Two-component calculations of spin-orbit effects for a van der Waals molecule Rn-2

Electronic structures of the weakly bound Rn, were calculated by the two-co mponent Moller-Plesset second-order perturbation and coupled-cluster method s with relativistic effective core potentials including spin-orbit operator s. The calculated spin-orbit effects are small, but depend strongly on the size of basis sets and the amount of electron correlations. Magnitudes of s pin-orbit effects On D-e (0.7-3.0 meV) and R-e (-0.4 similar to -2.2 Angstr om) of Rn-2 are comparable to previously resorted values based on configura tion interaction calculations. A two-component approach seems to be a promi sing tool to investigate spin-orbit effects for the weak-bonded systems con taining heavy elements. (C) 1999 John Wiley & Sons, Int. Int J Quant Chem 7 2: 139-143, 1999.