NATURE OF EXCITATIONS IN SMALL ALKALI-METAL AND OTHER MIXED CLUSTERS

The contribution of quantum chemical ab - initio studies of optical re sponse in small metal clusters towards understanding of their specific electronic and structural properties has been presented. The role of cluster size, geometry, number of valence electrons and chemical compo sition has been pointed out. It has been shown that an appropriate man y-electron description of excited states for stable cluster structures allows for the quantum molecular interpretation of the absorption spe ctra and other optical probes. The nature of excitations responsible f or characteristic spectroscopic patterns has been discussed.