Small-core multiconfiguration-Dirac-Hartree-Fock-adjusted pseudopotentialsfor post-d main group elements: Application to PbH and PbO

Relativistic pseudopotentials (PPs) of the energy-consistent variety have b een generated for the post-d group 13-15 elements, by adjustment to multico nfiguration Dirac-Hartree-Fock data based on the Dirac-Coulomb-Breit Hamilt onian. The outer-core (n-1)spd shells are explicitly treated together with the nsp valence shell, with these PPs, and the implications of the small-co re choice are discussed by comparison to a corresponding large-core PP, in the case of Pb. Results from valence ab initio one- and two-component calcu lations using both PPs are presented for the fine-structure splitting of th e ns(2)np(2) ground-state configuration of the Pb atom, and for spectroscop ic constants of PbH (X (2)Pi(1/2), (2)Pi(3/2)) and PbO (X (1)Sigma(+)). In addition, a combination of small-core and large-core PPs has been explored in spin-free-state shifted calculations for the above molecules. (C) 2000 A merican Institute of Physics. [S0021-9606(00)30531-1].