Dynamics of Chemical and Charge-Transfer Reactions of Molecular Dications: III. Beam Scattering and Total Cross Section Data for Processes in the System CO22+ + D2

Chemical reactions and charge-transfer processes in the system CO 2 2+ + D 2 were investigated in crossed-beam scattering experiments. Theoretical calculations of stationary points on the dication potential energy surface (CO 2 D 2 ) 2+ were carried out to complement the experiments. The main ion products identified were CO 2 D +, COD, CO 2 +, CO +, and O + . The relative cross sections for reactions with D 2 (H 2 ) were in the ratio CO 2 +:COD +:CO 2 D + = 100:10:1 and were almost independent of the collision energy over the range 0.5−4 eV (center-of-mass, C.M.). The chemical product CO 2 D + was formed in a nondissociative chemical reaction leading to CO 2 D + + D + through two channels that released different amounts of translational energy via decomposition of intermediates (CO 2 D 2 ) 2+; the high translational energy release channel (peak value at 4 eV) is consistent with the energetics of formation of a D−C-bonded isomer DCO 2 +, which dissociates further to form DCO + + O. The charge-transfer product CO 2 + is formed prevailingly in the excited states A and B; a small amount is also formed by further dissociation of the product CO 2 D + (formed in the low translational energy release channel, presumably in an excited state) to CO 2 + + D. The product CO + results from two different processes: from charge transfer leading to CO 2 + (C 2 Σ g + ) + D 2 + and predissociation of the C state to CO + (X 2 Σ + ) + O( 3 P) and from spontaneous dissociation of the projectile CO 2 2+ (vibrationally excited to its predissociation barrier) to CO + + O + .