Multiple-scattering approach to theM-edge x-ray-absorption spectra ofUO2andUCl4

The M-edge x-ray-absorption near-edge spectra was calculated for bulk ${\mathrm{UO}}_2$ and gas-phase ${\mathrm{UCl}}_4$ from a multiple-scattering approach within the muffin-tin–potential approximation. The muffin-tin potential was constructed from the self-consistent relativistic discrete-variational Xα potential. The spectra were interpreted by analyzing the photoelectron-trapping time in different channels inside each atomic sphere. The energy levels of bound states down to the valence levels of the ligands were calculated within the same framework as the continuum in order to set the absolute energy scale. The calculated spectra were compared and found to agree quantitatively with our experimental results.