Heidelberg 2015 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 13: Collisions & Energy Transfer
MO 13.2: Vortrag
Mittwoch, 25. März 2015, 11:30–11:45, PH/SR106
Imaging the influence of vibrational excitation in ion-molecule reactions — •Martin Stei1, Eduardo Carrascosa1, Alexander Dörfler2, Martin Kainz1, Jennifer Meyer1, and Roland Wester1 — 1Institute for Ion Physics and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria — 2now at: Department of Chemistry, University of Basel, 4056 Basel, Switzerland
We study the dynamics of ion-molecule reactions by kinematically complete velocity map imaging in a crossed-beam setup [1]. One major focus of our research is reactions of halide anions with methylhalides, a model system for nucleophilic substitution (SN2) reactions [2]. An open question is how vibrational excitation of the reactant molecules would influence these reaction.
Here, we report on reactions of F− and Cl− with vibrationally excited CH3I in the CH3 symmetric stretch (v1) mode. This excitation is provided by rotationally selective excitation of the 0R(3) line with a narrowband dye laser and probed by REMPI.
For F− we find an enhancement of the rate of the proton transfer channel for the excited vibrational state. We will discuss the implications of our findings for the SN2 channel.
[1] R. Wester, Phys. Chem. Chem. Phys. 16, 396 (2014) [2] J. Xie, R. Otto, J. Mikosch, J. Zhang, R. Wester, and W. L. Hase, Acct. Chem. Res. 47, 2960 (2014)