This Brief Report presents an improved theoretical description of dissociative recombination of ${\text{HCO}}^{+}$ and ${\text{DCO}}^{+}$ ions with a low-energy electron. In a previous theoretical study [Mikhailov et al., Phys. Rev. A 74, 032707 (2006)] on ${\text{HCO}}^{+}$, 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 $\left(<0.1\text{eV}\right)$ but somewhat larger at higher $\left(>0.1\text{eV}\right)$ 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.

• Received 23 April 2008

DOI:https://doi.org/10.1103/PhysRevA.77.064703