High resolution absorption spectrum of CO2between 10 and 14 eV

Abstract

The gas-phase absorption spectra of 12CO2 and 13CO2 between 880 and 2000 A, at a resolution limit of 0·008 A, were recently photographed dy Cossart-Magos et al. Rotational structure observed at 1106 A was then assigned to absorption to the … 1π3 g 3pπ u 3Σ- u Rydberg state. The whole region between 898 and 1145 A is now analysed. Ab initio calculations are carried out to estimate the energy of the lower Rydberg states of the s, p, d and f series converging to [Xtilde] 2Π g CO+ 2. nf transition bands are characterized by sharp features in their rotational contours and assigned from n = 4 to n = 28 and 32, respectively for the limits Ωc = 3/2 and 1/2 in the [Xtilde] 2Π g state of the ion core. A new value of the first ionization potential of CO2 results: 111 201 ± 2 cm-1 (average of the two limits). np transition bands, with the exception of the 1106 A band referred to above, are diffuse, and were assigned by a method based on comparison of experimental and calculated quantum defects plotted against the red...