Molecular Dynamics of the Water-gold Interface including Metal Polarizability Effects in the Classical Force Field

Solid-liquid interfaces are of growing interest to basic science and technology. The water-gold interface has received much attention due to its applications in catalysis and biotechnology. The need of including biomolecular and ionic species in the aqueous environment within atomistic simulations necessitates the accurate inclusion of charge and fluctuations effects of the liquids [Small 12, 2395 (2016)]. The formed interfaces are complex due to the interplay of van der Waals (vdW) interactions, covalent bonds, and image-charge effects due to the highly polarizable surface. Using a classical Drude-oscillator model [JCP 119, 3025 (2003)], we present a force field for the gold-water interface which includes image-charge effects induced in the metal surface. Our parametrization is based on calculations of a single molecule/monolayer of water using vdW-corrected density-functional theory [PRL 108, 146103 (2012)] that includes the many-body collective response of the substrate electrons in the vdW interaction coefficients. We show that this methodology yields a consistent connection between the induced polarizability effects in the surface and the vdW interaction between water molecules and the surface when compared to available literature.