Photostimulated solid state reactions

This article gives a critical review of published results mainly on systems of the type (metal/chalcogenide glass), correlating these with phenomena occurring in (metal/photosensitive substance) systems. It is argued that the striking differences in the reaction curves of different pairs of (metal/photosensitive substance) are due only to the inherently different properties of the products of the 'tarnishing' reaction that occurs in each case. It is emphasized that the driving force of all the phenomena observed is actually this tarnishing reaction which occurs on illumination.