Production of cluster complexes by cluster-cluster collisions-incorporation of a size-selected cobalt dimer ion into a neutral argon cluster

Cluster-cluster collision is one of the methods to produce multi-element cluster complexes, in which the mechanism of coalescence is not clear. We have built an apparatus to study the low-energy collisions between a size-selected metal cluster ion and a neutral molecular cluster by using a merging-beam technique in a pulsed mode. By use of this apparatus, we demonstrate the production of the cluster complexes in the collision of a cobalt dimer ion with a neutral argon cluster as an example. In this collision, the cluster complexes, Co2+Arn (n = 1-30), are observed and the size distribution is dependent on the relative velocity. The production efficiency of the cluster complexes is shown as a function of the relative velocity of the collision, and the incorporation process is explained on the basis of the electrostatic interaction and the hard-sphere interaction below and above the relative velocity of 200 m s(-1), respectively.