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Typescript. Includes vita and abstract. Includes bibliographical references (leaves 273-280) Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

The response of a polyatomic gas to microwave radiation including both steady state (pressure broadening) and time dependent (coherence transients) effects - is described theoretically. The treatment is based on solutions of a quantum mechanical Boltzmahn equation and employs kinetic theory methods which have previously been used in the explanation of the field dependence of transport phenomena (Senftleben-Beenakker effects). Much of the recent theoretical work of pressure broadening and coherence transient phenomena is based on a two (energy) state model for the gas molecules. This model, when developed from a density operator point of view, results in a coupled set of three equations which are mathematically equivalent to the Bloch equations of NMR. The present work reexamines this description, and replaces it with a two level model for the gas system. Here, the term "level" implies explicit consideration of the rotational (magnetic) degeneracy associated with each energy state. This model gives a more appropriate representation of the interaction of microwave radiation with a real molecular system. In particular, a more complete set of coupled equations result from this description and involve quantities in addition to the three moments used in a two state approach. The most important of these latter effects are represented by spherical harmonics Ƴ(q) (J) in he angular momentum J of the relevant energy levels. An analogous treatment of rotational effects has previously been used in Senftleben-Beenakker studies. Specific molecular types of interest in microwave spectroscopy -diamagnetic diatonics and linear polyatomics, symmetric tops, and inverting symmetric tops - are treated separately by this two level approach. The vector (and tensor) nature of the motions are emphasized throughout. The number of rotational polarizations that arise in the general two level case is often quite large. The simplest example of a two level system is the j=0 to j=l transition of a diamagnetic diatomic. This is studied in some detail. Here, the scalar component Ƴ⁽²⁾⁰(J) is the only rotational polarization affected by linearly polarized radiation in the usual experiments. The effect of this quantity on both steady state and transient phenomena is described, and a new "combination" experiment is suggested as the best way to detect the presence of this additional polarization. The Doppler effect is treated by appropriately including the effects of translational motion in the quantum Boltzmann equation. A more general set of coupled moment equations then results, and the manner in which the macroscopic velocity polarizations arise is thereby established. A model method solution of the quantum Boltzmann equation, emphasizing the parity invariance of the collision super-operator, is given for a steady state absorption experiment in the absence of saturation but including Doppler effects. Throughout this thesis, the relaxation rates, are related to kinetic theory collision cross sections by solving the quantum Boltzmann equation. Extensive use is made of rotational invariance to reduce the number of independent collision integrals, and their approximate evaluation is accomplished within the context of the distorted wave Born approximation. All collision integrals for the pure internal state polarizations are found to-be expressible in terms of one translational factor, which is itself further approximated by a modified Born approximation. Correspondingly, the translational factor which arises in the relaxation of macroscopic velocity polarizations is completely specified by relating it to the Ω(ℓ,s) integrals of traditional kinetic theory. / Science, Faculty of / Chemistry, Department of / Graduate

