Spectroscopic studies of silver atoms and clusters.

Conjoint ESR and optical studies of silver atoms (Ag0) and silver clusters formed in aqueous and alcoholic matrices resulted in the unequivocal assignments of optical absorptions to a range of Ag0 solvates and to the molecular clusters Ag+2 and Ag43+. ESR studies of un-irradiated silver halides revealed the presence of at least two instrinsic centres which might act as the special sites at which latent images are formed during the primary photographic process. On irradiation, these materials exhibited additional signals which were thought to be CESR resonances associated with pseudo- molecular silver particles, Ag0n. The size of these centres is uncertain. The data suggests that they consist of more than 5-6 atoms and are smaller than 45A. They were shown to be likely candidates for photographic latent images as a result of a series of photographic/ESR crossover experiments.