Analytical potential energy functions and theoretical spectroscopic constants for MX/MX- (M = Ge, Sn, Pb; X = O, S, Se, Te, Po) and LuA (A = H, F) systems:: Density functional theory calculations

The molecular spectroscopic constants for the chalcogenide complexes MX (M=Ge, Sn, Pb; X=O, S, Se, Te, Po) and their corresponding MX- anions are presented with the LSDA/SDD, B1LYP/SDD, and B3LYP/SDD methods. Although many methods were attempted, only the most promising results are reported. We show that the best results are obtained by LSDA/SDD calculations, and thus this method is emphasized as an illustrative example of our methodology. The potential energy curves and physical property characterizations for X-1 Sigma(+) state of LuH and LuF are presented with a variety of density functional theory (DFT) methods. Comparisons with wave function-based treatments (HF, MP2, CCSD, QCISD) are made in addition to experimental correlations. We show that the best results are obtained by the B3LYP/ SDD method for LuH, and the MPWlPW91/SDD method for LuF. (C) 2006 Wiley Periodicals, Inc.