Interaction of HCO+ cations with interstellar negative frains. Quantum chemical investigation and astrophysical implications
Rimola, Albert (Universitat Autònoma de Barcelona. Departament de Química)
Ceccarelli, Cecilia (Centre National de la Recherche Scientifique. Université Grenoble Alpes. Institut de Planétologie et d'Astrophysique de Grenoble)
Balucani, Nadia (Università degli Studi di Perugia. Dipartimento di Chimica, Biologia e Biotecnologie)
Ugliengo, Piero (Università degli Studi di Torino. Dipartimento di Chimica and Nanostructured Interfaces and Surfaces Centre)

Data:	2021
Resum:	In cold galactic molecular clouds, dust grains are coated by icy mantles and are prevalently charged negatively, because of the capture of the electrons in the gas. The interaction of the charged grains with gaseous cations is known to neutralize them. In this work, we focus on the chemical consequences of the neutralization process of HCO+, often the most abundant cation in molecular clouds. More specifically, by means of electronic structure calculations, we have characterized the energy and the structure of all possible product species once the HCO+ ion adsorbs on water clusters holding an extra electron. Two processes are possible: (i) electron transfer from the negative water cluster to the HCO+ ion or (ii) a proton transfer from HCO+ to the negative water cluster. Energetic considerations favor electron transfer. Assuming this scenario, two limiting cases have been considered in astrochemical models: (a) all the neutralized HCO+ is retained as neutral HCO adsorbed on the ice and (b) all the neutralized HCO+ gets desorbed to the gas phase as HCO. None of the two limiting cases appreciably contribute to the HCO abundance on the grain surfaces or in the gas.
Ajuts:	European Commission 865657 European Commission 741002 European Commission 811312 Agencia Estatal de Investigación CTQ2017-89132-P Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1323
Drets:	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.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	DFT ; Water ice ; Solvated electron ; Astrochemical modeling ; Interstellar medium
Publicat a:	Frontiers in Astronomy and Space Sciences, Vol. 8 (April 2021) , art. 655405, ISSN 2296-987X

DOI: 10.3389/fspas.2021.655405

10 p, 3.9 MB

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