Direct dissociative recombination of HCO⁺ via the core-excited doublet and the lowest quartet states

The dissociative recombination of HCO + up to 1 eV collision energy is studied. New calculations for several core-excited HCO states provide improved potential energy surfaces crossing the HCO + ground state surface in the vicinity of its equilibrium geometry. Wave packet analysis leads to significantly higher contributions of the direct mechanism to the cross section for electron energy ε < 0.7 eV than according to earlier studies [Larson et al. , Phys. Rev. A , 2012, 85 , 042702]. The limit H + CO(a 3 Π) is found to be the most probable exit channel. We discuss the improved agreement of theory with the latest experiments [Hamberg et al. , J. Phys. Chem. , 2014, 118 , 6034] resulting from combination with the most recent calculations of the indirect process [Fonseca dos Santos et al., J. Chem. Phys. , 2014, 140 , 164308]. For the lowest quartet surfaces some vibrational states and their population and depopulation (mediated by spin-orbit coupling) are examined.