  It is shown that it is now possible to include van der Waals interactions via
a nonempirical implementation of density functional theory to describe the
correlation energy in electronic structure calculations on infinite systems of
no particular symmetry. The vdW-DF functional [Phys. Rev. Lett. 92, 246401
(2004)] is applied to the adsorption of benzene and naphthalene on an infinite
sheet of graphite, as well as the binding between two graphite sheets.
Comparison with recent thermal desorption data [Phys. Rev. B 69, 535406 (2004)]
shows great promise for the vdW-DF method.
