  The structure and dynamics of atomic oxygen adsorbed on Ag(410) and Ag(210)
surfaces have been investigated using density functional theory. Our results
show that the adsorption configuration in which O adatoms decorate the upper
side of the (110) steps forming O--Ag--O rows is particularly stable for both
surfaces. On Ag(210), this arrangement is more stable than other configurations
at all the investigated coverages. On Ag(410), adsorption on the terrace and at
the step edge are almost degenerate, the former being slightly preferred at low
coverage while the latter is stabilized by increasing the coverage. These
findings are substantiated by a comparison between the vibrational modes,
calculated within density-functional perturbation theory, and the HREEL
spectrum which has been recently measured in these systems.
