Two-dimensional, fully numerical solution of the molecular Dirac equation. Dirac-Slater calculations on LiH, Li 2, BH and CH +

Abstract

Four-component, second-order Dirac-Slater calculations are reported for LiH, Li 2, BH and CH +. Relativistic corrections to the total energies, bond lengths, vibrational frequencies and electric multipole moments are given. Dirac-Fock results are presentedfor H 2. The origin of the relativistic bond contraction is discussed. The relativistic corrections to the dipole moment of LiH are shown to be of the same order of magnitude as the basis set truncation error, at the HF level, for the accurate LCAO calculations.