Dissociative recombination of the CO²⁺ dication

Dissociative recombination of a doubly charged molecular ion CO²⁺ has been studied, using a heavy-ion storage ring. There are two final channels of this reaction (C + O⁺ and O + C⁺) that were found to be of about equal strength up to an energy of about 2 eV. The total recombination cross section (yielding C or O) is found to be σ=[2.2/E(eV)]×10^-16 cm² for E<~1 eV, where E is the electron energy. This indicates that the recombination is of the direct type with a curve crossing between the initial state and some repulsive curve of the singly charged ion. Within an accuracy of a factor of 2 we obtain a total recombination rate coefficient α=0.9×10^-7 cm³ s^-1 at T=300 K that is comparable to that of CO⁺.