Interfaces in nanostructures: Optical investigations on cluster-matter

The importance of the internal interfaces between structural elements and t heir surroundings for the electronic properties of nanostructured materials is stressed by giving a brief overview of recent optical experiments on se veral different kinds of cluster-matter: (1) The Mie-absorption of silver n anoparticles embedded in various solid matrix materials was used to obtain information about static and dynamic charge transfer in the interlayers and their impact on the plasmon dephasing lifetime. (2) Effects of chemical su rface reactions are demonstrated for silver clusters reacting with oxygen, sulphur and tripenylphosphine. (3) The occurrence of structural and electro nic phase transitions during hydrogenation of yttrium (which is well-known far extended matter) is demonstrated for the first time for clusters. (4) N on-linear optical bi-stability is shown for silver-coated CdS-clusters. Thi s paper was presented at The Fourth international Conference on Nanostructu red Materials, NANO '98, July 1998, Stockholm/Sweden. (C) 2000 Acta Metallu rgica Inc.