Hannover 2016 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 2: Collisions, Energy transfer and ab initio Modelling
MO 2.1: Vortrag
Montag, 29. Februar 2016, 11:00–11:15, f142
Studying competing reaction pathways in F− + CH3I using 3D velocity map imaging — •Tim Michaelsen, Eduardo Carrascosa, Jennifer Meyer, Björn Bastian, Martin Stei, and Roland Wester — University of Innsbruck, Austria
We study ion-molecule reactions in a kinematically complete way using velocity map imaging in a crossed-beam setup [1,2]. A major focus of our group are substitution reactions of halide anions with methyl halides. Due to a fruitful collaboration between theory and experiments a lot of insight into the mechanics of these SN2 reactions was gained [3]. Beyond these, at sufficiently high collisional energies and entrance geometries other reaction channels become available and we will focus on these here. Specifically, we present in this talk the reaction of F− + CH3I where we observed three additional reaction pathways: the proton transfer forming CH2I−, the formation of IF− via halogen abstraction and first evidence of a [FHI]− product ion [4].
Furthermore we report on the latest results on a study of the transition between predominantly substitution (SN2) driven reactions to elimination (E2) driven ones. This was realized by measuring the energy and angle differential cross sections for reactions between different halide ions (Cl−, F−) and methyl halides of subsequent degree of methylation at multiple collision energies.
[1] J. Mikosch et al., Science 319, 183 (2008) [2] S. Trippel, et al., PRL 110, 163201 (2013) [3] R. Otto et al., Nat. Chem. 4.7 534 (2012) [4] E. Carrascosa et al., submitted to JPC (2015)