Physical Sciences and Mathematics Commons^™

(On The) Observability Of Cubic (P8) Octaphosphorus, Michael W. Schmidt, Mark S. Gordon

Mark S. Gordon

A recent MNDO calculation predicts that the hypothetical P8 is more stable than the observed gas-phase species P4. The ab initio calculations reported here predict just the opposite but do establish that P8 is more stable than another experimentally known form, P2. The relative enthalpies (kcaljmol) are found to be as follows: 4P2, 72.4; 2P 4, 0; P8, 30.4. A force field analysis proves P8 has a cubic structure. The bond length, vibrational frequencies, and photoelectron spectrum of P8 are predicted.

Equatorial F-Region Zonal Plasma Drifts, Bela G. Fejer, E. Kudeki, D. T. Farley

Bela G. Fejer

We have examined in detail the F region plasma drifts measured at Jicamarca, Peru, during 1978–1981, a period of high solar activity, and compared these drifts with Jicamarca data taken during periods of lower activity, as well as with other equatorial zonal neutral wind and plasma drift measurements. The increase in solar activity causes larger nighttime eastward plasma drifts at Jicamarca and delays the morning reversal time from eastward nighttime to westward daytime drifts. The radar data seem to be in good agreement with nighttime neutral wind measurements made by the DE-2 satellite, but are systematically smaller than spaced receiver …

Advances In Synthetic Polymer Chemistry: New Polymer Types And New Directions, The Sixth Carl S. Marvel Symposium, Otto Vogl, Henry K. Hall

Otto Vogl

No abstract provided.

Polymer Science In Japan: The Hokuriku District And The Remaining Universities Of Japan, Otto Vogl, Kiichi Takemoto

Otto Vogl

No abstract provided.

Specialty Polymers -Present And Future, Otto Vogl, Roger Epton

Otto Vogl

No abstract provided.

Quantum Electrodynamics At Finite Temperature, Jf Donoghue, Br Holstein, Rw Robinett

Barry R Holstein

We present a systematic examination of finite temperature effects in quantum electrodynamics at one loop order. We calculate mass, charge, and wavefunction renormalization, demonstrate the running of the coupling constant at high temperatures, and study the renormalized vertex function and the energy momentum tensor. The confusion in the literature concerning the finite temperature corrections to the electron's magnetic moment is resolved. We also present the finite temperature effects in scalar electrodynamics. Throughout we stress the need to provide a well-defined method to observe a given quantity when interpreting the results of a calculation, and we suggest new techniques which incorporate …

Behavior And Ecological Interactions Of Larval Odonata, Clay L. Pierce, Philip H. Crowley, Dan M. Johnson

Clay L. Pierce

Enallagma aspersum and E. traviatum (Odonata: Coenagrionidae) are the most abundant larval odonates in Bays Mountain Park (Sullivan County, Tennessee, USA), although their spatial distributions are essentially nonoverlapping. E. traviatum coexists with insectivorous fish in a small lake, whereas E. aspersum is restricted to a small fishless pond nearby. Behavioral observations revealed that E. aspersum larvae were more active than E. traviatum, and tended to occupy more conspicuous positions. E. aspersum also engaged in more confrontations than E. traviatum, especially at higher density. In laboratorye xperimentsw ith juvenile bluegills( Lepomism acrochirusa) s predators,E . aspersum larvae were more vulnerable to …

Spectral Properties Of Percolating Central Force Elastic Networks, Anthony Day, R. Tremblay, A.-M. Tremblay

Anthony Roy Day

The exponent describing the low frequency spectrum of vibrations for the central force universality class is computed with both the Coherent Potential Approximation and numerical simulations. The results of both calculations agree surprisingly well.

Reanalysis Of Higgs-Boson-Exchange Models Of Cp Violation, Jf Donoghue, Br Holstein

Barry R Holstein

We reexamine the value of ɛ'/ɛ in models where CP violation is due to the exchange of charged Higgs bosons. Previous work has been flawed by incorrect treatment of the chiral properties of weak amplitudes. We use the effective-chiral-Lagrangian framework to clear up these aspects. The resultant value of ɛ'/ɛ is estimated to be in the neighborhood of ɛ'/ɛ=-0.006, although this estimate could be off by a factor of two or three in either direction. This value is consistent with the present experimental bounds.

Evaluation Of Electrochemical Kinetic Parameters Using The Bond-Henderson-Oldham Global Analysis, Dennis Evans, Mark Anderson

Mark R. Anderson

No abstract is currently available.

