Guided ion beam studies of the reactions of Crn+ (n=2–14) with D2: cluster–deuteride bond energies as a chemical probe of cluster electronic structure Original Research Article

The kinetic energy dependencies of the reactions of chromium cluster cations, Crn+ (n=2–14), with D2 are studied in a guided ion beam mass spectrometer. The observed products are CrnD+ (n=2–14) and CrnD2+ (n=6–14). All reactions are observed to exhibit thresholds, except for formation of the dideuteride product for Crn+ (n=6–8). Threshold analyses of the endothermic reactions reveal binding energies for the first deuterium atom to the cluster ions as a function of cluster size. The Crn+–D bond energies are compared to previously determined metal–metal bond energies, D0(Crn+–Cr). The bond energies of Crn+–D exhibit odd–even oscillations with n that parallel those of Crn+–Cr. These trends support our earlier suggestion that bonding in Crn+ clusters, at least for n=2–11, are governed by electronic factors.