Experimental observation of autoionizing transitions from the decay of the 1,3Πu inner-shell excited states of carbon dioxide

Inner-shell excited states of carbon dioxide have been studied in a high-resolution electron impact experiment. The excited states (1s)−1(2pπu) 1,3Πu have been observed as a function of impact energy via their decay, by ejection of an electron, to an ionic state of the molecule. A shift in the energies of these ejected electrons has been observed and is explained in terms of a post collision interaction effect. The relative cross section for the formation of the CO2+ (A2Πu) final ionic state, via the decay of these inner-shell excited states, has been measured.