Reaction of tungsten anion clusters with molecular and atomic nitrogen

摘要

Ultraviolet photoelectron spectra for W_nN~-_2(n=1-8) clusters produced by addition of atomic an dmolecular nitrogen on W anion clusters are presented.Evidence is provided that molecular chemisorption of N_2 is more stable than the dissociative one on tungsten anion clusters consisting of eight atoms or less,which is completely different form the results on tungsten bulk surfaces.A general tendency toward molecular chemisorption for small clusters can be explained by reduced charge transfer form the metallic d-orbitals of cluster in contrast to bulk d-orbitals.Comparative studies on chemisorption of atomic and molecular species of diatomic molecules on nanoculausters are expected to provide important information on size-dependent changes of chemical properties of nanoclusters.