Microcluster Physics

This book aims at providing graduate students and researchers with funda- mental knowledge indispensable for entering the new field of "e;microclus- 3 ters"e;. Microclusters consisting of 10 to 10 atoms exhibit neither the pro- perties of the corresponding bulk nor those of the corresponding molecule of a few atoms. The microclusters may be considered to form a new phase of materials lying between macroscopic solids and microscopic particles such as atoms and molecules, showing both macroscopic and microscopic features. However, research into such"e;a riew phase has been left untouched until recent years by the development of the quantum theory of matter. The microscopic features of microclusters were first revealed by ob- serving anomalies of the mass spectrum of a Na cluster beam at specific sizes, called magic numbers. Then it was experimentally confirmed that the magic numbers come from the shell structure of valence electrons. Being stimulated by these epoch-making findings in metal microclusters and aided by progress of the experimental techniques producing relatively dense, non- interacting micro clusters of various sizes in the form of micro cluster beams, the research field of microclusters has developed rapidly in these 5 to 7 years. The progress is also due to the improvement of computers and com- putational techniques, which have made it possible to perform ab initio cal- culations of the atomic and electronic structure of smaller microclusters, as well as to carry out computer simulations of their dynamics.