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

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