Clustering dynamics of the metal-benzene sandwich complex: The role of microscopic structure of the solute in the Bis(eta(6)-benzene)chromium center dot Ar-n clusters (n=1-15)

Abstract

Ar clustering dynamics around the metal-benzene sandwich complex, bis(eta(6)-benzene)chromium: Cr(Bz)2, is found to occur in two distinct regimes. The shift of the ionization potential (IP) upon the addition of Ar is measured to be 151 cm(-1), and it is constant until the number of Ar solvents (n) becomes 6. The IP shift per Ar is found to be suddenly decreased to 82 cm(-1) for the clusters of n = 7-12. The cluster distribution indicates that the n = 6 cluster is most populated in the molecular beam. These experimental findings with the aid of ab initio calculation indicate that the first six Ar solvent molecules are attached to top and bottom of Cr(Bz)(2) to give the robust structure for the Cr(Bz)(2)-Ar-6 cluster whereas the next six Ar molecules are gathered on the side of the solute core to give the highly symmetric structure of the Cr(Bz)(2)-Ar-12 cluster.