Theory of Dissociative Recombination of linear triatomic ions with permanent dipole moment: Study of HCO$^{+}$*

Dissociative recombination of HCO$^{+}$ ions in collisions with low energy electrons has been extensively studied in theory and experiment. Despite recent improvement in the theory, the theoretical calculations and experimental results are still different by about a factor of 2-3. The most recent theoretical approach used to describe the process of dissociative dissociation included all degrees of freedom of HCO$^{+}$ ion, as well as the Renner-Teller effect, which is responsible in HCO$^+$ for the large probability to capture the incident electron. It is also well known that the HCO$^{+}$ ion has a considerable permanent dipole moment ( D$\approx$4 Debye), which could not be taken into account in a standard quantum defect theory approach. In the present study, we explicitly included the effect of the permanent dipole on dynamics of the incident electron using the generalized quantum defect theory and present the new results obtained for the cross section. To our knowledge it is the first application of the generalized quantum defect theory to dissociative recombination of molecular ions.