The Rh(110) surface was investigated using reflectance anisotropy spec
troscopy (RAS). This optical method is shown to be sensitive to adsorb
ate-induced reconstructions of the Rh(110) metal surface. The reflecti
on anisotropy can be used to monitor adsorption/desorption cycles of o
xygen. The results are interpreted using the known substrate geometry
of nitrogen-and oxygen-induced reconstructions of Rh(110). The technol
ogical relevance of RAS is discussed.