LCGTO MP LSD calculations for the diatomics PdX (X = C,Si, Ge,Sn)

Results are presented of a theoretical study of RhC, PdC, PdSi, PdGe and PdSn metal-alloy diatomics performed with the LCGTO MP LSD method. For the RhC molecule the computed electronic structure and spectroscpic constants are in good agreement with experimental data. The ground state of RhC is found to be ²Σ⁺ withe the lowest-lying excited state, ²II, at 10654 cm⁻¹ above the ground state, in good agreement with experiment and with ab initio CI calculations. For PdC and the other Pd-group IV A dimers the ground state is predicted to be ¹Σ and the two lowest-lying excited state are ³II (at 2718 cm⁻¹ for PdC) and ³gS (at 12164 cm⁻¹ for PdC). Our results are in disagreement with ab initio CI studies for PdC, which found a ³Σ ground state with a ³II lowest-lying excited state, and for PdGe, which found a ³II ground state followed by ³Σ⁻ and ¹Σ⁺.