Surface structural information carried by desorbing reaction products

Recent progress in angle-resolved measurements of desorbing surface reaction products is reviewed. The angular and velocity distributions of desorbing products with hyper-thermal energy deliver the most direct structural information of the product formation site. These distributions yield the orientation of the intermediate species emitting the product as well as the shape of the product formation site. This method works well even when the overall reaction rate is controlled by reactant adsorption or when the interaction between adsorbed species is obscured in kinetic studies under steady-state conditions. For its application, however, information about the reaction mechanism is requisite because the method is directly linked to the reaction itself. Analysis of the product emission in NO reduction on palladium and rhodium as well as the product formation site and its switchover in CO oxidation on platinum is exemplified.