Gas-Phase Reactions of Nickel and Nickel-Rich Oxide Cluster Anions with Nitric Oxide. 2. The Addition of Nitric Oxide, Oxidation of Nickel Clusters, and the Formation of Nitrogen Oxide Anions

A fast flow reactor-quadrupole mass spectrometer coupled with a laser vaporization source is used to study the gas-phase reactions of nickel and nickel oxide cluster anions (Ni x O y -, where x = 1−12 and y = 0, 1, or 2) with nitric oxide. The results indicate that three processes are occurring in the presence of the nickel cluster anions. First, nickel and nickel oxide clusters are oxidized by the reaction with nitric oxide. Second, addition products with these oxides are also formed. Third, nitrogen dioxide and nitrogen trioxide are formed on nickel oxide clusters and subsequently released as anions. Rate constants are reported for the initial reaction occurring between the nickel cluster anions and the nitric oxide, and the reaction rates are compared with reaction rates of the same nickel anion clusters with molecular oxygen. Finally, a comparison of the reaction rates for nickel oxides formed both in the flow tube and in the laser vaporization source are reported. These reactions (previously reported in Part 1) help to provide a better understanding of the formation of free nitrogen oxide anions observed in the current experiments.