Acetaldehyde binding energies : a coupled experimental and theoretical study
Ferrero, Stefano (Universitat Autònoma de Barcelona. Departament de Química)
Grieco, F. (University of Ghent. Department of Physics and Astronomy)
Ibrahim Mohamed, A-S (Centre National de la Recherche Scientifique. Sorbonne Université)
Dulieu, François (Centre National de la Recherche Scientifique. Sorbonne Université)
Rimola Gibert, Albert (Universitat Autònoma de Barcelona. Departament de Química)
Ceccarelli, Cecilia (Centre National de la Recherche Scientifique. Université Grenoble Alpes)
Nervi, C. (Università degli Studi di Torino. Dipartimento di Chimica)
Minissale, M. (Centre National de la Recherche Scientifique. Aix-Marseille University)
Ugliengo, Piero (Università degli Studi di Torino. Dipartimento di Chimica)

Data:	2022
Resum:	Acetaldehyde is one of the most common and abundant gaseous interstellar complex organic molecules found in cold and hot regions of the molecular interstellar medium. Its presence in the gas-phase depends on the chemical formation and destruction routes, and its binding energy (BE) governs whether acetaldehyde remains frozen on to the interstellar dust grains or not. In this work, we report a combined study of the acetaldehyde BE obtained via laboratory temperature programmed desorption (TPD) experiments and theoretical quantum chemical computations. BEs have been measured and computed as a pure acetaldehyde ice and mixed with both polycrystalline and amorphous water ice. Both calculations and experiments found a BE distribution on amorphous solid water that covers the 4000-6000 K range when a pre-exponential factor of 1. 1×1018s−1 is used for the interpretation of the experiments. We discuss in detail the importance of using a consistent couple of BE and pre-exponential factor values when comparing experiments and computations, as well as when introducing them in astrochemical models. Based on the comparison of the acetaldehyde BEs measured and computed in the present work with those of other species, we predict that acetaldehyde is less volatile than formaldehyde, but much more than water, methanol, ethanol, and formamide. We discuss the astrochemical implications of our findings and how recent astronomical high spatial resolution observations show a chemical differentiation involving acetaldehyde, which can easily explained due to the different BEs of the observed molecules.
Ajuts:	European Commission 741002 European Commission 865657 European Commission 811312 European Commission 851622
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Astrochemistry ; Molecular data ; Molecular processes ; ISM: abundances
Publicat a:	Monthly Notices of the Royal Astronomical Society, Vol. 516, Issue 2 (October 2022) , p. 2586-2596, ISSN 1365-2966

DOI: 10.1093/mnras/stac2358

11 p, 1.3 MB

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