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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.

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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).

In this research the so-called potential morphing method was used to generate reliable interaction potential energy surfaces for weakly bound complexes. The potential morphing method is based on the optimization of modified computed ab initio potential energy surfaces to give predicted spectroscopic data, in agreement with the experimental values. In the standard potential morphing procedure the computed ab initio potential is adjusted by scaling, shifting, and dilating transformations to reproduce the experimental data. In this research, selected systems have been chosen to be studied based on the availability of varied and accurate sets of experimental data. In the present work, accurate interaction potential energy surfaces are obtained for the weakly bound complexes: Ne:HCl, OC:HX (X = F, Cl, Br, I) and HI:CO2. A comprehensive study on the interaction potential of these systems provides fundamental perspectives on the influence of different intermolecular forces. In addition the ground state isotopic isomerization observed in the OC:HI system may suggest a possible structural change of proteins, and other biological macromolecules, in deuterated solvents. In this dissertation, an alternative approach to morphing the potential energy surfaces of non-covalent interactions is also presented. In this approach the morphed potential is generated as a linear combination of ab initio potentials, that are computed at different levels of theory. This new morphing approach is applied to OC:HCl and is found to be of similar accuracy to that of the previous morphing method. In addition, this new method is also extended from four-dimensions to six-dimensions and is applied to the OC:HF system to obtain a vibrationally-complete six-dimensional morphed potential.