THE NONMETAL-METAL TRANSITION OF BI2SR2CA1-XYXCU2O8-X-RAY EMISSION-SPECTROSCOPY(DELTA STUDIED BY SOFT)

Cu L(alpha,beta) and O K(alpha) x-ray emission spectra and the measure ments of the occupancy of Cu 3d orbitals in Bi2Sr2Ca1-xYxCu2O8+delta a re presented. No appreciable change in the valency of Cu is found with increasing x. In contrast to La2-ySryCuO4 and YBa2Cu3O6+y, when going from non-metal to metal, the high-energy shift of O K(alpha) band, ca used by redistribution of the O 2p states of the apical oxygen atoms, is not observed. The valence states of Cu and O do not essentially red istribute due to Ca doping and the p-d energy separation does not chan ge.