The linearly polarized Cu L3-edge x-ray-absorption near-edge structure (XANES) of Bi2Sr2CaCu208+z has been measured and the spectra are interpreted by the full multiple-scattering approach in real space.The polarized spectra over a range of 20 eV can be predicted in terms of the one-electron dipole (Al =+1)transition Cu 2p~ed, probing the unoccupied d-like (1=2) density of states projected on the Cu site with orbital angular momentum m& =0, 1 in the E~~z spectra, and the mI=2, 1, and 0 in the Elc spectra. The oscillator strength for the dipole allowed transitions (Al = -1) Cu 2p~v s is shown to be a factor of 100 weaker than the 2p~3d transitions. The Coulomb interaction in the final state between the Cu 2p core hole and the excited Cu 3d electron is found to be 5.5 eV forming a bound state below the continuum threshold, the well-known Cu L3 white line. On the contrary, the core hole induces a nearly rigid redshift about 1 eV of the high-energy conduction bands.

The Ag/MgO͑100͒ interface has been studied by EXAFS. At room temperature, in agreement with previous investigations, silver at low coverage is shown to form a two-dimensional layer at the MgO͑100͒ surface. EXAFS data demonstrate that the lattice parameter of the silver overlayer is expanded so as to fit the MgO parameter to give rise to an interface having ͑100͒ Ag ʈ(100) MgO and ͓100͔ Ag ʈ͓100͔ MgO orientation. Interface Ag atoms are atop the oxygen atoms of the MgO͑100͒ surface at a distance of 2.53Ϯ0.05 Å.

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