Inclusion of Van der Waals Interactions in DFT using Wannier Functions without empirical parameters

We describe a method for including van der Waals (vdW) interactions in Density Functional Theory (DFT) using the Maximally-Localized Wannier functions (MLWFs), which is free from empirical parameters. With respect to the previous DFT/vdW-WF2 version, in the present DFT/vdW-WF2-x approach, the empirical, short-range, damping function is replaced by an estimate of the Pauli exchange repulsion, also obtained by the MLWFs properties. Applications to systems contained in the popular S22 molecular database and to the case of adsorption of Ar on graphite, and Xe and water on graphene, indicate that the new method, besides being more physically founded, also leads to a systematic improvement in the description of systems where vdW interactions play a significant role.