Digital Commons Network^™

Electron-Ion Recombination In Gas Mixtures Of Helium, Nitrogen, And Carbon Dioxide, Ian M. Littlewood, M. C. Cornell, Kaare J. Nygaard

Physics Faculty Research & Creative Works

A study has been conducted to determine the electron-ion recombination rates in gas mixtures of helium, nitrogen, and carbon dioxide. Measurements were made as functions of electric field strength, gas pressure, and gas composition. In gas mixtures containing only nitrogen and carbon dioxide, the rates were dependent on pressure. This dependence is interpreted as being due to the separate effects of two- and three-body recombination processes. No pressure dependence was observed for mixtures containing helium. In such mixtures, two-body recombination appears to be dominant. Moreover, the addition of relatively low concentrations of helium to the discharge leads to a dramatic …

Resonant Electron Transfer And Excitation In Two-, Three-, And Four- Electron Caq +20 And Vq +23 Ions Colliding With Helium, J. A. Tanis, E. M. Bernstein, W. G. Graham, M. P. Stockli, M. Clark, Robert H. Mcfarland, T. J. Morgan, K. H. Berkner, A. S. Schlachter, J. W. Stearns

Physics Faculty Research & Creative Works

Significant new evidence is reported for resonant transfer and excitation in ion-atom collisions. This process, which is analogous to dielectronic recombination, occurs when a target electron is captured simultaneously with the excitation of the projectile followed by photon emission. Strong resonant behavior with structure, in agreement with theoretical calculations, is observed in the cross section for projectile K x rays coincident with single electron capture for 100-360-MeV Ca16+,17+,18+20 and 180-460-MeV V19+,20+,21+23 ions colliding with helium. © 1984 The American Physical Society.

Dipole Moment And Potential Energy Functions Of The X ¹Σ + And A 1Σ+ States Of Nah, W. T. Zemke, Ronald E. Olson, K. K. Verma, W. C. Stwalley, B. Liu

Physics Faculty Research & Creative Works

Calculated radiative transition probabilities between all vibrational levels in the X 1Σ+ state (υ=0-21) and in the A 1Σ+ state (υ=0-32) of NaH are given. In addition, the calculated spontaneous emission lifetimes for vibrational- rotational levels (J=0,1) and the calculated dipole moments for these same levels are given. The calculations use new hybrid potential energy curves based on Rydberg-Klein-Rees (RKR) and ab initio potential curves. The RKR curve for the X state is new. The calculations use new ab initio dipole moment functions of internuclear distance. © 1984 American Institute of Physics.

A Three-Spin Interaction Model, Harry A. Brown

Physics Faculty Research & Creative Works

A three-spin interaction in the form of a box product, σ1 x σ2 · σ3, is considered. The thermodynamic behavior is investigated using an effective field theory. A second-order phase transition is found and the magnetization and energy per spin appear to be very similar to those of an ordinary Heisenberg ferromagnet. © 1984.

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

Physics Faculty Research & Creative Works

The homogeneous nucleation rate of n-nonane has been measured as a function of temperature and supersaturation ratio in a precision fast-expansion chamber. The measured nucleation rate ranges from 102 to 105 drops/cm3 over the temperature range 215-270 K. The results have been compared to the classical theory and to the classical theory with the RKC replacement factor. The RKC theory functional form is the basis for an empirical rate equation to fit the data. A full listing of the thermodynamic constants used for the reduction of the data is given. © 1984 American Institute of Physics.

The Effects On Plant Growth, W M. Porter, J. S. Yeates

Journal of the Department of Agriculture, Western Australia, Series 4

The level of acidity of a soil reflects its chemical and sometimes its biological condition. Changes in acidity mean changes in the availability to plants of some soil elements, and modifications to the biological processes in the soil.

Some elements become more available to plants in acis soils, and in some soils particular elements can reach toxic levels. Other elements can be effected in the opposite way: deficiencies can develop in acid conditions.

