RELATIVISTIC AND CORRELATION-EFFECTS FOR ELEMENT 105 (HAHNIUM, HA) - A COMPARATIVE-STUDY OF M AND MO (M = NB, TA, HA) USING ENERGY-ADJUSTEDABINITIO PSEUDOPOTENTIALS

Nonrelativistic and quasirelativistic energy-adjusted ab initio pseudo potentials are presented for element 105 (hahnium,Ha) together with co rresponding energy-optimized valence basis sets. The method of energy adjustment of pseudopotentials is extended to a two-component formalis m and to multiconfiguration wave functions. The accuracy of the pseudo potential scheme is demonstrated by a comparison of atomic valence-onl y results to corresponding all-electron data. Atomic multiconfiguratio n self-consistent field and multireference configuration interaction c alculations for M and M+ (M = Nb, Ta, Ha) are compared with available experimental data. Corresponding molecular calculations, which include d spin-orbit coupling, have been performed for the low-lying states of HaO and are compared to the results from corresponding calculations o f the lighter homologs NbO and TaO.