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

Abstract

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 HO 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)/HO 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.

Reply to “Molecular mechanics models for the image charge”

“…In fact, our results are quite different from those in Ref. [1], that should be identical. Compare for example the curve "l 5 0.7 Å " (blue triangles) in Figure 1 with that "Pt --R 1 " (also blu triangles) in Figure 1, upper panel, of Ref.…”

“…This strategy does not increase neither the complexity of the model nor its computational cost.In their letter, [1] Steinmann et al present an investigation of image charge interaction between a water molecule and a Pt (111) surface based on the rod model. Chem.…”

“…In their letter, [1] Steinmann et al present an investigation of image charge interaction between a water molecule and a Pt (111) surface based on the rod model. [2] They claimed that such model gives qualitatively incorrect results for specific conditions and concluded that this is due to the asymmetry coded in the original rod model.…”

“…2, the quantity that reproduces the image interaction with the rod model is the interaction free energy F int . [1] Here, we shall calculate F int by thermodynamic integration, without resorting to the linear response approximation, to avoid additional uncertainty. S1), and should therefore be correct for the simulation to be reliable.…”

“…1. [1] A positive (i.e., unfavorable) interaction energies is a particularly puzzling result for a system of charge in front of a polarizable object, no matter how inaccurate the model of the polarization is. [1], that should be identical.…”