The application of Green's function techniques to the study of atomic and molecular properties /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1990.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | The multiconfigurational time dependent Hartee-Fock (MCTDHF) approximation to the polarization propagator, the multiconfigurational spin-tensor electron propagator (MCSTEP) approximation to the electron propagator, and the multiconfigurational particle-particle propagator (MCP2P) approximation to the particle-particle propagator are studied. The MCTDHF approximation is used to study Be atom. The low lying excitation energies the oscillator strengths for transitions to the five lowest 1P^O states and the frequency dependent and independent polarizabilities of a number of states are calculated using a <9s9p5d> GTO basis set. The excitation energies differ from the ΔCl excitation energies by 0.01 eV on average. This approximation is also used to study the transition moments for the first positive system and the infrared afterglow of N2 using a <8s5p3d1f> GTO basis set for each atom. These calculations agree very well with a previous very large Cl calculation. The low-lying adiabatic ionization potentials (IPs) from the 2B[1] ground state of NH2 are calculated at the MCSTEP level of approximation. This calculation has aided in the interpretation of the very complicated photoelectron spectrum of NH2. This approximation is also used to calculate very accurately the electron affinities (EAs) of Li, Na, and K. The MCP2P approximation to the particle-particle propagator for the determination of double ionization potentials (DIPs) and double electron affinities (DEAs) is developed. The reference state used is a correlated multiconfigurational reference state. The operator manifold allows for simple double electron removal from the fully occupied/partially occupied orbital space, simple double electron addition to the virtual/partially occupied orbital space, and simple double electron removal (and addition) from the partially occupied orbital space along with any simultaneous electronic excitations within this space. This approximation is implemented for large-scale calculations. A modified version of the block Davidson algorithm is developed to solve the generalized eigenvalue problem. This takes into account the existence of a non-unit metric and allows for non-diagonally dominant matrices to be diagonalized. The low-lying DIPs of Be atom are calculated very accurately using an <11s9p3d> GTO basis set. They differ from experiment by 0.35 eV on average. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Chemistry." |
| Physical Description: | xiv, 197 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |