  A new implementation is proposed 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 method, 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 an Ar atom interacting with graphite, and
comparison with reference data, indicate that the new method, besides being
more physically founded, also leads to a systematic improvement in the
description of vdW-bonded systems.
