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 th e 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 N b-12(+). They suggest the presence of at least two structural isomers of th ese clusters with one of these being unreactive. The abundance ratios of th e reactive to the unreactive isomers for these three dusters can be determi ned from the kinetic fits to be 1/4, 2/1 and 1/8, respectively. (C) 2000 El sevier Science B.V. All rights reserved.