Classical and quantum-mechanical calculations of HCO++e→CO(υ)+H

It has been suggested that interstellar CO produced in the dissociative recombination between HCO+ and electrons can be detected via infrared emission from excited vibrational levels. Using classical and quantum mechanical equations of motion, we have calculated the distribution of CO product vibrational states for the dissociative recombination reaction between HCO+ and electrons. We have assumed the dissociation to occur along a purely linear geometry. The CO vibrational distribution has been calculated for two electronic states: (1) the ground X (1) Sigma(+) state and (2) the excited a 3 Pi state. For the X state, we have used a newly calculated ab initio potential surface for the dissociation of HCO. Results for the a state can be compared with the results of experimental work by Adams and collaborators. Our results show that in general vibrational excitation of the CO product is not large, so that detection of infrared emission from interstellar clouds will not be facile.