Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 18: f-Electron Systems and Heavy Fermions II

TT 18.9: Talk

Monday, March 12, 2018, 17:15–17:30, H 3005

Theoretical Modeling of Resonant X-Ray Emission Spectra at the Actinide M_4,5 Edges — •Jindrich Kolorenc — Institute of Physics, The Czech Academy of Sciences, Prague, Czech Republic

I discuss a theoretical description of the resonant x-ray emission spectra (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 [1] to accurately reproduce the L-edge RXES measured in lanthanides [2]. 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) [3]. As an example, I investigate the origin of large variations observed among the M-edge HERFD-XAS spectra of several 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
J. A. Bradley et al., Phys. Rev. B 85, 100102 (2012).
K. Hämäläinen et al., Phys. Rev. Lett. 67, 2850 (1991).
Y. Podkovyrina et al., J. Phys.: Conf. Ser. 712, 012092 (2016).
K. O. Kvashnina, Y. O. Kvashnin, S. M. Butorin, J. Electron. Spectrosc. Relat. Phenom. 194, 27 (2014).