Giant Raman scattering of light by molecules adsorbed on the surface of a metal

A review is given of experimental and theoretical work on giant Raman scattering (GRS) by molecules adsorbed on the surface of submicroscopic particles of metals such as silver, gold, and copper. The GRS effect, i.e., the enormous (by a factor of 10') increase in the Raman cross section, is described together with experiments demonstrating the electromagnetic nature of the phenomenon. A model capable of quantitative explanation of the leading features of GRS is put forward.