Interaction Of The Zonalwinds With The Equatorial Midnight Pressure Bulge In The Earth's Thermosphere: Empiricalevidence Of Momentum Balance, F. A. Herrero, H. G. Mayr, N. W. Spencer, A. E. Hedin, Bela G. Fejer

Bela G. Fejer

A minimum is observed at midnight in the time variation of averaged zonal winds measured in-situ near the equator at an average altitude of about 350 km, and we inquire whether observations of the equatorial midnight pressure bulge are consistent with this feature. The observed zonal wind maintains an eastward direction all night. It increases steadily in the early evening reaching a maximum of about 160 m/s at 2100 hrs local time (LT), dropping to a minimum of about 70 m/s around 2400 LT, then up to about 120 m/s around 0300 LT, decreasing thereafter and turning westward in the …

Studies Of Silicon-Phosphorus Bonding, Kenneth J. Dykema, Thanh N. Truong, Mark S. Gordon

Mark S. Gordon

Ab initio calculations are presented for several species containing a silicon-phosphorus bond. The types of bonding studied include "normal" single, double, and triple bonds, as well as an ylide-like structure. The latter is found to be much less strongly bound than the carbon analogue, with a smaller stretching force constant than that in silylphosphine. The insertions of silylene into the phosphine bond and of phosphinosilylene into H2 are discussed, with the former being illustrated using localized molecular orbitals along the intrinsic reaction coordinate (IRC). Silylene to silene isomerizations in both the closed-shell singlet and the lowest triplet states of SiPH3 …

A Theoretical Study Of Fluorine Atom And Fluoride Ion Attack On Methane And Silane, Larry P. Davis, Larry W. Burggraf, Mark S. Gordon, Kim K. Baldridge

Mark S. Gordon

We have performed MNDO and ab initio calculations for reactions of fluorine atom attack on methane and silane and, in addition, fluoride ion attack on the same molecules in the case of MNDO. We modeled both substitution and abstraction reactions in each case. Results were compared with experimental data, where available. Comparisons show that MNDO usually does as well as the ab initio methods in reproducing experimental values for D.E's of these reactions, but MNDO predicts activation barriers too high in most cases. Nevertheless, MNDO does qualitatively agree with the ab initio result that, while carbon undergoes abstraction much more …

Behavior Of An Electron In Helium Gas, John Bartholomew, Randall W. Hall, Bruce J. Berne

Randall W. Hall

N-Color Spin Models In The Large N Limit, Mehran Kardar, Miron Kaufman

Miron Kaufman

N color spin models are introduced and examined in the large N limit. The free energy and critical properties at the phase transition are studied. With relevant couplings between colors the transition becomes either first order or Fisher renormalized. With irrelevant couplings there is a crossover to first-order transitions through a nonclassical tricritical point. Connections are established between the N-color model, compressible systems, and systems with random impurities.

The Intrinsic Reaction Coordinate And The Rotational Barrier In Silaethylene, Michael W. Schmidt, Mark S. Gordon, Michel Dupuis

Mark S. Gordon

The intrinsic reaction coordinate (IRC) is a minimum-energy pathway connecting reactants to products via the transition state. An improved algorithm for the determination of an IRC is presented. The method is illustrated for the rotation of the silicon-carbon double bond in silaethylene. This IRC shows all coordinates vary smoothly during the rotation from the planar to twisted structures, except for a slight pyramidalization at carbon. The rotational barrier is found to be about 37 kcaljmol, in good agreement with experimental estimates.

Glass Formation And High Conductivity In The Ternary System Silver Iodide + Silver Arsenate (Ag3aso4) + Silver Metaphosphate (Agpo3): Host To Glassy .Alpha.-Silver Iodide?, Steve W. Martin, Alberto Schiraldi

Steve W. Martin

Wide regions of glass formation have been found in the ternary system xAgI + yAg,As04 + (1 - x - y)AgPO,. Glasses containing up to 75 mol 7% AgI can be formed in sections greater than 2 cm thick without signs of devitrification. Glass transition temperatures as high as 175 OC for glasses containing - 10 mol % AgI fall to -45 OC at the highest AgI content. An equivalent ratio of Ag1:N is defined and it is found that, for all glass-forming compositions, the electrical data as expressed in the Arrhenius form, u = A exp(-E,,/RT), log (./(a cm)-’), …

Determining The Temperature-Dependent Characteristic Temperature Of Beryllium From Electrical Resistance Measurements, Thomas W. Listerman, Xiao-Li Zhou

Thomas Listerman

We have developed an intermediate-level laboratory experiment to determine the temperature- dependent characteristic temperature of beryllium. The apparatus used to measure the resistance of a beryllium wire sample between liquid nitrogen and room temperatures was simple. The characteristic temperatures obtained from these data using the Block-Grüneisen model are in reasonable agreement with literature values obtained from resistivity and heat capacity experiments. The experiment introduced students to cryogenic and computer data analysis techniques and forced them to extend their knowledge of the theory of electrical resistance and of characteristic temperatures.

