Hannover 2020 – scientific programme
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MO: Fachverband Molekülphysik
MO 15: MO Poster 3
MO 15.7: Poster
Wednesday, March 11, 2020, 17:00–19:00, Empore Lichthof
Ion-molecule reaction dynamics of atomic oxygen anions with methane — •Atilay Ayasli, Björn Bastian, Tim Michaelsen, Jennifer Meyer, and Roland Wester — Institut für Ionenphysik und Angewandte Physik, Technikerstraße 25/3, 6020 Innsbruck, Austria
We study ion-molecule reactions using a crossed-beam setup with kinematically complete velocity map imaging (VMI) [1]. Currently, we aim to investigate reactive scattering of methane with atomic oxygen anions. The major product channel of the O− + CH4 reaction forms OH− via hydrogen abstraction in an exothermic reaction [4]. Energy dependent experiments ranging from 0.34 eV to 0.63 eV collision energy by Carpenter and Farrar [2] revealed two atomistic mechanisms. The major pathway leads to forward scattering at higher collision energies and a significant backward contribution at the lowest collision energy. Recent theoretical studies suggest a minor reaction pathway forming OCH3− through an endothermic nucleophilic substitution (SN2) process at high collision energies [3]. The second pathway has not been previously observed in experiments, as a high entry barrier of 2.54 eV requires higher collision energies. Here, we report on our progress towards O− + CH4 scattering at higher collision energies to investigate the proposed new reaction pathway.
[1] Wester, Phys. Chem. Chem. Phys. 16, 396 (2014) [2] Carpenter and Farrar, J. Chem. Phys. 106, 5951 (1997) [3] Wang et al., Molecules, 23(10), 2495 (2018) [4] Viggiano et al., J. Chem. Phys. 106, 8455 (1997)