15min:

MOHAMMED A. GHARAIBEH AND DENNIS J. CLOUTHIER, Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055.

Laser-induced fluorescence (LIF) and single vibronic level (SVL) emission spectra of the A² _u - X² _g system of ¹²CO₂⁺ and ¹³CO₂⁺ and the A^{2 +} - X² system of N₂O⁺ have been observed. The cations were produced in a pulsed electric discharge jet with a precursor mixture of the corresponding neutral molecule in high pressure argon. The LIF bands of ¹²CO₂⁺ and ¹³CO₂⁺ were 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. SVL emission spectra were also recorded for the ¹³CO₂⁺ ion and the ground state energy levels fitted using the same Renner-Teller model. Due to excited state predissociation, only the low lying vibrational levels have been observed in the LIF spectrum of N₂O⁺. Nitrous oxide cation SVL emission spectra were collected and a complete vibronic analysis of the X² electronic state has been carried out using the Renner-Teller model. Our experimental data provide rigorous tests for future alicab alicinitio potential energy surfaces of these important cations.