Electronic Structure Of The Phosphoryl And Thiophosphoryl Bonds, Michael W. Schmidt, Mark S. Gordon

Mark S. Gordon

.The pho~phoryl bond is presented as a. resonan~e hybrid between singly and triply bound structures. The types of electromcally excited states and a number of their potential surfaces can be understood within the confines of a singly bound model: However, a detailed analysis of the electronic distribution within the ground state shows significant contribution from the tnpl~ bound structure. In fact, increasing the electronegativity of the ligands at phosphorus increases the contribution of t~e tnp~y bound structure, so that the. PO bond order approaches that of a double bond. The thiophosphoryl bond may be VIewed m much the same manner …

Molecular And Electronic Structures Of Metallaspiropentanes, Mark S. Gordon, Philip Boudjouk

Mark S. Gordon

Recent efforts in this laboratory have concentrated on synthesizing metallaspiropentane compounds (I) with M = C, Si, Ge, Sn, Ni, and Zn. To date, the molecule with M = Si and R = methyl has been successfully prepared, 1 while attempts to synthesize the corresponding carbon compound have not reached fruition. This paper presents initial ab initio calculations on the species with M = C and Si and with R = H. Geometries for all species were calculated with the

Uses And Abuses Of Wastewater Injection Wells In Hawaii, F. L. Peterson, June Ann Oberdorfer

June Ann Oberdorfer

During the past two decades in Hawaii, more than 500 injection wells for the disposal of domestic sewage wastewater have been constructed and operated. Thus far, contamination of potable groundwater supplies has not been a problem. Many of the injection wells, however, have not performed as designed, and aquifer clogging and reduced injection capacity have produced numerous well failures resulting in public health, legal, and financial problems. Factors most commonly responsible for the well problems have been unfavorable hydrogeology, underdesign of injection well capacity, poor effluent quality, and lack of injection well maintenance. Detailed study of clogging mechanisms in the …

Random-Field Critical Behavior And The Ginzburg Criterion, Miron Kaufman, Mehran Kardar

Miron Kaufman

The Ginzburg criterion for crossover from classical to nonclassical critical behavior is derived in the presence of random fields. Experiments on dilute antiferromagnets in a field are examined, and the possibility of such a crossover is investigated. We also point out that the (necessarily) symmetric logarithmic divergence observed in birefringence measurements can be accompanied by a discontinuity, and a fitting form which allows for this and other corrections to scaling is proposed.

Predictors Of Grades In General Chemistry For Allied Health Students, Chris Craney, R. Armstrong

Chris L. Craney

Study searching for an effective predictor of student performance in the first term of a full-year general chemistry sequence for allied health students.

Electrochemical Reduction Of 1,1,4,4-Tetraphenylbutatriene In Dimethylformamid, Dennis Peters, Mark Anderson, Tsu-Yu Chen

Mark R. Anderson

No abstract is currently available.

Global Existence Theorems For Solutions Of Nonlinear Differential Equations With Prescribed Asymptotic Behavior, William Trench, T. Kusano

William F. Trench

No abstract provided.

Photothermal Lens Aberration Effects In Two Laser Thermal Lens Spectrometry, Stephen E. Bialkowski

Stephen E. Bialkowski

A comparison of theories describing two laser photothermal lens signals is given. The aberrant nature of this lens is accounted for in a theory which treats the propagation of a monitor laser in terms of a phase shift in this laser beam wave front. The difference between theories are discussed in terms of the predicted signal strengths and temporal behavior. The aberrant theory results in smaller theoretical signal strengths and different functional relationships between signal and analyte level.

Theory Of Spectral Asymmetries And Nonlinear Currentsin The Equatorial Electrojet, E. Kudeki, D. T. Farley, Bela G. Fejer

Bela G. Fejer

The spectral up-down asymmetry of type 1 echoes returned from the equatorial electrojet irregularities is shown to be a consequence of the nonlinear development of the horizontally propagating large scale primary waves which dominate the k spectrum of the electrojet turbulence. The waves reduce the vertical electric polarization field of the electrojet and suffer second harmonic distortion as they grow. These effects together could cause an asymmetry exceeding 20% between the upward and downward components of the relative (to the ions) electron velocity associated with the primary waves. This asymmetry, which changes its direction from day to night as does …

Symmetry Behavior Of The Static Taub Universe: Effect Of Curvature Anisotropy, T. C. Shen, B. L. Hu, D. J. O'Connor

T. -C. Shen

Using the static Taub universe as an example, we study the effect of curvature anisotropy on symmetry breaking of self-interacting scalar field. The one-loop effective potential of a λφ⁴ field with arbitrary coupling (ξ) is computed by ζ-function regularization. It is expressed as a perturbative series in a small anisotropy parameter α measuring the deformation from the spherical Einstein universe with radius of curvature α. This result is used for analyzing the symmetry behavior of such a system as a function of the geometric (α,α) and field (ξ,λ) parameters. The result is also used to address the question of …

Gravitational Twins Revisited, Br Holstein

Barry R Holstein

No abstract provided.

Possible Weak Interaction Experiments With Polarized He-3, Br Holstein

Barry R Holstein

No abstract provided.