Extending the applicability of popular force fields for describing water/metal interfaces: application to water/Pd(111)

We propose a new method for constructing a polarizable classical force field using data obtained from QM and QM/MM calculations to account for the charge redistribution at the water/metal interface. The induced charge effects are described by adding dipoles to the system topology following the Rod Model (Iori, F, et al J. Comput. Chem.2009, 30, 1465). Furthermore, the force field uses the TIP3P water model, and its functional form is compatible with popular force fields such as AMBER, CHARMM, GROMOS, OPLS-AA, CVFF and IFF. The proposed model was evaluated and validated for water/Pd(111) systems. We tuned the model parameters to reproduce a few critical water/Pd(111) geometries and energies obtained from DFT calculations using both PBE and a non-local van der Waals xc-functional. Our model can reproduce the hexagonal ice layer for the Pd(111)/water systems typically present in low-temperature experiments, in agreement with information available from the literature. Additionally, the model can also reproduce the experimental metal-water interfacial tension at room temperature.