Transformational change for Broadening Participation in Engineering (BPE) of racial, ethnic, and gender groups has not occurred, despite continuing efforts for over four decades. BPE can be represented through particular activities to increase underrepresented students' participation at the undergraduate and graduate levels (herein referred to as BPE Work). One approach to investigating the complexity of change through BPE is through the analysis of a sub-group of faculty who engage in BPE Work within the system of engineering education. In the case of BPE, investigation of faculty engagement is limited. Further, limited exploration of the majority group's experiences (i.e., white men) exists concerning their agency and this type of work. This study investigates the experiences of engineering faculty who identify as white men and have been engaged in BPE Work using faculty agency and narrative. These narratives reveal insights into the current system that may drive, sustain, or prohibit BPE change. Using the narrative experiences of eight engineering faculty involved in BPE Work who identify as white men, this research explores the following questions: (1) What activities do white men faculty describe in their personal narratives of engaging in BPE Work; (2) How do white men faculty describe their trajectory into and through engaging in BPE Work; (3) What factors influence the actions and perspectives of white men faculty engaged in BPE Work; and (4) How do white men faculty describe the outcomes to their professional and personal lives when using their agency for BPE Work? Application of data analysis to research questions to elicit findings found in chapter 4 consisted of an accountability cycle, BPE Work activities, factors that impact (constraining or enabling) BPE Work, and outcomes to the participants' lives from engagement in BPE Work. The participants of this study shared experiences in which they expressed perspectives on BPE, reflecting on their backgrounds. Archer (2003) describes the ability to take a stance regarding society as invoking an "active agent," but that this stance is not a one-and-done situation (p. 343). This study resulted in findings for Deans and Provosts on the vital need for a normalized climate for BPE Work, the hidden essential functions of Engineering Student Support Centers, value-focused needs for tenure/promotion/merit processes for BPE Work, the trajectory of faculty development in BPE Work, the experiences that permeate into faculty life in undergraduate student development, and the need for future work in interrogating power dynamics in engineering education The need for all faculty to be involved in change alludes to a necessary understanding. The number of faculty of color and women faculty is not robust enough or supported to carry the system's burden. A need is present to take a realistic look at how white men experience BPE Work. This look is vital for policy and the identification of system constraints that need to be evaluated and used to drive BPE forward. / Doctor of Philosophy / Change for Broadening Participation in Engineering (BPE) (specifically for underrepresented races, ethnicities, and women in engineering) has not occurred, despite continuing efforts for over four decades. BPE can be represented through particular activities to increase underrepresented students' participation at the undergraduate and graduate levels (herein referred to as BPE Work). One approach to investigating the complexity of change through BPE is through the analysis of a sub-group of faculty who engage in BPE Work within the system of engineering education. In the case of BPE, investigation of faculty engagement is limited. Further, limited exploration of the majority group's experiences (i.e., white men) exists concerning their agency and this type of work. This study investigates the experiences of engineering faculty who identify as white men and have been engaged in BPE Work using faculty agency and narrative. These narratives reveal insights into the current system that may drive, sustain, or prohibit BPE change. Using the narrative experiences of eight engineering faculty involved in BPE Work who identify as white men, this research explores the following questions: (1) What activities do white men faculty describe in their personal narratives of engaging in BPE Work; (2) How do white men faculty describe their trajectory into and through engaging in BPE Work; (3) What factors influence the actions and perspectives of white men faculty engaged in BPE Work; and (4) How do white men faculty describe the outcomes to their professional and personal lives when using their agency for BPE Work? Using narrative methods, this study resulting in findings at the departmental, college, and national levels that imply the need for further investigation into the experiences of white faculty in engineering and their involvement in BPE Work. The need for all faculty to be involved in change alludes to a necessary understanding. The number of faculty of color and women faculty is not robust enough or supported to carry the system's burden. A need is present to take a realistic look at how white men experience BPE Work. This look is vital for policy and the identification of system constraints that need to be evaluated and used to drive BPE forward.

No description available.

White dwarfs are particularly interesting due to their broad application to the field of astronomy (cosmochronology, SN Ia progenitors, asteroseismology). Examining distributions of white dwarf masses and temperatures, it is evident that there is some flaw in our ability to make physical atmosphere models. Tremblay and Bergeron (2009) used an {\it ad hoc} treatment of line broadening and derived significantly different surface gravity and temperatures for white dwarfs, demonstrating the importance of the line broadneing treatment in determining stellar parameters for high surface gravity stars. This thesis presents a new line broadening program, Xenomorph, based on simulation techniques. Xenomorph is used to examine various approximations used in line broadening calculations used in white dwarf atmospheres. Some approximations, like including fine structure and lower state perturbations, have small, if detectable effects. Ion motions during a transition can make features commonly seen in Stark profiles less pronounced and leads to an increase in the FWHM of the lines. Including a more complete basis set at higher densities will result in extra features, including asymmetries that has been observed in many experiments. / text

No description available.

A complete stochastic theory of relaxation is developed in terms of a homogeneous equation for the averaged density matrix of a system immersed in a thermal bath. This theory is then used as the basis of a new stochastic approach to the phenomenon of collisional broadening of spectral line shapes. Single photon and multiphoton processes are studied. The features of a line shape are linked by simple expressions to the statistical properties of a stochastic hermitian Hamiltonian. The ordinary line shape predicted by Kubo's approach is generalized. The present approach predicts broadening as well as asymmetry and shift. A representation of line shapes in multiphoton processes by diagrams is also developed.

No description available.

The object of this thesis is to extend the current tables for two useful quantities when calculatingcollisional broadening, the cross-section of interaction and the velocity parameter.These quantities, which have hitherto been tabulated for lower states, have now been calculatedfor higher lying states and are used in the ABO - model for spectral line broadening.Having larger tables for these values enables broadening calculations for more spectral linesand this thesis shows examples of calculations which beneted from this. During the calculationsof the tables some unexpected behaviour in the distribution of values arose whichhas not been seen previously. This could point to an unknown underlying mechanism.