From localized orbitals to material properties: building classical force fields for nonmetallic condensed matter systems.

The reliability of force fields is one of today's major challenges in atomic scale computer simulations. We show how to generate predictive force fields from ab initio simulations in the condensed phase, using maximally localized Wannier orbitals (WO). We derive separately all interaction terms (electrostatic, exchange repulsion, dispersion, and induction) from these localized WOs. We demonstrate the excellent quality of the resulting force field for two different materials: molten salts and liquid water. This reinforces the usefulness of chemical concepts such as Lewis pairs. The localized WOs provide the missing link between electronic structure in condensed-phase and material properties.