2h-1p CI calculations of the complete valence shell ionization potentials and spectral intensities have been performed for acrolein, propynal, s-tetrazine, pyrazine, bis (pgreco-allyl)nickel and nickel chloride, with a DZ basis set. The reduction of the virtual space to the valence or the p-greco space by means of a projection scheme has been tested and found very satisfactory. A complete reproduction of the strong many-body effects present in these systems is observed, in good agreement with the experimental data and the results of previous 2ph-TDA calculations for all molecules except bis (pgreco-allyl) nickel. A new correlation effect appears in the latter molecule, which causes disagreement with the 2ph_TDA results and an unsatisfactory reproduction of the experimental spectrum.
