Photochemistry at nanoparticulate surfaces

Recent developments in the field of photochemistry at nanoparticulate surfaces will be reviewed. Data on laser induced diffusion, desorption and dissociation of molecules adsorbed at supported palladium nanoparticles in the size regime of a few tens to up to a few 10 000 atoms per island will be summarized. Nanosecond as well as femtosecond experiments including quantum state selective monitoring of the energy partitioning within the desorbing molecules will be presented. Interesting effects such as adsorbate induced roughening of the particles after coherent laser excitation will be reported. All phenomena exhibit a strong size dependence for the photochemistry below an average particle size of 80 A and with remarkable changes within the population of different reaction paths below 45 A aggregates. Defects as well as edges and kinks turn out to be important for pinning the electronically excited states