Copper L-edge spectra: multiplet vs. multiple scattering theory

Cu L2,3-edge X-ray absorption spectra of the orthorhombic La2CuO4 have been investigated using the multiplet method and the multiple scattering theory. We found that d states of Cu2+ are not localized and both long- and medium- range atoms contribute to the L2,3 edge spectrum, i.e., the transition from 2p electrons to partial and local empty 3d states. The behaviour is different from that observed in many other transition metals in which localized d states are merely influenced by the crystal field with a strong spin-orbit interaction.