GROUND-STATE PROPERTIES OF HG-2 .1. A PSEUDOPOTENTIAL CONFIGURATION-INTERACTION STUDY

The results of large-scale relativistic ab initio pseudopotential calc ulations for the potential curve of the (1) Sigma(g)(+) (0(g)(+)) grou nd state of the mercury dimer Hg-2 are reported. Various methods to ac count for electron correlation effects have been applied in the Lambda Sigma coupling scheme, and spin-orbit contributions were derived from calculations in the intermediate coupling scheme. The importance of c orrelating the 5s,5p core orbitals in addition to the 5d core and 6s v alence orbitals and of spin-orbit corrections is demonstrated. At the highest level of approximation the calculated spectroscopic constants (R(e) = 3.73 Angstrom, D-e = 0.047 eV, omega(e) = 19 cm(-1)) are in ex cellent agreement with the experimental results (R(e) = 3.63 +/- 0.04 Angstrom, D-e = 0.043 +/- 0.003 eV, omega(e) = 18.5 +/- 0.5 cm(-1)).