REACTION OF SC+, TI+, AND V+ WITH CO - MC+ AND MO+ BOND-ENERGIES

The reactions of Sc+, Ti+, and V+ with CO are studied as a function of translational energy in a guided-ion-beam tandem mass spectrometer. Formation of both metal-carbide and metal-oxide ions are observed and rationalized by a direct atom abstraction mechanism. At high energies, the ScC+ and ScO+ cross sections exhibit additional features that are unusual but can be explained by an impulsive pairwise mechanism and formation of excited-state product ions, respectively. Thresholds of the reaction cross sections are interpreted to give the 0 K bond energies (in eV) D0 (ScC+) = 3.34 +/- 0.06, D0 (TiC+) = 4.05 +/- 0.24, D0 (VC+) = 3.87 +/- 0.14, D0 (ScO+) = 7.11 +/- 0.08, D0 (TiO+) = 6.88 +/- 0.07, and D0 (VO+) = 5.81 +/- 0.17. Additional studies are used to help verify the bond energy for ScO+ and yield a recommended value of 7.14 +/- 0.11 eV. The nature of the bonding in MO+ and MC+ is discussed and compared for these three metal ions.