Here we report the interpretation of all spectral features of Ce ${\mathit{L}}_3$ x-ray-absorption near-edge structure (XANES) of ${\mathrm{CeO}}_2$ over a 40 eV range. The local partial unoccupied density of states in the initial state and in the fully relaxed final state have been calculated by the full multiple-scattering approach. The wave function of the excited electron in the final states of the Ce ${\mathit{L}}_3$-edge XANES spectrum is found to be determined by the multiple-scattering processes in a large size cluster formed by at least 45 atoms. We predict, in good agreement with the experimental data, the crystal-field splitting of 5d states in the final state ${\mathrm{\Delta }}_{\mathit{f}}$=4.0±0.2 eV and its variation from the initial to the final state. The many-body final states for the 2p→5,ɛd transition, arising from the configuration interaction due to mixing of Ce 4f and O 2p valence orbitals, have been calculated taking into account the crystal-field splitting of the 5,ɛd states and they give a full explanation for the low-energy shoulder on the Ce ${\mathit{L}}_3$ x-ray-absorption spectrum white line that was the object of a long-standing discussion. The origin of the pre-edge peak at about 10 eV below the white line maximum is explained as due to transitions at the bottom of the conduction band.

A combined x-ray-absorption near-edge structure and extended x-ray-absorption fine-structure quantitative analysis, based on fitting procedures of both low- and high-energy ranges, has been carried out at the Cu K edge. This allowed an accurate determination of the structural parameters associated with the first hydration shell of the ${\mathrm{Cu}}^{2+}$ aqua complex. The existence of an average fivefold coordination has been evidenced, ruling out the recently proposed regular pyramidal configuration with five equal Cu-O distances. Our structural results are compared with recent neutron-diffraction data performed by the second-difference isotopic substitution method.

We report the first quantitative analysis of the Fe K-edge polarized x-ray absorption near edge structure of the iron protein carbonmonoxy-myoglobin (MbCO) single crystal and of its cryogenic photoproduct ${\mathrm{Mb}}^{*}\mathrm{CO}$. The CO-Fe-heme local structure has been determined using a novel fitting procedure based on the full multiple scattering approach. The extracted local structure of ${\mathrm{Mb}}^{*}\mathrm{CO}$ includes a Fe-CO distance of $(3.08\pm 0.07)Å$, with a tilting angle between the heme normal and the Fe-C vector of $(37\pm 7)°$, and a bending angle between the Fe-C vector and the C-O bond of $(31\pm 5)°$.