Theoretical study on the reaction of VS+(3∑−, 1Γ) with CO

Two possible reaction mechanisms of VS+ (3∑−, 1Γ) with CO in the gas phase have been studied by using B3LYP/TZVP and CCSD(T)/6-311+G (3df, 3pd) methods: the O/S exchange reaction (VS+ + CO → VO+ + CS) and the S-transfer reaction (VS+ + CO → V+ + COS). The two reactions proceed via two-step and one-step mechanism, respectively. The barriers of the triplet and singlet PESs are 30.6 and 50.9 kcal/mol, respectively, for O/S exchange reaction and 7.3 and 50.2 kcal/mol, respectively, for the S-transfer reaction. The results indicate that the triplet ground state reaction is more favorable, and the S-transfer reaction is more favorable than the O/S exchange reaction, which is in good agreement with the experimental observation.