X-ray photoelectron spectra of the 3s core lines of NiO, CoO, FeO and MnO obtained on high-quality single crystals are interpreted on the basis of an impurity-cluster configuration-interaction model where the exchange and the intra-atomic M-shell charge redistribution energies are evaluated ab initio, Good agreement between the experimental and calculated binding energies and the intensity of the spectral components is obtained. These results clarify the interplay among the charge transfer, exchange and intra-atomic charge redistribution effects on the spectral structure.
