Regensburg 2016 – scientific programme

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O: Fachverband Oberflächenphysik

O 96: Structure of Solid/Liquid Interfaces II

O 96.3: Talk

Friday, March 11, 2016, 11:00–11:15, S052

Ab-initio molecular dynamics simulations on wet alumina/isopropanol solid/liquid interfaces — •Paul Schwarz und Bernd Meyer — Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, FAU Erlangen-Nürnberg

The solid/liquid interface of wet and hydroxylated α-alumina/isopropanol is studied using ab-initio Car-Parrinello molecular dynamics (CPMD) simulations. For the alumina slab three different surface models are taken into account: a termination with a full hydroxyl layer (hyd), an aluminum termination with dissociated water molecules to saturate undercoordinated surface sites (w1) and a third termination with adsorbed water molecules between the OH groups of the w1 structure (w2).

Simulations of the w2 slab show that the additional water molecules induce recombinations events on the surface, leading to the protonation of several OH groups and thereby to the formation of water molecules on top of the aluminum atoms. The occurrence and distribution of these newly formed water molecules is analyzed, as well as proton hopping events on the surface. We show that the proton hopping is energetically driven and correlates with an increased number of H-bonds. Recombination events are also found for the w1 slab after adding isopropanol, whereas the hyd surface remains unchanges. Finally, the influence of the surface termination on the structure of the isopropanol liquid will be discussed.