ELECTRONIC-STRUCTURE AND PROPERTIES OF THE GROUND-STATE OF COPPER IN SEMICONDUCTING CUPRATES

The spin-polarized discrete variational X(alpha) method is used to cal culate clusters that model the electronic structures of CuO, La2CuO4, and Nd2CuO4. It is shown that in each of the compounds the unoccupied portion of the valence band involves mainly the O2p stares, the contri butions from the Cu3d orbitals being significantly smaller. The effect s of the nature of holes in the valence band and of the structure of t he close environment of copper on the low-energy CuK spectra and the X -ray photoelectron spectra of the above systems are discussed.