Interpretation of the accidental predissociation of the E(1) Π state of CO.

A special case of predissociation, known as indirect or accidental predissociation observed in the Rydberg E(1)Π bound state of CO is discussed. We resort to ab initio potentials in order to determine the plausible mechanism for this predissociation. Values of the predissociation width for the valence k(3)Π state of CO, as obtained from Fermi's golden rule, are also reported. The predissociation width obtained for the mixed E(1)Π (v = 1, J = 7) state is 0.033 cm(-1) compared to the experimental value of 0.034 cm(-1). The mixed E - E(') state with J = 28, v = 0 is found to be in near resonance condition with the k(3)Π (v = 4, J = 28) state, thus providing the means to indirect predissociation.