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O: Fachverband Oberflächenphysik

O 40: Solid-Liquid Interfaces

O 40.15: Poster

Dienstag, 17. März 2015, 18:15–21:00, Poster A

Ab-initio molecular dynamics simulations on wet alumina/isopropanol solid/liquid interfaces — •Paul Schwarz and 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. The proper description of liquid isopropanol by our PBE+D2 setup was benchmarked by comparing molecular interaction energies with basis set extrapolated coupled-cluster CCSD(T) results. Furthermore, pair correlation functions and diffusion coefficients from CPMD simulations at different temperatures were compared to experiment. The liquid isopropanol was pre-equilibrated by MD runs with a classical force field. For the alumina slab three different surface models were 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 model with adsorbed water molecules between the OH groups of the w1 structure (w2). In the CPMD simulations of the combined system of solid and liquid phase the recombination of dissociated water molecules is observed, especially in the case of w2. The mechanism and rate of these proton transfer processes is analyzed and we will discuss the influence of the surface model on the structure of the isopropanol liquid.