Theoretical study on the reaction of VS + ( 3Σ −, 1Γ) with COS in the gas phase

Abstract

Two possible reaction channels of VS + ( 3Σ − and 1 Γ states) with COS in the gas phase have been studied by using density functional theory at B3LYP/DZVP level: the O/S exchange reaction ( VS + + COS → VO + + CS 2 ) and the S-transfer reaction ( VS + + COS → VS 2 + + CO ) . The different mechanisms on the triplet and singlet surfaces have been identified. It is found that the S-transfer reaction proceeds via two parallel reaction paths (path A and B) yielding two isomer products ( VS 2 + − 1 and VS 2 + - 2 , respectively), and the exothermicity with endothermic feature of the formation of VS 2 + observed experimentally can be attributed to these two reaction paths with the calculation reaction heats of −20.5 and 70.5 kJ/mol, respectively, on the ground triplet surface. The larger barrier (103.6 kJ/mol) of the O/S exchange reaction and the smaller probability of the formation of its preceding intermediate ( 3 IM1) indicate the much less efficiency of the reaction, which is in agreement with the experimental observation.