It is important to realise, however, that the chemical nature of all soils varies. Beccause of these variations, acidity can affect each soil differently and thus influence …

Molecular-State Cross-Section Calculations For H+Csh-+Cs+, Ronald E. Olson, M. Kimura, H. Sato

Physics Faculty Research & Creative Works

Pseudopotential molecular-structure calculations have been used to obtain the seven lowest 1 and 1 states of CsH. These states and their associated radial and rotational coupling terms have been used to calculate the cross sections for H-+Cs+ ion-pair production in H+Cs(6s) and H+Cs*(6p) collisions at energies from 0.1 to 10 keV. The ion-ion mutual neutralization cross section, H-+Cs+ H+Cs, is also presented. The cross-section calculations were done with the perturbed-stationary-state method, modified to include two-electron translation factors. The ion-pair production cross section for ground-state reactants is in good agreement with experiment; collisions of H with excited Cs*(6p) show an order-of-magnitude …

Systematic Estimate Of Binding Energies Of Weakly Bound Diatomic Molecules, Linda L. Vahala, Mark D. Havey

Electrical & Computer Engineering Faculty Publications

There is often insufficient spectroscopic data for a full RKR inversion to yield a potential for weakly bound diatomic molecules. In these cases, parametrized functions such as the Morse or Thakkar potentials may be used to obtain estimates of the binding energy. The Thakkar potential is more flexible, and has been used successfully on some weakly bound systems. In the more usual case, the Thakkar parameter p, which determines long range behavior R^-p, is chosen by p=-a₁-1, where a₁ is the first Dunham coefficient; p is usually noninteger. The authors present …

Biomineralizationof Fe3O4 In Bacteria, R. B. Frankel, G. C. Papaefthymiou

Physics

No abstract provided.

The Special Theory Of Relativity In A Gravitational Field, Masayuki Note

Masters Theses

"A theory is presented which generalizes the special theory of relativity to an acceleration field. The theory is based on the re-interpretation of linear motion as an acceleration field and is applied to a gravitational field. It is shown that the theory explains the precession of Mercury's perihelion and the deflection of light near the sun"-- Abstract, p. iv

Additional Remarks To The Schrödinger Spin‐Exchange Ferromagnet, Harry A. Brown

Physics Faculty Research & Creative Works

No abstract provided.

Non-Linear Oscillation, Automodulation And Anelasticity, Tetsuro Suzuki, Manfred Wuttig

Physics Faculty Research & Creative Works

The auto modulation observed in the course of internal friction is discussed as a special example of the universal nature of non-linear oscillations. Universal features of non-linear oscillations are the requirement of energy supply or negative damping and the period doubling route to chaos. The negative damping responsible for the auto modulation is described in terms of the soliton model for twinning deformation. © 1984 The Japan Society of Applied Physics.

Underwater Acoustic Wavefront Phase Fluctuations, George L. Vojtech Jr.

OES Theses and Dissertations

In conventional underwater acoustics sound propagation is generally modeled and applied as a coherent or incoherent process. This paper addresses a relatively new theory, that of a range driven increasingly incoherent ray propagation through a real ocean environment, Possible mechanisms are discussed and experimental data presented to reinforce the theory.

Radiation Damage To Gaas Solar Cells Including Isotropic Effects, Larry Victor Stock

Physics Theses & Dissertations

A model is developed for the short circuit current of a GaAs solar cell due to radiation (proton or electron) induced defects in the crystal structure. This model is verified by a comparison with proton and electron irradiation results. For electron radiation and energetic protons (energy> 10 MeV), it is found that the damage in the crystal is independent of the angle of incidence. On the other hand, for lower energy proton radiation, the damage as a function of cell thickness is highly dependent on incident angle and energy. The cell's response to low energy protons is strongly dependent on …

Multiple Ionization Of Rare Gases By H+ And He+ Impact, R. D. Dubois, L. H. Toburen, M. Eugene Rudd

M. Eugene Rudd Publications

Absolute cross sections for multiple ionization (σ_q)of He, Ne, Ar, and Kr are presented for proton-impact energies between 10 and 4000 keV. Charge states up to 6 + are observed for Kr. The results are obtained by measuring relative yields of multiply charged ions with a time-of-flight spectrometer and normalizing to total ion-production cross sections σ_T= ∑qσ_q. The results are compared with existing proton- and electron-impact data. Relative multiple- to single-ionization cross-section ratios are also presented for He⁺ impact.

The Feasibility Of The X-Ray Laser Pumped With A Nuclear Explosion, David W. Hafemeister

Physics

Recent reports have indicated that an x-ray laser pumped with a nuclear explosion at a wavelength of 1.4nm (0.9 keV) has made some initial progress. It has been proposed to extend the development of this device to establish it as part of a layered ballistic missile defensive system to protect the United States against a nuclear attack. This paper will discuss the following aspects on the feasibility of this system: (1) Conditions affecting the efficiency of the X-ray laser; (2) Angular resolution and size of.the laser rods; (3) Energy on targets; (4) Basing Modes; (5) Countermeasures; and (6) Legal constraints.

