The collision-induced dissociation (CID) of VO+ by rare gases has been studied by using a guided ion beam tandem mass spectrometer. CID by xenon yields @(V+-O) = 6.00 f 0.35 eV, in excellent agreement with a value derived from the literature. However, when the collision gas is Ne, Ar, or Kr, CID is inefficient until 1.0 h 0.2 eV above the thermodynamic threshold. Possible origins for this behavior are discussed. Production of vanadium-rare gas molecular ions is observed in the Ar, Kr, and Xe systems. No reactions, including CID, are observed when helium is the collision gas. In light of this discussion, the utility of threshold CID measurements as a means of determining bond dissociation energies is assessed. IntroductionInterest in gas-phase ionic transition-metal species is very keen as evidenced by a number of recent experimental' and theoretical studies2 In this work, we are interested in whether low-energy collision-induced dissociation (CID) can be used to measure the bond dissociation energies of some of these novel species. Relatively few studies of this application of CID can be found in the literature., In contrast, the use of high-energy CID to find structures of molecules (primarily organic and organ~metallic)~

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Articles you may be interested in Classification of metal-oxide bonded interactions based on local potential-and kinetic-energy densitiesReactions of Ca + , Zn + and all first-row atomic transition metal ions with O 2 are studied using guided ion beam techniques. While reactions of the ground states of Sc +, Ti + , and Y+ are exothermic, the remaining metal ions react with O 2 in endothermic processes. Analyses of these endothermic reactions provide new determinations of the M+ -0 bond energies for these eight elements. Source conditions are varied such that the contributions of excited states of the metal ions can be explicitly considered for Mn + , Co +, Ni + , and Cu +. Results (in e Y) at 0 K areDo(Ca+ -0) = 3.57 ± 0.05, DO(Cr+ -0) = 3.72 ± 0.12, DO(Mn+ -0) = 2.95 ± 0.13, DO(Fe+ -0) = 3.53 ± 0.06 (reported previously), DO(Co+ -0) = 3.32 ± 0.06, DO(Ni+-O) = 2.74 ±0.07,Do(Cu+-O) = 1.62±0.15,andDo(Zn+-O) = 1.65±0.12. These values along with literature data for neutral metal oxide bond energies and ionization energies are critically evaluated. Periodic trends in the ionic metal oxide bond energies are compared with those of the neutral metal oxides and those of other related molecules.

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