STRUCTURES AND ENERGETICS OF V-N(C6H6)(M)(- EVIDENCE FOR A QUINTUPLE-DECKER SANDWICH() CLUSTERS )

V-n(C6H6)(m)(+) cluster ions were produced by laser vaporization/ioniz ation of a vanadium rod into a mixture of helium and benzene. The clus ters with m = n + 1 show strongly enhanced intensities. Ion mobility m easurements and collision-induced dissociation experiments were used t o determine the structure of the different species. Density functional theory calculations using the B-LYP parametrization were performed to provide candidate structures and energetics of these clusters. Compar ison of experimental and theoretical model cross sections indicated th ese clusters have sandwich structures with an alternation of vanadium atoms and benzene molecules. We also found that mass-selected V-n(+) c lusters (n < 5) react with benzene, sequentially adding benzene neutra ls to form terminal ions of formula V-n(C6H6)(n+1)(+). Mobility measur ements on these ions strongly suggest they also have the sandwich stru cture, indicating major structural reorganization occurs when benzene interacts with the vanadium cluster.