DISSOCIATIVE RECOMBINATION OF CH+

Dissociative recombination of CH+ is studied by using the multichannel quantum defect theory (MQDT). The relevant electronic states were calculated by adopting the self-consistent field (SCF) and the configuration mixing (CM) methods. Particular care was taken to represent correctly the diffuse character of the excited states, especially of the two-electron excited states. The dissociative state coupled with the initial channel was found to cross the lowest potential of CH+ near the left turning point of the first excited vibrational state. We took into account both the p-pi and d-pi partial waves of the incident electron in the MQDT treatment. For this purpose, we modified the MQDT formulation by Giusti so as to fully describe the angular parts. The rate constant obtained is 1.12 x 10(-7) cm3 s-1 at 120 K, which is about one third of the experimental value of Mitchell and McGowan. The contribution of the d-pi wave was found to be comparable to that of the p-pi wave.