Atomic Physics Seminars

From recent extensive studies on atomic and molecular clusters, it has been shown that their physical and chemical properties alter dramatically as a function of the number of constituent atoms (cluster size). Particularly, clusters of transition-metal elements attract attention because they are expected to possess novel characters in magnetism and catalysis. Since these properties originate from the electronic and geometric structures, it is essentially important to investigate their structures by both experimental and theoretical studies. From the experimental side, the laser spectroscopy of size-selected cluster ions is one of the most powerful means for this purpose. From the theoretical side, on the other hand, recent advances in density-functional theory (DFT) provide powerful tools to search for the optimized geometry and to calculate the electronic structures of small clusters. The theoretical approach to the analysis of the experimental results allows understanding of the size-specific properties of those clusters. On the basis of this strategy we have carried out photoabsorption and photoelectron spectroscopies of small cluster ions of cobalt, vanadium and manganese. Discussion is made by focusing on their magnetic properties. Regarding reactivity, our recent experiments on the reaction of nickel cluster ions with a methanol molecule have revealed reaction processes clearly dependent on the cluster size.