Reactions of homonuclear and heteronuclear group Vb clusters with ethylene: evidence for structural isomers

Reactions of Nb-n(+) and Nbn-1V+ (n=2-15) with C2H4 were investigated in the gas phase under single collision conditions using a Fourier-transform ion cyclotron resonance mass spectrometer. Biexponential decays deviating from simple pseudo-first-order kinetics were observed for Nb-10(+), Nb9V+ and Nb-12(+). They suggest the presence of at least two structural isomers of these clusters with one of these being unreactive. The abundance ratios of the reactive to the unreactive isomers for these three dusters can be determined from the kinetic fits to be 1/4, 2/1 and 1/8, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.