The Fourth Positive System of Carbon Monoxide Observed in Absorption at High Resolution in the Vacuum Ultraviolet Region

Abstract

The fourth positive system (A `ll-X'~) of carbon monoxide has been observed in absorption at high resolution in the region 1550-1060 A The rotational and vibrational structure of twenty-three bands has been analyzed, viz , the v" = 0 progression for v' = 0-18, 20, 21, and 23 in addition to the (0,1)- band. A detailed assignment of the numerous perturbations in the A ~IJ state is given Most of these per- turbations can easily be attributed to the six known states in the region of the A `H state The observed = 23 level lies above the accepted dissociation limit of CO which indicates a maximum in the potential curve for the A 111 stat