  Coulomb interaction between electrons on p-orbitals of oxygen atom in
strongly correlated compounds is not negligible, since its value (U_p) has
comparable order of magnitude with the value of Coulomb interaction on
d-orbitals of transition metal atom (U_d). We investigate the effect of taking
into account Coulomb correlations in oxygen p-shell in addition to the
correlations in the transition metal d-shell in frame of the LDA+U method. Our
calculations for NiO, MnO and La2CuO4 show that this additional correction in
general improves the agreement with experimental data for the spectral (energy
gap values, relative position of the main peaks in X-ray photoemission
spectroscopy (XPS) and Bremsstrahlung isohromate spectroscopy (BIS)) and
magnetic properties (magnetic moment values and intersite exchange interaction
parameters values).
