I. Projected G1 wavefunctions for He₂. II. Localized wavefunctions for H₂O, OH, and O

Author: Guberman, Steven Lawrence

Year: 1973

Degree: Dissertation (Ph.D.)

Advisor: Goddard, William A., III

Committee Member: Unknown, Unknown

Option: Chemistry

DOI: 10.7907/TA01-KS50

Abstract

I. The low-lying excited states of He_2 have been examined using projected Generalized Valence Bond wavefunctions. Two types of interactions are shown to be important in understanding the anomalous maxima and the general shapes of the curves. The interaction between core orbitals on opposite centers is important at small R whereas at large R the dominant interaction is between core and Rydberg orbitals on opposite centers. The latter effect is expressible in terms of the exchange kinetic energy and arises from the repulsion between singlet coupled pairs of orbitals. This is described simply in terms of the shapes of the Rydberg orbitals. The results in general agree favorably with experiment where such comparison can be made.

II. Localized wavefunctions obtained from applying an external localization criterion to orbitals resulting from the GF method are reported for H_2O, OH, and 0. The shapes and angles between the orbitals are described in some detail. It is shown that the resulting GF orbitals change in a chemically reasonable manner as we proceed from 0 to OH to H_2O.

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