From Clusters To Cluster Complexes*

Adsorption and reactions of molecules on metal clusters have been considered as a fundamental model of catalysis, and attracted much attention both in basic science and industrial areas. Then, the elucidation of their geometric and electronic structures provides a helpful insight into the reaction mechanisms to improve the catalytic properties. Infrared spectra of the nanocatalyst in a helium cluster give much information on the structures related to the reactivity. Recently we have developed a technique to form cluster complexes, Co_m⁺He_n and Co_m⁺NOHe_n, by use of low-energy collision between helium clusters and metal cluster ions. This technique can provide significant amount of the cluster complexes, and we demonstrate the formation and the spectroscopy of the cluster complexes.