An Application of the Pariser-Parr Approximation to the Hydrogen Molecule

摘要

The semi-empirical method due to Pariser and Parr (J. Chem. Phys. v21 p466 1953) is extended to make it applicable to an axially symmetrical molecule. The method is used to calculate, for fixed nuclei, the energies, relative to the singlet-Sigma(+) sub G ground term, of those six spectroscopic terms which can be obtained from the ground term by exciting one of the pi-u 2p electrons to a pi-G 2p orbital. Agreement with experiment is satisfactory for those excited states which are not strongly affected by a neglected electronic configuration. Formulae are given for certain valence-state energies, additional to those earlier published (Mol. Phys. v4 p505 1961). (Author)