  We study the adsorption of chlorine on the Ag(111) surface with full
potential gradient corrected density functional calculations. When considering
a root3 x root3 R30degree pattern, we find that the fcc hollow is the most
favorable adsorption site. We obtain an Ag-Cl bond length of 2.62 Angstrom
which is intermediate between two controversial experimental results. We
discuss the differences of core level energies and densities of states for the
different adsorption sites. We find the Cl-Ag interaction to be more consistent
with an ionic, rather than covalent, picture of the bonding. In addition, we
compute energetics and related properties of Ag bulk and the clean Ag surface
comparing the local density approximation and the generalized gradient
approximation.
