Dissociative recombination study of HCO$^+$

From accurate quantum chemistry calculations, we have found that the electron collision dynamics of HCO$^+$ is driven by capture into Rydberg states. The Renner-Teller effect is not important for higher Rydberg states. From calculated potentials, the effective quantum numbers are fitted in three dimensions. The full vibrational dynamics of the molecule is considered, and the joint electron-nuclear dynamics is treated using quantum defect theory and a frame transformation approach. Results on autoionization widths for Rydberg states and dissociative recombination cross section are given.