abstract, p. ii

The Heterogeneous Nucleation Of Ice On Ion Implanted Silicon, William Henry Stinebaugh

Doctoral Dissertations

"Ice crystal nucleation on 1 80 keV Si⁺ ion implanted silicon was investigated experimentally at three different temperatures: T = - 20 °, - 24 °, and -30 ° C. The ion doses ranged from 4 .0 x 10¹⁴ ions/cm² to 5 .0 x 10¹⁵ ions/cm². The supersaturation dependence of ice nucleation on the ion implanted samples at these three temperatures was observed by controlling the substrate temperature and relative humidity independently.

An enhanced ice nucleation activity was observed on samples implanted with ion doses in the range of (1.6 - 2.0) x 10 …