Revealing SO2 and CO2 adsorption features on forsterite via IR spectroscopy and automated computational approaches
Mates-Torres, Eric (Universitat Autònoma de Barcelona. Departament de Química)
Escolano Casado, G. (Università degli Studi di Torino. Dipartimento di Chimica)
Mino, Lorenzo (University of Torino. Department of Chemistry and Nis Centre)
Balucani, Nadia (Università degli Studi di Torino. Dipartimento di Chimica)
Ugliengo, Piero (Università degli Studi di Torino. Dipartimento di Chimica)
Rimola Gibert, Albert (Universitat Autònoma de Barcelona. Departament de Química)

Date:	2025
Abstract:	The interaction between interstellar molecules and silicate dust plays a critical role in the chemical evolution of interstellar and circumstellar environments. In this work, we combine in situ infrared (IR) spectroscopy with automated density functional theory (DFT) calculations to investigate the adsorption and vibrational signatures of CO and SO on forsterite surfaces. Experimental IR spectra collected under cryogenic conditions reveal coverage- and temperature-dependent features that evolve from physisorbed to chemisorbed regimes. To interpret these observations, we construct theoretical spectra from a large ensemble of adsorption configurations across multiple surface terminations, weighted by their Boltzmann distributions at 100 K and by a per-surface abundance factor. The resulting spectra reproduce key experimental features, enabling the identification of binding trends. For CO, we predict the transition from weakly bound species to carbonate-like modes at lower frequencies. For SO, our simulations identify the dominant bands due to bidentate and tridentate chemisorption. This integrative approach highlights the importance of surface morphology and thermodynamic weighting in reconciling theory and experiments providing a framework for the spectroscopic analysis of molecular adsorption on interstellar dust analogs.
Grants:	European Commission 865657 Agencia Estatal de Investigación PID2021-126427NBI00 Agencia Estatal de Investigación CNS2023-144902
Note:	Altres ajuts: acords transformatius de la UAB
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Published in:	Physical Chemistry Chemical Physics, Vol. 27, Issue 24 (June 2025) , p. 13124-13134, ISSN 1463-9076

DOI: 10.1039/d5cp01699a
PMID: 40488652

11 p, 1.8 MB

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