Threshold photoelectrons coincidence spectroscopy of N22+ and CO2+ ions Original Research Article

Threshold photoelectrons coincidence (TPEsCO) spectra of the nitrogen and carbon monoxide dications have been recorded with improved resolution (≈ 40 meV) allowing us to clearly resolve the lowert three vibrational progressions in each species. For the nitrogen dication we have identified, for the first time, the 3Σg− state predicted by theory and determined its constants. In the case of the CO dication, we have determined that the ν = 0 level of the 11Σ+ state is almost degenerate with X3Π, ν = 1 and is thus one vibrational quantum lower than previously believed.