Erlangen 2022 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 16: Ions
MO 16.3: Vortrag
Donnerstag, 17. März 2022, 11:15–11:30, MO-H5
Disentangling elimination and nucleophilic substitution dynamics — •Tim Michaelsen1, Jennifer Meyer1, Viktor Tajti2, Eduardo Carrascosa1, Tibor Györi2, Martin Stei1, Björn Bastian1, Gábor Czakó2, and Roland Wester1 — 1Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria — 2Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, University of Szeged, Szeged, Hungary
In the presented study we combine angle- and energy-differential cross sections, obtained in a crossed-beam velocity map imaging experiment, with quasi-classical trajectory (QCT) calculations on an accurate 21-dimensional hypersurface to disentangle the competition of base induced elimination (E2) and nucleophilic substitution (SN2) in the reaction of F− with CH3CH2Cl [1]. As the detected product ion Cl− is identical for SN2, anti and syn-E2, separating the pathways from experiment alone is very challenging. The QCT calculations quantitatively reproduce the measured total experimental cross section due to their novel accuracy for such polyatomic reactions and allow us to differentiate the competing channels and extract detailed information on the underlying reaction mechanisms. We find that the anti-E2 pathway is dominant, but that SN2 contributions become more important towards larger collision energies.
[1] J. Meyer, V. Tajti, E. Carrascosa et al., Nat. Chem. 13, 977-981 (2021)