Very Accurate Coupled Cluster Calculations for Diatomic Systems with Numerical Orbitals

Abstract

Correlation energies and electron affinities for ground and excited states of polar diat. systems are investigated. Very accurate methods that combine purely numerical solns. to Hartree-Fock and Bethe-Goldstone equations for orbitals, with coupled-cluster and many-body perturbation methods for electron correlation, are able to obtain 99% of the correlation energy of LiH and 97% for FH. Such methods are thought to be sufficiently accurate that it is meaningful to use these techniques to obtain correlated electron affinities for excited states of diat. mols. The first results for excited state affinities are reported for BeO and LiH. [on SciFinder(R)]