Interaction of water with an oxygenated Ag(111) surface leads to an en
hancement of the surface restructuring and an activated formation of h
ydroxyl groups (OH) located stably on the surface and incorporated in
the subsurface region, as evidenced by means of reflection electron mi
croscopy (REM) and in situ Raman spectroscopy. Dehydroxylation of OHad
s at elevated temperatures releases the strongly bound oxygen species
labelled O-gamma at the surface, and offers an alternative to the ener
getically less favorable pathway for the direct formation of the O-gam
ma species from molecular oxygen.