Paper SS1-WeA12
Structure and Dynamics of Liquid Water on Surfaces from Ab Initio Molecular Dynamics: Graphene/Water and Alumina/Water

Wednesday, November 11, 2009, 5:40 pm, Room M

Many important surface phenomena occur under aqueous conditions, where water plays a significant but poorly understood role in interfacial structure and reactivity. Atomic-scale information at solid/water interfaces is notoriously difficult to unravel, and thus simulations are an essential complement to experimental efforts. To date, such simulations typically rely on simple, empirical models for interatomic interactions. However, there is a great deal of ambiguity in the parameterization of these potentials; often they are fitted to bulk properties, and the transferability to complex interfacial systems is unclear. Here, we report atomic-scale simulations of solid/water interfaces via ab initio molecular dynamics, where interatomic interactions are derived on-the-fly from density functional theory. Unlike empirical models, this approach is generally applicable to both bulk and interfacial environments, without input from experiment. Two prototype examples are considered: graphene/water as a model hydrophobic surface, and alumina/water as a model oxide surface. In both cases, a bulk-like liquid water layer at ambient conditions is explicitly included. We examine interfacial structure and dynamics, relate these to spectroscopic observables (infrared spectroscopy, nuclear magnetic resonance). Comparison to predictions from common empirical potentials is given in order to gain insight into when such models fail, and how they can be improved.