CRITICAL PHENOMENA IN PARTICLES OF MESOSCOPIC SIZE

Anomalous optical properties of small silver particles and some silver halides are discussed as displays of critical phenomena due to partic le size decreasing or to their interaction with each other in an ensem ble. Special consideration is given to weak localization of conduction electrons in a small metal particle, to plasmon delocalization in ens emble of metal particles, to the effect of zero- dimensional percolati on in a small dielectric particle, and to the effect of size on the su perionic transition in small AgI particles and thin envelopes.