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

Two possible reactions of NbS+ (3Σ−, 1Γ) with CO in the gas phase have been studied by using B3LYP and CCSD(T) methods: the O/S exchange reaction (NbS+ + CO → NbO+ + CS) and the S-transfer reaction (NbS+ + CO → Nb+ + COS). The two reactions have a one-step mechanism. The barriers of the O/S exchange reaction on the triplet and singlet surfaces are 51.2 and 52.4 kcal/mol, respectively, and the barriers of the S-transfer reaction are 58.3 and 78.0 kcal/mol, respectively. The results indicate that the S-transfer and the O/S exchange reaction of the 3Σ− ground state of NbS+ are competing, but, for the S-transfer reaction, the 1Γ exited state is more reactive. The differences between the reactions of NbS+ (3Σ−, 1Γ) and VS+ (3Σ−, 1Γ) are discussed.