Quasi-band electronic structure of V_n(benzene)_n+1 clusters

Photoionization efficiency (PIE) curves were measured for sandwich vanadium-benzene clusters, V_n(benzene)_n+1 (n = 1-5), which were produced by the reaction of laser-vaporized vanadium atoms with benzene vapor. A two-rod laser vaporization source was used for enhancing the production of the larger clusters. The second lowest ionization energies of the sandwich clusters were probed experimentally for the first time. The PIE curves of the sandwich clusters clearly present evidence that the clusters take a quasi-band electronic structure which results from a one-dimensional sandwich structure.