Theoretical rate of dissociative recombination of HCO⁺ and DCO⁺ ions

The article presents an improved theoretical description of dissociative recombination of HCO$^+$ and DCO$^+$ ions with a low energy electron. In the previous theoretical study (Phys. Rev. A {\bf 74}, 032707) on HCO$^+$, the vibrational motion along the CO coordinate was neglected. Here, all vibrational degrees of freedom, including the CO stretch coordinate, are taken into account. The theoretical dissociative recombination cross-section obtained is similar to the previous theoretical result at low collision energies ($<$0.1 eV) but somewhat larger at higher ($>$0.1 eV) energies. Therefore, the present study suggests that motion along the CO coordinate does not play a significant role in the process at low collision energies. The theoretical cross-section is still approximately 2-3 times lower than the data from a recent merged-beam experiment.