Genetic Algorithm Workflow for Parameterization of a Water Model Using the Vashishta Force Field

Water participates in countless processes on Earth, and the properties of mineral surfaces can be drastically changed in the presence of water. For example, the fracture toughness of silica glass is reduced by 25% for water-filled cracks than for dry cracks [Geophys. Res.: Solid Earth 2018, 123, 9341–9354]. An accurate description of water is therefore essential for modeling the behavior of minerals in aqueous environments and, in particular, for modeling dynamic processes such as fracture, where the mechanical response of water may play an important role. On the molecular scale, molecular dynamics simulations with empirical force field methods provide a way to study large molecular systems at a relatively low computational cost. Many water models have been developed previously; however, a computationally cheap water model capable of describing reactions with minerals is lacking. Here, we present a parametrization of the water potential using the Vashishta potential form [Phys. Rev. B 1990, 41, 12197–12209]. For this 3-point water model, we obtain good agreement with experimental transport and liquid–vapor properties. Importantly, the Vashishta form opens up compatibility with existing silica glass models, thus enabling the simulation of mineral–water interactions.