It will be argued that in the process of chemical adsorption/desorption on a surface, a molecule with several electrons involved in formation of chemical bonds will always pass extended regions of degeneracy with electronically excited molecular configurations. Such degeneracy allows a process similar to Inverse Electronic Relaxation to take place. Conditions at which the above-mentioned phenomenon can appear as a particularly strong nonadiabatic effect will be examined and links drawn to experimental observations made on several systems as well as to theoretical attempts to account for these effects.
The excited potential energy surface topology, which follows from the consideration, strongly suggests an unexplored previously possibility to initiate elementary chemical transformations on interfaces via electronic excitation of gas-phase molecules. The principal differences of the new approach with the photochemistry within gas phase and/or within molecular aggregates/adsorbates will be emphasized.
Experimental results demonstrating the first surface chemical reaction with electronically excited molecules and a new experimental approach, capable of producing macroscopic fluxes of excited reagents, will be presented. We will report a quantum yield close to 1 for dissociative adsorption of electronically excited SO2 molecules on a surface leading to formation of molecular sulphur
|Period||12. Dec 2007|
|Event title||Evanescent Wave Photocatalysis: null|