Guided ion beam studies of the reactions of Co{sub n}{sup +} (n=1-18) with N{sub 2}: Cobalt cluster mononitride and dinitride bond energies
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112 (United States)
The reactions of Co{sub n}{sup +} (n=1-18) with N{sub 2} are measured as a function of kinetic energy over a range of 0-15 eV in a guided ion beam tandem mass spectrometer. A variety of Co{sub m}{sup +}, Co{sub m}N{sup +}, and Co{sub m}N{sub 2}{sup +} (m{<=}n) product ions are observed, all in endothermic processes, with collision-induced dissociation dominating the products for all clusters. Bond dissociation energies for both cobalt cluster nitrides and dinitrides are derived from threshold analysis of the energy dependence of the endothermic reactions using several different approaches. These values show only a mild dependence on cluster size over the range studied, although the Co{sub 13}{sup +}-N bond energy is relatively weak. The bond energies of Co{sub n}{sup +}-N for larger clusters suggest that a reasonable value for the desorption energy of atomic nitrogen from bulk phase cobalt is 6.3{+-}0.2 eV, which is somewhat lower than the only available value in the literature, an estimate based on the enthalpy of formation of bulk cobalt nitride. The trends in the cobalt nitride thermochemistry are also compared to previously determined metal-metal bond energies, D{sub 0}(Co{sub n}{sup +}-Co), and to D{sub 0}(Fe{sub n}{sup +}-N). Implications for catalytic ammonia production using cobalt versus iron are discussed.
- OSTI ID:
- 21104051
- Journal Information:
- Journal of Chemical Physics, Vol. 128, Issue 19; Other Information: DOI: 10.1063/1.2909978; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AMMONIA
ATOMIC CLUSTERS
BINDING ENERGY
COBALT
DESORPTION
DISSOCIATION
DISSOCIATION ENERGY
ENERGY DEPENDENCE
EV RANGE 01-10
EV RANGE 10-100
FORMATION HEAT
ION BEAMS
ION-MOLECULE COLLISIONS
IRON
KINETIC ENERGY
MASS SPECTROMETERS
NITRIDES
REACTION KINETICS