Cluster Models for Surface and Bulk Phenomena

In the last few years the above authors have undertaken a collaborative study of the physical and chemical properties of high-nuclearity metal cluster compounds. The collaboration was sponsored by the European Economic Community “Stimulation Action” program. In the course of these studies it has become evident that this interesting class of materials may indeed be viewed as model systems for monodisperse small metal particles, embedded in a dielectric solid. The metal cluster compounds consist of (neutral or ionic) macromolecules, each macromelecule being composed of a core of a certain number (n) of metal atoms, the core being surrounded by a shell of ligands. Since these are chemical compounds, a given compound contains macromolecules of one and the same type, and thus an assembly of identical metal cores. Consequently, the solid formed can be described as a macroscopically large sample of identical metal particles, mutually separated by the ligand shells, which provide an effective means of “chemical stabilization”.