Direct fit of extended Hartree–Fock approximate correlation energy model to spectroscopic data

By direct-fitting the parameters in the physically motivated extended Hartree–Fock approximate correlation energy model to spectroscopic data, potential curves have been obtained for a variety of diatomic systems that mimic the ro-vibrational data often within much less than 1 cm−1. The approach offers a simple, yet accurate, scheme for modeling the two-body terms that are the leading contributions in a cluster expansion of potential energy surfaces of larger dimensionality.