Thesis (Ph. D.)--California Institute of Technology, 2000. UM #9972587. / Advisor names found in the Acknowledgments pages of the thesis. Title from home page. Viewed 02/08/10. Includes bibliographical references.

by Yu-san Cheung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references. / ABSTRACT --- p.ii / ACKNOWLEDGMENTS --- p.iv / EDITORIAL NOTE --- p.v / CONTENTS --- p.vi / LIST OF TABLES --- p.ix / LIST OF FIGURES --- p.xii / Chapter CHAPTER 1. --- INTRODUCTION / Chapter 1.1 --- Potential Energy Surfaces --- p.1 / Chapter 1.2 --- Ab initio Method --- p.1 / Chapter 1.2.1 --- Basis Sets --- p.2 / Chapter 1.2.2 --- Correlation Methods --- p.4 / Chapter 1.3 --- Locations and Characterizatioiis of Stationary Points --- p.5 / Chapter 1.4 --- Refinements of Energy and the Gaussian-2 Method --- p.7 / REFERENCES --- p.10 / Chapter CHAPTER 2. --- AN AB INITIO MOLECULAR ORBITAL STUDY OF THE GaH4 POTENTIAL ENERGY SURFACE / Chapter 2.1 --- Introduction --- p.12 / Chapter 2.2 --- Computational Details --- p.12 / Chapter 2.3 --- Results and Discussion --- p.13 / Chapter 2.3.1 --- Jahn-Teller Distortion from Td Symmetry --- p.18 / Chapter 2.3.2 --- Transition Structures Connecting Various Equilibrium Structures --- p.19 / Chapter 2.3.3 --- The Dissociation Products --- p.20 / Chapter 2.4 --- Conclusion --- p.21 / REFERENCES --- p.22 / Chapter CHAPTER 3. --- A GAUSSIAN-2 AB INITIO STUDY OF THE CH3S2 AND CH3S2+ POTENTIAL ENERGY SURFACES / Chapter 3.1 --- Introduction --- p.24 / Chapter 3.2 --- Computational Details --- p.25 / Chapter 3.3 --- Results and Discussion --- p.26 / Chapter 3.3.1 --- The Potential Energy Surface of CH3S2 Radicals --- p.26 / Chapter 3.3.2 --- The Potential Energy Surface of CH3S2+ Cations --- p.37 / Chapter 3.3.3 --- The Equilibrium Structures of CH3S2- Anions --- p.40 / Chapter 3.3.4 --- Interpretation of Experimental Results with Theoretical Predictions --- p.40 / Chapter 3.4 --- Conclusion --- p.42 / REFERENCES --- p.43 / Chapter CHAPTER 4. --- A GAUSSIAN-2 AB INITIO STUDY OF THE CH3O2 AND CH302+ POTENTIAL ENERGY SURFACES / Chapter 4.1 --- Introduction --- p.46 / Chapter 4.2 --- Computational Details --- p.47 / Chapter 4.3 --- Results and Discussions --- p.48 / Chapter 4.3.1 --- The Equilibrium Structures of CH3O2 Radicals --- p.48 / Chapter 4.3.2 --- The Transition Structures of CH3O2 Radicals --- p.59 / Chapter 4.3.3 --- The Equilibrium Structures of CH3O2+ Cations --- p.62 / Chapter 4.3.4 --- The Transition Structures of CH3O2+ Cations --- p.66 / Chapter 4.3.5 --- "The Equilibrium Structures of CH3O2"" Anions" --- p.68 / Chapter 4.3.6 --- Comparisons with Available Experimental Results --- p.69 / Chapter 4.4 --- Conclusion --- p.59 / REFERENCES --- p.72 / Chapter CHAPTER 5. --- MISCELLANEOUS / Chapter 5.1 --- "A Gaussian-2 ab initio Study of CH3SSCH2,CH3SF and Their Cations" --- p.74 / Chapter 5.2 --- A Gaussian-2 ab initio Study of SF5 and SF5+ --- p.80 / Chapter 5.3 --- "A Gaussian-2 ab initio Study of SFn+/SFn/SFn -(n = 1, 2, 3)" --- p.84 / REFERENCES --- p.91 / Chapter CHAPTER 6. --- CONCLUSION --- p.93 / REFERENCES --- p.94 / "APPENDIX A. PROCEDURES IN THE G2, G2(MP3) AND G2(MP2) METHODS" / Chapter A.l --- Location of Geometry --- p.95 / Chapter A.2 --- "Approximation of the QCISD(T)/6-311+G(3df,2p) Energy" --- p.95 / Chapter A.3 --- High-Level Correlation (HLC) Correction --- p.96 / Chapter A.4 --- Zero-Point Vibrational Energy (ZPVE) --- p.96 / APPENDIX B ENTHALPY CALCULATION --- p.97

