Photodissociation near a rough metal surface : effect of reaction fields

The modification of the photochemical dissociation rate of molecules in the presence of a rough metal surface is explored. Classical electromagnetic calculations are presented for the photodissociation rate of a point dipole near a rough surface modeled as a hemispheroidal bump on a semi-infinite flat plane. A correction is introduced by accounting for the reaction fields due to the dipole–substrate system radiating photons and coupling to delocalized surface plasmons. The effects of the shape and size of the bump, and the separation of the molecule from the bump on the rate of photodissociation of the molecule, are studied numerically.