Ab initio study of reaction mechanism of C2+H2S

The reaction mechanism of C2+H2S has been investigated using ab initio method. On the basis of calculations using CCSD(T) in conjunction with 6-311++G(d, pd) basis set with the geometry optimized at MP2/6-311++G** level, the H-abstraction reaction on the triplet energy potential surface is an exothermic process with formation of a precomplex as an intermediate, which further dissociate to yield HS(2Σ+)+CCH(2Σ+) with an energy barrier of 4.9 kcal mol−1. The addition of H2S(1A1) to C2(1Σg+) on leads to a bound intermediate H2SCC(1A′) (3,3-dihydrodicarbonsulfide), which can further isomerize into HSCCH(1A) (thiohydroxyacetylene) in a one-step hydrogen migration process.