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, August 1998. / Includes bibliographical references. Also available on the Internet.

No description available.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI Company.

Not available / text

Thesis (Ph.D.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [114]-119).

Protonated epoxides feature prominently in organic chemistry as reactive intermediates. Gas-phase calculations studying the structure and ring-opening energetics of protonated ethylene oxide, propylene oxide and 2-methyl-1,2-epoxypropane were performed at the B3LYP and MP2 levels (both with the 6-311++G** basis set). Structural analyses were performed for 10 protonated epoxides using B3LYP, MP2, and CCSD/6-311++G** calculations. Protonated 2-methyl-1,2-epoxypropane was the most problematic species studied, where relative to CCSD, B3LYP consistently overestimates the C2-O bond length. The difficulty for DFT methods in modeling the protonated isobutylene oxide is due to the weakness of this C2-O bond. Protonated epoxides featuring more symmetrical charge distribution and cyclic homologues featuring less ring strain are treated with greater accuracy by B3LYP. Ion-pair separation (IPS) of THF-solvated fluorenyl, diphenylmethyl, and trityl lithium was studied computationally. Minimum-energy equilibrium geometries of explicit mono, bis and tris-solvated contact ion pairs (CIPs) and tetrakis-sovlated solvent separated ion pair (SSIPs) were modeled at B3LYP/6-31G*. Associative transition structures linking the tris-solvated CIPs and tetrakis-solvated SIPs were also located. In vacuum, B3LYP/6-31G* ΔHIPS values are 6-8 kcal/mol less exothermic than the experimentally-determined values in THF solution. Incorporation of secondary solvation in the form of Onsager and PCM single-point calculations showed an increase in exothermicity of IPS. Application of a continuum solvation model (Onsager) during optimization at the B3LYP/6-31G* level of theory produced significant changes in the Cα-Li contact distances in the SSIPs. An increase in of ion pair separation exothermicity was observed upon using both PCM and Onsager solvation models, highlighting the importance of both explicit and implicit solvation in modeling of ion pair separation. / Ph. D.

The settling of spherical and cylindrical particles in a linearly stratified fluid is investigated using experiments. The double-tank method is used to generate a linear stratification with a red colored dye homogeneously mixed in the heavy water tank. As a result of feeding the stratification using dyed heavy water, the concentration of dye varies with depth in the experiment tank. A powerful back-light and a digital camera are used to record the events. Assuming the concentration of dye is directly proportional to density of fluid, Beer-Lambert's law is used to generate a calibration between intensity of the light measured by the camera and density of the fluid. Using this calibration, density is evaluated in all the images captured. In the parameter space of this study, the spheres have three different wake patterns. The area of fluid disturbed by a suspension of spheres increases with <i>Re</i> and <i>Fr</i>. As a result, the amount of energy available for the mixing and the irreversible change of total potential energy in the system increases with <i>Re</i>, <i>Fr</i> and number of particles. Cylinders drag volumes of light fluid to larger depths in their wake than spheres and shed the light fluid in the form of vortices. This results in lower volumes of fluid perturbed by the cylinders. However, as the light fluid is dragged to larger depths, the amount of energy generated for mixing and the change in total potential energy of the system is higher. Spheres are thus more efficient in disturbing volumes of fluid but cylinders are more efficient in causing irreversible changes to the state of the system.