Knowledge Bank

Following work reported at this conference last year and recently $published,1$ we have recorded additional infrared spectra of the $CO2+$ molecular ion by diode laser absorption spectroscopy. These new spectra originate from vibronic levels associated with the excited bending ($\nu 2$) vibration of the ion and are to levels in the $\nu 2=2$ state. Approximately 40 rotation-vibration lines in each of the and $(\mu )2\Pi 3/2,1/2+2\Sigma +$ vibronic bands have been detected and assigned at wavelengths between 19 and $22\mu m$. Many new lines in the $\nu 2$ fundamental bands corresponding to higher retational excitation have also been recorded. These data make $CO2+$ the best documented example of a Renner-Teller interaction in a linear molecule and together with information from the electronic spectrum of the ion, provide a rigorous test of state of the art theory of the effect.