Eur. Phys. J. D (2022) 76: 19
https://doi.org/10.1140/epjd/s10053-022-00353-2

Regular Article – Atomic and Molecular Collisions

New routes in the formation of positively charged fragments upon electron attachment

¹ CEFITEC, Departamento de Física, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
² LAQV, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
³ Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil

^f f.ferreiradasilva@fct.unl.pt
^g lucascor@unicamp.br

Received: 1 November 2021
Accepted: 20 January 2022
Published online: 4 February 2022

Abstract

Electron-driven reactions of CF${}_3$CH${}_2$F have been studied focusing on the formation of the parent cation, CF${}_3^{+}$ and CH${}_2$F${}^{+}$ (C–C bond cleavage) fragments as a function of the electron energy. For the three referred cations, an unpredicted shoulder structure is observed in the ion yield between 12 and 20 eV, indicating a resonant process (electron attachment). Viewing the observations as the result of a competition between the expected dissociative electron ionization and a dissociative electron attachment, we propose a new route where the formation of the transient anion, under two autodetachments, ultimately triggers the formation of positively charged fragments. The reaction $e^{-}+\text{AB}\to {\text{AB}}^{-\ast }\to {\text{AB}}^{\ast }+e^{-}\to {\text{A}}^{+}+\text{B}+2e^{-}$ is supported by both experimental data and scattering calculations.