Interstellar SiS(1Σ+) Formation through SiH(2Π) + S(3 P ): Reaction Dynamics and Vibrational Distribution

Abstract The interpretation of astronomical spectra obtained from radio telescopes requires data on the dynamics and kinetics of molecular collisions involving the detected species. Here, we report a dynamics and kinetics study of the reaction between the silylidyne radical and ground-state sulfur atoms. The quasi-classical trajectory (QCT) methodology is employed, using a previously reported global analytical potential energy surface for the ground electronic state of SSiH to represent the interatomic interaction. It is shown that the reaction rate constant depends on temperature in the range 10 < T/K < 200, while remaining nearly constant at higher values. Details on the reaction pathway are presented, and the nascent SiS is found to be vibrationally excited.