Elucidation of the structural characteristics of the isovalent species Li[CO] and Li[CS] by ab anitio calculations

We have performed ab initio CISD(+ corrections) calculations on the valence isoelectronic molecules Li[CO] and Li[CS] using large basis sets. The LiCo, LiOC, LiCS and LiSC2Π states are bound with respect to Li 2P by 38, 8, 70 and 41 kcal/mol, respectively. With the exception of LiCS 2Σ+, which presents a shallow minimum of 4kcal/mol, all the relevant 2Σ+ states examined are repulsive. Full potential energy curves are also presented for the most interesting of the states.