Experimental And Computational Studies Of The Hydrogenation Of Carbon Disulfide (CS2) On Ice Analogues

Carbon disulfide (CS₂) is one of the sulfur-bearing species expected to be present in the interstellar medium (ISM). In this study, we investigated the surface reactions of solid CS₂ with hydrogen (H) atoms on amorphous solid water (ASW) using laboratory experiments supported by computational calculations.

Our results show that CS₂ reacts with H atoms through quantum tunneling in the initial step, followed by successive H addition reactions, with or without activation barriers, on icy surfaces.

These processes lead to the formation of several sulfur-bearing species, including hydrogen sulfide (H₂S), methyl mercaptan (CH₃SH), and small amounts of dithioformic acid (HC(S)SH) and methanedithiol (CH₂(SH)₂). The observed reactivity of CS₂ with H atoms provides a plausible explanation for the non-detection of CS₂ in interstellar ices.

Furthermore, the efficient hydrogenation of the complex molecules derived from CS₂, namely HC(S)SH and CH₂(SH)₂, suggests that these species could be easily undergone with H atoms to produce other S-bearing species under ISM conditions.

Thanh Nguyen, Germán Molpeceres, Yasuhiro Oba, Marcelino Agúndez, Gisela Esplugues, José Cernicharo, Naoki Watanabe

Comments: Accepted in MNRAS
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2602.21126 [astro-ph.GA](or arXiv:2602.21126v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2602.21126
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Submission history
From: German Molpeceres
[v1] Tue, 24 Feb 2026 17:22:37 UTC (2,144 KB)
https://arxiv.org/abs/2602.21126

Astrobiology,