Formation of CO, CH4, H2CO and CH3CHO through the H2CCO + H surface reaction under interstellar conditions - Université de Rennes Accéder directement au contenu
Article Dans Une Revue Physical Chemistry Chemical Physics Année : 2022

Formation of CO, CH4, H2CO and CH3CHO through the H2CCO + H surface reaction under interstellar conditions

Résumé

The reaction of ketene (H2CCO) with hydrogen atoms has been studied under interstellar conditions through two different experimental methods, occurring on the surface and in the bulk of H2CCO ice. We show that ketene interaction with H-atoms at 10 K leads mainly to four reaction products, carbon monoxide (CO), methane (CH4), formaldehyde (H2CO) and acetaldehyde (CH3CHO). A part of these results shows a chemical link between a simple organic molecule such as H2CCO and a complex one such as CH3CHO, through H-addition reactions taking place in dense molecular clouds. The H-addition processes are very often proposed by astrophysical models as mechanisms for the formation of complex organic molecules based on the abundance of species already detected in the interstellar medium. However, the present study shows that the hydrogenation of ketene under non-energetic conditions may also lead efficiently to fragmentation processes and the formation of small species such as CO, CH4 and H2CO, without supplying external energy such as UV photons or high energy particles. Such fragmentation pathways should be included in the astrophysical modeling of H2CCO + H in the molecular clouds of the interstellar medium. To support these results, theoretical calculations have explicitly showed that, under our experimental conditions, H-atom interactions with the C[double bond, length as m-dash]C bond of ketene lead mainly to CH3CHO, CH4 and CO. By investigating the formation and reactivity of the reaction intermediate H3C–C[double bond, length as m-dash]O radical, our calculations demonstrate that the H3C–C[double bond, length as m-dash]O + H reaction evolves through two barrierless pathways to form either CH3CHO or CH4 and CO fragments.
Fichier principal
Vignette du fichier
accepted-CH2CO-Hydrogenation 2022.pdf (1.97 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-04248817 , version 1 (18-10-2023)

Identifiants

Citer

Mohamad Ibrahim, Jean-Claude Guillemin, Patrick Chaquin, Alexis Markovits, Lahouari Krim. Formation of CO, CH4, H2CO and CH3CHO through the H2CCO + H surface reaction under interstellar conditions. Physical Chemistry Chemical Physics, 2022, 24 (38), pp.23245-23253. ⟨10.1039/D2CP02980D⟩. ⟨hal-04248817⟩
126 Consultations
91 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More