ELUCIDATION OF THE STRUCTURAL CHARACTERISTICS OF THE ISOVALENT SPECIES LI[CO] AND LI[CS] BY AB-INITIO CALCULATIONS

We have performed ab initio CISD(+corrections) calculations on the val ence isoelectronic molecules Li[CO] and Li[CS] using large basis sets. The Li-CO, Li-OC, LI-CS and Li-SC (II)-I-2 states are bound with resp ect to Li P-2 by 38, 8, 70 and 41 kcal/mol, respectively. With the exc eption of LiCS C-2 Sigma(+), which presents a shallow minimum of 4 kca l/mol, all the relevant (2) Sigma(+) states examined are repulsive. Fu ll potential energy curves are also presented for the most interesting of the states.