  The method recently developed to include Van der Waals interactions in the
Density Functional Theory by using the Maximally-Localized Wannier functions,
is improved and extended to the case of atoms and fragments weakly bonded
(physisorbed) to metal and semimetal surfaces, thus opening the way to
realistic simulations of surface-physics processes, where Van der Waals
interactions play a key role. Successful applications to the case of Ar on
graphite and on the Al(100) surface, and of the H2 molecule on Al(100) are
presented.
