Solubility-consistent force field simulations for aqueous metal carbonate systems using GPUs

Crystallisation of alkaline earth metal carbonates from water is important for biomineralisation and environmental geochemistry. Here large-scale computer simulations are a useful approach to complement experimental studies by providing atomistic insights and even by quantitatively determining the thermodynamics of individual steps. However, this is dependent on the existence of force field models that are sufficiently accurate while being computationally efficient enough to sample complex systems. Here we introduce a revised force field for aqueous alkaline earth metal carbonates that reproduces both the solubilities of the crystalline anhydrous minerals, as well as the hydration free energies of the ions. The model is also designed to run efficiently on GPUs thereby reducing the cost of such simulations. The performance of the revised force field is compared against previous results for important properties relevant to crystallisation, including ion-pairing and mineral-water interfacial structure and dynamics.