Dissociative recombination of the cation and dication of CO2

Dissociative recombination of CO2 ions has been studied at the heavy-ion storage ring ASTRID. Electrons were scattered on both singly and doubly charged positive ions of the molecule, and the absolute cross sections were measured in the energy range of 10-3-101 eV. Thermal rate coefficients of α(CO2+) =(6.5±1.9)x10-7x(300/T[K])0.8 cm3 s-1 and α(CO22+) =(6.2±2.1)x10-7x(300/T[K])0.5 cm3 s-1 were extracted. Furthermore, branching ratios for molecular breakup into neutral product channels have been measured using a grid technique. The branching ratios were measured at ∼0 eV for CO2+, and in the entire energy range from 10-3 eV to 50 eV for CO22+. This measurement reveals pronounced structure in the CO22+ branching ratios