A SIMPLE PREDICTIVE MODEL OF CHEMICAL-POTENTIALS - H-2(1-SIGMA-G) AND LI-2(1-SIGMA-G)

A simple model for van der Waals potentials presented earlier [J. Chem. Phys. 80, 3726 (1984)] has been extended to describe chemical bonds by including the exchange-dispersion term of Herring and Flicker. For H-2, the 1-SIGMA ground state potential is predicted in excellent agreement with the accurately known ab initio potential, the well depth being reproduced to within 0.6%. New two configuration self-consistent-field (SCF) calculations for the 1-SIGMA and the 3-SIGMA states of Li2 have made it possible to test the model for this system as well. Here the discrepancy is only 3% in the well depth for the 1-SIGMA Li2 potential.