| Description |
Guided ion beam mass spectrometry techniques are used to study the gas-phase ion-molecule reactions of hydrogen and oxygen molecules with second row transition metal ions, M+ = Y+, Ru+, Rh+, Pd+, and Ag+, as well as the reactions of Rh+ and Ag+ with several small alkanes. The cross sections for the observed reactions are measured as a function of kinetic energy of the reactants. The energetics associated with these cross section data are used to derive metal-hydrogen, metal-oxygen, and metal-carbon bond dissociation energies. Analysis of the periodic trends in the metal-hydrogen bond dissociation provides insight into the bonding character of these bonds. Reaction mechanisms are proposed on the basis of isotopic studies in the hydrogen systems or the energy dependence observed for the other systems. The reactivity differences among the various metal systems are understood by using molecular orbital ideas. Additional studies of the reactions of CoO+ with D2 and CH4, FeO+ with D2, and the D2O with Sc+ and Ti+ are mainly designed to probe the potential energy surfaces related to transferring an oxygen atom into the D-D and C-H ?-bonds, and to examine how the reactivity is affected by attaching an oxygen atom to a metal cation, thereby changing the electronic configuration at the metal. |
