Formation of CO, CH4, H2CO and CH3CHO through the H2CCO + H surface reaction under interstellar conditions.
Phys Chem Chem Phys
; 24(38): 23245-23253, 2022 Oct 05.
Article
em En
| MEDLINE
| ID: mdl-36134501
ABSTRACT
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 CîC bond of ketene lead mainly to CH3CHO, CH4 and CO. By investigating the formation and reactivity of the reaction intermediate H3C-CîO radical, our calculations demonstrate that the H3C-CîO + H reaction evolves through two barrierless pathways to form either CH3CHO or CH4 and CO fragments.
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Bases de dados:
MEDLINE
Idioma:
En
Revista:
Phys Chem Chem Phys
Assunto da revista:
BIOFISICA
/
QUIMICA
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
França