This proposal addresses the adsorption at S-L interface on oxides, in the presence of appropriate liquids, by Infrared (IR) and UV- Visible (UV-Vis) Total Attenuated Reflection spectroscopy. Particular emphasis will be placed on identification of the species and conditions present at such interfaces. It is planned to examine how a) the reactivity of adsorbed species may be different in the interfacial region, due to excess concentration, steric constraints, and anisotropic polarity; and b) how changes in conformation, tautomerization, oligomerization, or ionization equilibria will affect kinetics.