  We study deposition dynamics of Na and Na$_2$ on an Ar substrate, both
species neutral as well as charged. The system is modeled by a hierarchical
approach describing the Na valence electrons by time-dependent
density-functional theory while Na core, Ar atoms and their dynamical
polarizability are treated by molecular dynamics. We explore effects of Na
charge and initial kinetic energy of the impinging Na system. We find that
neutral Na is captured into a loosely bound adsorbate state for sufficiently
low impact energy. The charged monomers are more efficiently captured and the
cation Na$^+$ even penetrates the surface layer. For charged dimers, we come to
different final configurations depending on the process, direct deposit of
Na$_2^+$ as a whole, or sequential deposit. In any case, charge dramatically
amplifies the excitation of the matrix, in particular at the side of the Ar
dipoles. The presence of a charge also enhances the binding to the surface and
favours accumulation of larger compounds.
