Abstract
The wavelength control of photochemistry usually results from ultrafast dynamics following the excitation of different electronic states. Here, we investigate the CF3COCl molecule, exhibiting wavelength-dependent photochemistry both via (i) depositing increasing internal energy into a single state and (ii) populating different electronic states. We reveal the mechanism behind the photon-energy dependence by combining nonadiabatic ab initio molecular dynamics techniques with the velocity map imaging experiment. We describe a consecutive mechanism of photodissociation where an immediate release of Cl taking place in an excited electronic state is followed by a slower ground-state dissociation of the CO fragment. The CO release is subject to an activation barrier and is controlled by excess internal energy via the excitation wavelength. Therefore, a selective release of CO along with Cl can be achieved. The mechanism is fully supported by both the measured kinetic energy distributions and anisotropies of the angular distributions. Interestingly, the kinetic energy of the released Cl atom is sensitively modified by accounting for spin–orbit coupling. Given the atmospheric importance of CF3COCl, we discuss the consequences of our findings for atmospheric photochemistry.
Original language | English |
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Pages (from-to) | 2275–2286 |
Number of pages | 12 |
Journal | ACS Earth and Space Chemistry |
Volume | 7 |
Issue number | 11 |
Early online date | 16 Oct 2023 |
DOIs | |
Publication status | Published - 16 Nov 2023 |
Bibliographical note
Funding Information:J.J. and P.S. thank the Czech Science Foundation (project no. 23-07066S) and the experimental group M.F., I.S.V., J.R., and D.P.M. thank project no. 2107062S. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 803718, project SINDAM) and the EPSRC grant EP/V026690/1 (B.F.E.C.).
Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society.