Dissociative recombination of the ${\mathrm{CO}}^{2+}$ dication

Dissociative recombination of a doubly charged molecular ion ${\mathrm{CO}}^{2+}$ has been studied, using a heavy-ion storage ring. There are two final channels of this reaction $({\mathrm{C}\mathrm{}+\mathrm{}\mathrm{O}}^{+}$ and ${\mathrm{O}\mathrm{}+\mathrm{}\mathrm{C}}^{+})$ 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 $\sigma =[2.2/E(\mathrm{eV}\left)\right]\times {10}^{-16}{\mathrm{cm}}^2$ 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 $\alpha =0.9\mathrm{}\times {10}^{-7}{\mathrm{cm}}^3{\mathrm{s}}^{-1}$ at $T=300\mathrm{}$ K that is comparable to that of ${\mathrm{CO}}^{+}.$