Using Prisms To Excite Leaky Waves Or To Launch Surface Electromagnetic Waves, Gerald Kent Sirotiak

Doctoral Dissertations

"The ability of prisms to couple incident VEM radiation from a laser beam into leaky waves or to launch surface electromagnetic waves has been investigated. We have set out to discover wheth~r or not a single prism placed above an air-metal interface can be used to couple light from a laser beam into leaky electromagnetic waves. We have then attempted to relate the single prism technique to tb.e double prism technique for launching surface waves. We have also compared the coupling into a single interface to that into a waveguide.

We have found that prisms are unable to couple incident …

Angular Differential Cross Sections For The Excitation Of 1¹S Helium To The 2¹S And 2¹P States By 25- To 100-Kev Proton Impact, Thomas Jay Kvale

Doctoral Dissertations

"Angular differential cross sections for the proton impact excitation of ground state helium (1¹S) to the 2¹S and 2¹P states have been measured for the first time in the energy range 25- to 100-keV using the energy-loss technique. The present data have been numerically summed over the 2¹Sand 2¹P states to produce differential cross sections for excitation to the composite n=2 state and are in excellent agreement with previous experimental measurements of that process. Total cross sections have been obtained by numerically integrating the present data over scattering angle. and …

Pseudo-Brewster And Second-Brewster Angles Of An Absorbing Substrate Coated By A Transparent Thin Film, R. M.A. Azzam, T F. Thonn

Electrical Engineering Faculty Publications

The pseudo-Brewster angle of minimum reflectance for the p polarization, the corresponding angle for thes polarization, and the second-Brewster angle of minimum ratio of the p and s reflectances are all determined as functions of the thickness of a transparent film coating an absorbing substrate by numerical solution of the exact equations that govern such angles of the form Re(Z′/Z) = 0, where Z = R_p, R_s, or ρ represent the complex amplitude-reflection coefficients for the p and s polarizations and their ratio (ρ =R_p/R_s), …

Mst Radar Data-Base Management, Vincent B. Wickwar

All Physics Faculty Publications

No abstract provided.

Isotope Effect And Momentum-Transfer Scaling In The Elastic-Scattering Differential Cross Sections For Hydrogen-Isotope Collision Systems, Eduard P. Rille, Jerry Peacher, Denver G. Seely, Thomas J. Kvale, E. Redd, D. M. Blankenship, John T. Park

Physics Faculty Research & Creative Works

A projectile-dependent isotope effect was found for the elastic-scattering differential cross sections in the hydrogen-isotope collision systems. All four differential cross sections lie on a common curve if they are divided by the square of the reduced mass and plotted against momentum transfer. The experimental results are in satisfactory agreement with a simple Glauber-approximation calculation.

Electron Capture Cross Sections For Tih⁴⁺, H. Sato, M. Kimura, A. E. Wetmore, Ronald E. Olson

Physics Faculty Research & Creative Works

Electron capture cross sections have been computed for Ti⁴⁺+H to Ti³⁺+H+ and Ti³⁺+H+ to Ti⁴⁺+H, where the reactants were in their ground states. The energy range investigated was 0.1 to 10 keV amu-1. The impact parameter perturbed-stationary-state method incorporating electron translation factors were used to calculate the cross sections. The molecular wavefunctions were generated using the pseudo-potential method. At 1 keV amu-1 ( nu rel=4.4*107 cm s-1), representative electron capture cross sections for the Ti⁴⁺+H and Ti³⁺+H⁺ reactions are 2*10-15 cm 2 and 1*10-17 cm2, respectively. An …

Two- And Three-Body Electron-Ion Recombination In Carbon Dioxide, Ian M. Littlewood, M. C. Cornell, B. K. Clark, Kaare J. Nygaard

Physics Faculty Research & Creative Works

The electron-ion recombination rate in carbon dioxide was measured as a function of electric field strength and gas pressure. The separate effects of two- and three-body recombination was observed, and the respective rate constants obtained. The results indicate that three-body recombination is dominant at low field strengths for gas pressures above 1 atm, whereas two-body recombination is dominant at high field strengths.

Reactive Scattering Cell For Atomic Hydrogen And Deuterium, John T. Park, E. Redd, T. J. Kvale, E. Rille

Physics Faculty Research & Creative Works

A design for a high-temperature reactive scattering cell for atomic hydrogen and atomic deuterium is described. At approximately 2700 K a dissociation of the molecular target species of over 95% has been obtained. The lifetime of 340 h of operation is sufficient for precision, long-time, differential cross-section measurements.

