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arXiv · 2405.12092

A Possible Additional Formation Pathway for the Interstellar Diatomic SiS

Ryan C. Fortenberry·Brett A. McGuire
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Abstract

The formation of silicon monosulfide (SiS) in space appears to be a difficult process, but the present work is showing that a previously excluded pathway may contribute to its astronomical abundance. Reaction of the radicals SH + SiH produces SiS with a submerged transition state and generates a stabilizing H$_2$ molecule as a product to dissipate the kinetic energy. Such is a textbook chemical reaction for favorable gas-phase chemistry. While previously proposed mechanisms reacting atomic sulfur and silicon with SiH, SH, and H$_2$S will still be major contributors to the production of SiS, an abundance of SiS in certain regions could be a marker for the presence of SiH where it has previously been unobserved. These quantum chemically-computed reaction profiles imply that the silicon-chalcogen chemistry of molecular clouds, shocked regions, or protoplanetary disks may be richer than previously thought. Quantum chemical spectral data for the intermediate cis- and trans-HSiSH are also provided in order to aid in their potential spectroscopic characterization.

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Ryan C. Fortenberry, Brett A. McGuire. 2024-05-20. A Possible Additional Formation Pathway for the Interstellar Diatomic SiS. https://arxiv.org/abs/2405.12092

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