Surface reaction dynamics and energy partitioning

New approaches to surface reactions are reviewed in comparison with reaction dynamics in the gas phase. These are commonly based on product analysis before energy dissipation, in contrast to the chemical kinetics of surface reactions. Information of energy partitioning during reaction events is requisite to approach to reaction sites. In reactant adsorption, electronic excitations are exemplified to take place, showing non-adiabatic processes. On the other hand, in product desorption, spatial and energy distributions of desorbing products with hyperthermal energy can deliver the most direct structural information of the transition state including active intermediates and product formation sites. Typical analyses are shown in both N2O decomposition and CO oxidation on noble metals.

Product N2 intensity in NO reduction on Rh(1 0 0) versus surface temperature and its angular distribution at 664 K. The inclined emission comes from the decomposition of intermediate N2O. Above about 700 K, the normally directed component due to combinative desorption of nitrogen adatoms predominates.Figure optionsDownload as PowerPoint slide