Electron-triggered processes in halogenated carboxylates: Dissociation pathways in CF3COCl and its clusters

0581754 - ÚFCH JH 2025 RIV GB eng J - Journal Article
Kocábková, Barbora - Ďurana, Jozef - Rakovský, Jozef - Pysanenko, Andriy - Fedor, Juraj - Ončák, M. - Fárník, Michal
Electron-triggered processes in halogenated carboxylates: Dissociation pathways in CF3COCl and its clusters.
Physical Chemistry Chemical Physics. Roč. 26, č. 6 (2024), s. 5640-5648. ISSN 1463-9076. E-ISSN 1463-9084
R&D Projects: GA ČR(CZ) GA21-07062S; GA MŠMT(CZ) LTC20067
Institutional support: RVO:61388955
Keywords : molecular dynamics * gas phase * electron-triggered processes
OECD category: Physical chemistry
Impact factor: 3.3, year: 2022
Method of publishing: Open access
https://pubs.rsc.org/en/Content/ArticleLanding/2024/CP/D3CP05387C

Trifluoroacetyl chloride, CF3COCl, is produced in the Earth’s atmosphere by photooxidative degradation of hydrochlorofluorocarbons, and represents a potential source of highly reactive halogen radicals. Despite considerable insight obtained into photochemistry of CF3COCl, its reactivity towards electrons has not been addressed so far. We investigate the electron ionization and attachment in isolated CF3COCl molecules and (CF3COCl)N , max. N ≥ 10, clusters using a molecular beam experiment combined with quantum chemical calculations. The ionization of the molecule at 70 eV electron energy leads to a strong fragmentation: weakening of C–C bond yields the CF3+ and COCl+ ions, while the fission of C–Cl bond produces the major CF3CO+ fragment ion. The cluster spectra are dominated by Mn·COCl+ and Mn·CF3CO+ ions (M = CF3COCl). The electron attachment at energies between 1.5–11 eV also leads to the dissociation of the molecule breaking either C–Cl bond at low energies below 3 eV yielding mainly Cl− ion, or dissociating the C–C bond at higher energies above 4 eV leading mainly to CF3− ion. In the clusters, the intact M− n ions are stabilized after the electron attachment at low energies with a contribution of Mn·Cl− fragment ions. At the higher energies, the Mn·Cl− fragments dominate the spectra, and C–C bond dissociation occurs as well yielding Mn·CF3− . Interestingly, Mn·Cl2− ions appear in the spectra at higher energies. We briefly discuss possible atmospheric implications.

Permanent Link: https://hdl.handle.net/11104/0349909