Force Field for Water over Pt(111): Development, Assessment, and Comparison

Metal/water
interfaces are key in many natural and industrial processes,
such as corrosion, atmospheric, or environmental chemistry. Even today,
the only practical approach to simulate large interfaces between a
metal and water is to perform force-field simulations. In this work,
we propose a novel force field, GAL17, to describe the interaction
of water and a Pt(111) surface. GAL17 builds on three terms: (i) a
standard Lennard-Jones potential for the bonding interaction between
the surface and water, (ii) a Gaussian term to improve the surface
corrugation, and (iii) two terms describing the angular dependence
of the interaction energy. The 12 parameters of this force field are
fitted against a set of 210 adsorption geometries of water on Pt(111).
The performance of GAL17 is compared to several other approaches that
have not been validated against extensive first-principles computations
yet. Their respective accuracy is evaluated on an extended set of
802 adsorption geometries of H2O on Pt(111), 52 geometries
derived from icelike layers, and an MD simulation of an interface
between a c(4 × 6) Pt(111) surface and a water layer of 14 Å
thickness. The newly developed GAL17 force field provides a significant
improvement over previously existing force fields for Pt(111)/H2O interactions. Its well-balanced performance suggests that
it is an ideal candidate to generate relevant geometries for the metal/water
interface, paving the way to a representative sampling of the equilibrium
distribution at the interface and to predict solvation free energies
at the solid/liquid interface.