SPIN-ORBIT EFFECTS CALCULATED BY 2-COMPONENT COUPLED-CLUSTER METHODS - TEST CALCULATIONS ON AUH, AU-2, TLH AND TL-2

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