TRANSITION ENERGIES OF YTTERBIUM, LUTETIUM, AND LAWRENCIUM BY THE RELATIVISTIC COUPLED-CLUSTER METHOD

The relativistic Fock-space coupled-cluster method was applied to the Yb, Lu, and Lr atoms, and to several of their ions. A large number of transition energies was calculated for these systems. Starting from an all-electron Dirac-Fock or Dirac-Fock-Breit function, many electrons (30-40) were correlated to account for core-valence polarization. High-l virtual orbitals were included (up to l=5) to describe dynamic correlation. Comparison with experiment (when available) shows agreement within a few hundred wave numbers in most cases. Fine-structure splittings are even more accurate, within 30 cm-1 of experiment. Average errors are at least three times smaller than for previous calculations. Two bound states of Lu- are predicted, 6p5d 1D2 and 6p2 3P0, with binding energies of about 2100 and 750 cm-1, respectively. The ground state of lawrencium is 2P1/2, relativistically stabilized relative to 2D3/2, the ground state of Lu. Two states of the Lr- anion are bound, 7p2 3P0 (by 2500 cm-1) and 7p6d 1D2 (by 1300 cm-1). © 1995 The American Physical Society.