1ST PRINCIPLES CLUSTER CALCULATION OF X-RAY-ABSORPTION SPECTRA OF LA2CUO4

The X-ray absorption spectra are calculated from first principles, taking cluster models of CuO6 and Cu2O11 for La2-xSrxCuO4. The excitation energy for Cu 2p --> 3d, which is calculated by the LDA transition state method, is in good agreement with the recent experimental results. It indicates that (i) the cluster models are suitable for investigating the local properties of the strongly-correlated electronic structure and (ii) some amount of the dopant holes exist in the alg orbital including Cu d3z2-r2.