Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 50: Oxide and Insulator Surfaces I

O 50.5: Vortrag

Mittwoch, 2. April 2014, 11:30–11:45, WIL A317

A first principles study of halogenated adsorbates on ice — •Michel Bockstedte and Philipp Auburger — Lst. Theor. Festkörperphysik, Universität Erlangen-Nürnberg, 91058 Erlangen

Fluid water, water clusters, and water ice possess the fascinating ability to solvate ions and electrons. 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. Here we investigated the interaction of halogenated hydrocarbons and HCl with prototypical electron traps at the ice surface in the framework of density functional theory (DFT), hybrid DFT, and many body perturbation theory. For the hydrocarbons clear chemical trends across the halogen series, F, Cl, and Br, are found concerning favorable adsorption sites. Depending on the halogen and the electron trap, electron affinity of antibonding adsorbate levels is enhanced. A quenching of electron traps by HCl or Cl⁻, as form during the DEA, is discussed.