Ab Initio Molecular Dynamics Simulations of (101) Surfaces of Potassium Dihydrogenphosphate.

We present an ab initio molecular dynamics study of bare and hydrated (101) surfaces of KDP. We examine the dynamical nature of the hydrogen bonding in the high and low temperature phases of bulk KDP and find evidence to support the theory that hydrogen atoms oscillate between two off-center positions in the high-temperature phase. We report the translational relaxation of the surface species on the (101) surface and find good agreement with experimental results, particularly with reference to the direction of the relaxation. We find a strongly hydrogen bound water layer close to the KDP surface, comparing closely to a highly ordered water layer observed experimentally. Overall, there is good agreement with the results of nanoscale experimental studies, demonstrating the effectiveness of ab initio molecular dynamics calculations at simulating bulk and surface properties.