Auger Spectra and Band Structure of La\u3csub\u3e1.85\u3c/sub\u3eSr\u3csub\u3e0.15\u3c/sub\u3eCuO\u3csub\u3e4\u3c/sub\u3e and La\u3csub\u3e1.85\u3c/sub\u3eBa\u3csub\u3e0.15\u3c/sub\u3eCuO\u3csub\u3e4\u3c/sub\u3e

High-resolution Auger electron spectra of La1.85Sr0.15CuO4 and La1.85Ba0.15CuO4 have been measured. The experimental Auger line shapes of the oxygen KLL and copper L2,3VV transitions are compared with those generated from local-density-approximation linear-muffin-tin-orbital band-structure calculations. An analysis based on this comparison is used to determine the Coulomb parameters Up and Ud of the oxygen and copper atoms, respectively. For this purpose, an extended version of Cini and Sawatzky’s expression for the theoretical Auger line shape is used, taking into account the multiplet structure of the Auger final states and the point symmetry of the oxygen sites. We find Up of approximately 5 and 7 eV for the planar and apical oxygen sites, respectively, and Ud of 7–8 eV for copper. An estimate of the effect of electron correlations on the band structure suggests a decrease of the anisotropy found in Up