Dynamics of chemical and charge-transfer reactions of molecular dications:III. Beam scattering and total cross section data for processes in the system CO22++D-2

Chemical reactions and charge-transfer processes in the system CO22+ + D-2 were investigated in crossed-beam scattering experiments. Theoretical calcu lations of stationary points on the dication potential energy surface (CO2D 2)(2+) were carried out to complement the experiments. The main ion product s identified were CO2D+, COD, CO2+, CO+, and O+. The relative cross section s for reactions with D-2 (H-2) were in the ratio CO2+:COD+:CO2D+ = 100:10:1 and were almost independent of the collision energy over the range 0.5-4 e V (center-of-mass, C.M.). The chemical product CO2D+ was formed in a nondis sociative chemical reaction leading to CO2D+ + D+ through two channels that released different amounts of translational energy via decomposition of in termediates (CO2D2)(2+); the high translational energy release channel (pea k value at 4 eV) is consistent with the energetics of formation of a D-C-bo nded isomer DCO2+, which dissociates further to form DCO+ + O. The charge-t ransfer product CO2+ is formed prevailingly in the excited states A and B; a small amount is also formed by further dissociation of the product CO2D(formed in the low translational energy release channel, presumably in an e xcited state) to CO2+ + D. The product CO+ results from two different proce sses: from charge transfer leading to CO2+(C(2)Sigma(g)(+)) + D-2(+) and pr edissociation of the C state to CO+(X(2)Sigma(+)) + O(P-3) and from spontan eous dissociation of the projectile CO22+ (vibrationally excited to its pre dissociation barrier) to CO+ + O+.