FUNDAMENTAL-STUDIES OF THE ENERGETICS AND DYNAMICS OF STATE-SELECTED CO- THE CO+-CH3 AND CO+-I BOND-ENERGIES( REACTING WITH CH3I )

The a3F, a5F, and b3F states of Co+ react with CH3I to form the CoCH3I + adduct as well as CoCH3+ + I and CoI+ + CH3 products. The observed r ates for adduct formation and methyl elimination were found to be stro ngly dependent on the electronic configuration of the metal ion. Under our experimental conditions (10(-5) Torr of CH3I in 1.75 Torr of He), adduct formation is the dominant product for the a3F 3d8 ground state of Co+, with only small amounts of elimination products observed. The 4s3d7 excited states (a5F and b3F) show greatly reduced clustering (d ue to the repulsive 4s electron) and enhanced elimination channels. Th e temperature dependencies of the rate constants were measured and ind icate that all reaction channels, for ground and excited state Co+, in volve the formation of a complex as the initial step in the reaction. By modeling the reaction efficiencies for the elimination channels on the ground-state surface with statistical phase space theory, the Co+- CH3 and Co+-I bond energies were determined to be D-degrees0 = 53.3 +/ - 2 and 50.6 +/- 2 kcal/mol, respectively.