Multiple ionization upon K-shell photoabsorption of the CO and N₂ molecules

The spectra of multiple ionization of CO and N2 in the gas phase in the region of the K-shell ionization thresholds of C and N are studied theoretically. The processes of additional excitation/ionization from 1π and 5σ-shells are included. The effects of many-electron correlations on the extention of multiplet structure for some configurations of multiple excitations is studied. Absolute values of photoabsorption cross sections are calculated in some of the channels of multiple ionization.