Molecular Binding in the Limit of Very Large Spin—Orbit Interaction

Abstract

Binding energies and electronic wavefunctions are found for diatomic and methanelike molecules under the restriction that the electronic configuration contains only j = l—½ states. Two models for a diatomic molecule are treated. In the first, the electronic configuration is a p state on one atom and the effect of the other atom is included by a crystal field. In the second model the configuration is an s state on one atom and a p state on the other. The magnitude of the spin—orbit interaction required to make the restriction to j = l—½ states a good approximation is found in each case. In the second case, the binding is reduced by a factor of 3 by the restriction. In the methane molecule the restriction to j = l—½ states requires the inclusion of d states in the configuration. The binding of the methane can be increased by a distortion and experimental evidence for such a distortion in GeH4 and SiH4 is pointed out. Application of this approximation to the electronic structure of actinide complexes is briefly discussed.