Charge Transfer And Ionisation Processes Involving Multiply Charged Ions In Collision With Atomic Hydrogen, D. J.W. Hardie, Ronald E. Olson

Physics Faculty Research & Creative Works

Total cross sections are presented for the charge transfer reaction X^q++H(1s) to X(q-1)+H⁺ and ionization process X^q++H(1s) to X^q++H⁺-e-. Here X^q+ is a fully or partially stripped ion. The collision energy range lies between 25-200 keV amu-1. Cross sections are also given for charge transfer into particular ionic n states and n, l states for energies of 25 and 50 keV amu-1, where X^q+=H⁺, He 2+, C⁶⁺, O⁸⁺. The calculations were performed by the classical trajectory Monte Carlo method of Olson and …

Low-Mass Solitons From Fractional Charges In Quantum Chromodynamics, A. P. Balachandran, V. Parameswaran Nair, N. Panchapakesan, S. G. Rajeev

Publications and Research

Slansky, Goldman, and Shaw have proposed a model to account for the observation of fractionally charged states. We show that in this model, there are expected to be several low-mass solitons (four being in the mass range ∼20-60 MeV) associated with the third homotopy group π₃(SU(3)/SO(3))=Z₄, besides a low-mass (∼30 MeV) Z₂ monopole. Confirmation of these levels and hence of the model has important implications for Cabrera's results on the magnetic monopole. An efficient algorithm for the calculation of π3(G/H) for a general Lie group G and a subgroup H is developed. It is pointed …

Electron Drift Velocities In Gas Mixtures Of He, N2, And Co 2, Michael C. Cornell, Ian M. Littlewood, Howard L. Brooks, Kaare J. Nygaard

Physics Faculty Research & Creative Works

An electron swarm experiment has been used to obtain electron drift velocities in the He:CO2:N2 mixtures 0:1:1, 3:1:2, and 3:1:1. The E/N range of 3 to 57 Td was studied with total gas pressure varied from 50 to 200 Torr. These particular mixtures have not been previously studied experimentally. Good agreement is observed between theoretical calculations and experimental data.

Cross Sections For Ionizaton Of Gases By 5-4000-Kev Protons And For Electron Capture By 5-150-Kev Protons, M. Eugene Rudd, R. D. Dubois, L. H. Toburen, C. A. Ratcliffe, T. V. Goffe

M. Eugene Rudd Publications

Using the parallel-plate-capacitor method and a capacitance manometer to determine pressures, total cross sections for the production of positive and negative charges were measured for 5-4000- keV-proton impact on He, Ne, Ar, Kr, Hz, N₂, CO, 0₂, CH₄, and C0₂. From these, ionization and electron-capture cross sections were obtained and fitted to semi-empirical equations describing the energy dependence in terms of a few parameters. At high energies very good agreement is obtained in the comparison of the ionization cross sections to earlier proton- and electron-impact measurements and with theoretical treatments where they …

Non-Equilibrium L-Shell Effects On K-Shell X Rays For 20-54 Mev S+C Collisions, Donald Solon Shippy

Masters Theses

Projectile K x-ray yields have been measured as a function of target thickness (2.0-150 μg/ cm²⁾ for 20-54 MeV S^q+ ions incident on this carbon foils using the WMU EN tandem Van de Graaff accelerator. The measured K x-ray yields were fond to increase for thicknesses < 15 μg/cm² and decease for thicknesses > 15 μg/cm² . The increasing yield is attributed to L-Shell non-equilibrium as the ion traverses the foil, while the decreasing yield is attributed to K-shell non-equilibrium. Analysis of the data was performed by modifying the "two-component" model of Betz et al. to include the effect of …

Magnetic Phase Transition, Aggregate Formation, And Electrical Conductivity In Fecl3-Doped Polyacetylene, E. K. Sichel, M. F. Rubner, J. Georger, Jr., G. C. Papaefthymiou, S. Offer, Richard B. Frankel

Physics

Both Fe³⁺ and Fe²⁺ ions occur in FeCl₃-doped polyacetylene. At low dopant levels (2+ and Fe³⁺ ions are paramagnetic down to 4.2 K. At dopant levels >0.01 mole fraction, there is evidence from Mössbauer spectroscopy that Fe²⁺ ions associate into aggregates which are magnetically ordered below 25 K. Aggregate formation appears to correlate with high electrical conductivity.