Electronic Structure and Kinetics Calculations for the Si+SH Reaction, a Possible Route of SiS Formation in Star-Forming Regions

The reaction between atomic silicon and the mercapto radical has been computationally investigated by means of electronic structure and kinetics calculations to establish its possible role in the formation of interstellar SiS. According to our kinetics estimates based on the electronic structure calculations of the Si+SH potential energy surface, the reaction is very fast reaching the gaskinetics limit. Therefore, the title reaction is an efficient formation route of interstellar SiS provided that silicon atoms and mercapto radicals are present. Implications for the observation of an anomalously high abundance of SiS in the shocked region around a Sun-like protostar (L1157-B1) are also presented.