Coincidence spectra of threshold photoelectrons and ions near the C2Σu+state of N2+

Threshold photoelectrons of N 2 were generated by irradiation with photons of an energy near that of the C 2 Sigma u + state of N 2 + . Synchrotron radiation was used as a light source and the coincidences between threshold electrons and ions were observed. Vibrational levels higher than nu '=3 of the C 2 Sigma u + state were confirmed to predissociate at a considerable rate. The lower vibrational levels of the C 2 Sigma u + state predissociate strongly to the first dissociation limit while the higher vibrational levels predissociate to the second and third limits in addition to the first limit.