Relativistic multiconfiguration Hartree-Fock by means of direct perturbation theory

A relativistic direct perturbation theory approach has been implemented at the multiconfiguration Hartree-Fock level into the numerical program package LUCAS. The method has been applied to the closed-shell Be, Zn, Cd, and Hg atoms and to the rare gases Ne to Rn. The scalar relativistic valence-correlation correction to the rare gases is found to be very small, while for Zn, Cd, and Hg the first-order relativistic corrections to the valence-correlation energy are calculated to he -4.6, -6.3, and -17.4 mH, respectively. (C) 1997 John Wiley & Sons, Inc.