Gas Phase Chemical Reactions of Transition Metal Clusters

Transition metal clusters are generated by pulsed laser vaporization and nucleation in a continuous gas‐flow reactor. Gaseous reactants are added downstream, and the resulting products expanded into vacuum, collimated into a molecular beam, and analyzed by pulsed laser nonresonant multiphoton ionization and time‐of‐flight mass spectrometry. Oxidation of iron clusters is found to yield iron‐deficient species with the approximate composition Fe 0.9 O. Nickel cluster oxidation gives oxygen‐deficient products having the formula NiO 0.75 . The relation of these results to bulk metal oxidation is discussed. Hydrogenation/deuteration of iron clusters is described, and evidence for H‐D exchange on iron clusters is presented. Reaction of iron clusters with CO is also reported.