9400526 Madix The determination of the relationship between the spatial organization of adsorbed layers and the kinetic description of their reactivity is the goal of this research project supported by the Analytical and Surface Chemistry Program. Temperature dependent scanning tunneling microscopy will be used to isolate, stabilize and image reaction intermediates. This structural information will then be correlated with kinetic studies of these reactions, using thermal desorption spectroscopy as the primary probe of reaction kinetics. Several reaction systems will be investigated, including the oxidation of Cu(110), the desorption of oxygen from Pt(100), the formation of carbonate on Ag(110), and the decomposition of formates and alkoxides on copper surfaces. Each of these systems either shows unusual reaction kinetics or evidence of interesting structural variations in the reacting overlayers. %%% The connection between overlayer ordering and kinetic processes in surface reactions is a relatively unexplored area of surface chemistry. The work of this project will impact on our understanding of the connection between overlayer ordering and surface reactivity, and may have important implications for reactions in organized media well beyond the individual surface reactions to be studied. ***