Binding Energy Distributions Of Alcohols, Thiols, And Their Precursors On Interstellar Water Ice Surfaces

Binding energy (BE) is a critical parameter in astrochemical modeling, governing the retention of species on interstellar dust grains and their subsequent chemical evolution.

However, conventional models often rely on single-valued BEs, overlooking the intrinsic distribution arising from diverse adsorption sites. In this study, we present BEs for monohydric alcohols, thiols, and their plausible precursors, including aldehydes and thioaldehydes.

We incorporate a distribution of BEs to capture the realistic variation in adsorption strengths. The quantum chemical calculations provide a range of BE values rather than a single estimate, ensuring a more precise description of molecular diffusion and surface chemistry.

The BE trend of analogous species provides qualitative insight into the dominant reaction pathways and key precursors that drive the formation of larger molecules under interstellar conditions. Oxygen-bearing species generally exhibit higher BEs than their sulfur analogues, primarily due to stronger interactions, further influencing molecular adsorption and reactivity.

We implemented BE distributions in astrochemical models, revealing significant effects on predicted abundances and establishing a more accurate framework for future astrochemical modeling.

The most stable ASW [H₂O]20 cluster structure (bottom). The other ASW clusters with their relative energies are available in the appendix (available on Zenodo) of Sil et al. (2024). Red, white, grey, and yellow balls represent Oxygen, Hydrogen, Carbon, and Sulfur atoms, respectively. — astro-ph.GA

Arghyadeb Roy, Ankan Das, Milan Sil, Prasanta Gorai, Kenji Furuya, Naoki Nakatani, Takashi Shimonishi

Comments: 14 pages, 6 figures, To be published in Life Sciences in Space Research (LSSR) Journal
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2509.00431 [astro-ph.GA] (or arXiv:2509.00431v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2509.00431
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Submission history
From: Arghyadeb Roy
[v1] Sat, 30 Aug 2025 09:26:59 UTC (941 KB)
https://arxiv.org/abs/2509.00431

Astrobiology, Astrochemistry,