Chemistry of (and on) transition metal cluster : a Fourier transform ion cyclotron resonance study of the reaction of niobium cluster cations with nitric oxide

The reactions of niobium cluster cations, Nb-n(+) (n = 2-19), with nitric oxide have been investigated using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR). The overall reaction rate constants are found to be in reasonable agreement with collision rates calculated using the surface charge capture model. The dominant reaction for small clusters (n 11) is sequential NO chemisorption. Clusters n = 9, 10 exhibit both extremes of behaviour and are the only clusters upon which there is evidence of NO decomposition with N-2 loss observed whenever multiple NO molecules are co-adsorbed. The rate constants for each process have been determined as a function of cluster size