Spin-orbit effects calculated by two-component coupled-cluster methods: test calculations on AuH, Au-2, TlH and Tl-2

Abstract

We have modified the MOLFDIR code by Visscher and coworkers to use one electron integrals of relativistic effective core potentials with spin-orbit operators and two-component molecular spinors for polyatomic molecules. The present methods incorporate spin-orbit interactions from the Hartree-Fock step through the use of two-component molecular spinors confirming Kramers' degeneracy and are particularly useful to estimate spin-orbit effects. Test calculations for the ground states of AuH, Au-2, TIH and TI2, are performed to show that spin-orbit effects vary depending upon the level of theory employed. (C) 1998 Elsevier Science B.V. All rights reserved.