Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 83: Surface Chemistry and Growth
O 83.6: Vortrag
Donnerstag, 19. März 2015, 11:45–12:00, MA 144
The hydrated electron at the ice surface: insight into the dissociative electron attachment to adsorbates — •Philipp Auburger1 and Michel Bockstedte1,2 — 1Lst. Theor. Festkörperphysik, Friedrich-Alexander Universität Erlangen-Nürnberg, 91058 Erlangen, Germany — 2FB Materialwissenschaften & Physik, Universität Salzburg, 5020 Salzburg, Austria
On ice, the solvated electron facilitates electron-induced reactions of adsorbates via dissociative electron attachment (DEA) that for instance take place in atmospheric chemistry. The simultaneous interaction of the electron with the molecule and the ice surface enhances the cross section as compared with the gas phase. The current understanding of the physical mechanisms at work is rather incomplete, in particular a picture on the molecular scale is missing. In this work we address this probleme within the framework of density functional theory, hybrid DFT, and many body perturbation theory. Prototypical surface electron traps, such as orientational disorder, surface vacancies and vacancy clusters are used as a model system. Halogenated hydrocarbons favor adsorption sites that are strong electron traps. Their antibonding molecular orbitals are scattering states with negative electron affinity. By the interaction with the trap states the binding energy is considerably increased. Our results show clear trends across the series F, Cl, and Br.