Thesis (Ph. D.)--Florida State University, 2006. / Advisors: Vasken Hagopian, Sharon Hagopian, Florida State University, College of Arts and Sciences, Dept. of Physics. Title and description from dissertation home page (viewed Sept. 15, 2005). Document formatted into pages; contains xiv, 155 pages. Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, December 2000. / Includes bibliographical references. Also available on the Internet.

Thesis (M.S.)--Baylor University, 2006. / Includes bibliographical references (p. 62-67).

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The differential and total inelastic cross sections for electron-mercury atom collisions were calculated using the Born approximation together with the Ochkur approximation for the transitions (^1S_0 -> ^3P_0), (^1S_0 -> ^3P_2), (^3P_0 -> ^1S_0), and (^3P_2 -> ^1S_0) at one eV energy intervals from 1 eV - 33 eV above threshold. A reprint of work previously published containing values for polarizabilities of all the atoms is contained in Appendix B.

The quantum mechanical theory of rotational and vibrational transitions in atom-diatom systems is investigated and summarized. The time independent scattering formalism of Arthurs and Dalgarno is used, and the degeneracy-averaged cross section is expressed in terms of the scattering S matrix. The major emphasis is on the solution of the rotationally strongly coupled differential equations. Various methods of solving the scattering equations are examined and some of the inadequacies of these methods are discussed. A strong coupling (SC) approximation, valid for small energy exchange, is introduced and tested numerically on some model problems. A first-order iteration to the SC approximation is presented to improve the SC approximation and to extend the range of validity to cases of larger energy exchange. The SC results are compared with the accurate numerical solution and other approximate methods for some model problems. The comparison clearly demonstrates that the SC approximation is the computationally fastest, reasonably reliable method known for computing rotationally inelastic cross sections.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 1975 / Vita. / Includes bibliographical references. / Ph. D. / Ph. D. Massachusetts Institute of Technology, Department of Physics

The objective of this thesis is to describe the development, construction and use of a new tool for optical coherent transient spectroscopy. The new tool is a frequency-switched CO₂ laser. A highly stable laser design was modified to include an intra cavity electro-optic modulator, which al lows the output of the laser to be frequency-switched. The frequency modulated output is used in spectroscopic experiments whose goals are the determination of decay rates for infrared moIecuIar transitions. The use of a frequency-switched laser is the most prom i sing means of making such measurements on nonpoIar molecules. The use of an electro-optic crystal inside a laser cavity introduces a number of fundamental problems which must be overcome before the instrument can be used to make useful spectroscopic measurements. These problems are brought about by the need for a stable laser amplitude and frequency output. The development of a novel stabilization technique to overcome these problems is documented in this thesis. Also included in this thesis is a description of the microcomputer and associated electronics necessary to integrate the laser into an experimental apparatus capable of performing signal averaging and background subtraction on raw time resolved data. The final chapters of this work describe experiments and results of measurements of the scattering cross sect ions of a nonpolar molecule with rare gas perturbers. The nonpolar molecule is SF₆ and the rare gas collision partners are Helium, Argon, and Xenon. The results indicate that the scattering cross section for state changing collisions displays a mass dependance predicted by classical collision theory. However, the measured cross sections for elastic velocity-changing collisions appears to be mass independent, which is at variance with theory.