Laser induced fluorescence spectroscopy of the jet-cooled carbon dioxide cation (12CO2+ and 13CO2+)

The A approximate to (2)Pi(u)-X approximate to (2)Pi(g) band systems of jet-cooled (CO2+)-C-12 and (CO2+)-C-13 have been recorded by laser-induced fluorescence (LIF) techniques. Very intense, vibrationally cold expansions of these cations have been obtained using a pulsed electric discharge jet with a precursor mixture of carbon dioxide or C-13 labeled CO2 in high pressure argon. The LIF bands have been partially rotationally analyzed to obtain band origins which yielded an accurate measure of the excited state vibronic energy levels. The energy levels of both isotopologues were fitted with a Renner-Teller model that included spin-orbit coupling, Fermi resonance and anharmonic terms. Single vibronic level emission spectra were also recorded for the (CO2+)-C-13 ion and the ground state energy levels fitted using the same Renner-Teller model. The isotope relations have been used to test the validity of the derived parameters. The results give a through description of the vibronic energy levels in the ground and first excited electronic states of the carbon dioxide cation.