I discuss a theoretical description of the resonant x-ray emission spectroscopy (RXES) that is based on the Anderson impurity model. The parameters of the model are determined from material-specific LDA+DMFT calculations. Recently, this approach was shown  to accurately reproduce the L-edge RXES measured in lanthanides . Here, the method is extended to the M-edge spectra in actinide compounds. The same theoretical approach applies also to the x-ray absorption spectra measured in the high-energy-resolution fluorescence-detection mode (HERFD-XAS) . As an example, I investigate the origin of large variations observed among the M-edge HERFD-XAS spectra of uranium compounds where uranium atoms are in the same oxidation state. For instance, both UO3 and torbentite have U atoms in the U(VI) state, but the shape of their x-ray absorption spectra differs quite substantially [4,5].
 J. Kolorenč, Physica B (2017), DOI: 10.1016/j.physb.2017.08.069
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