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Crystal-field states of UO<sub>2</sub> probed by directional dependence of nonresonant inelastic x-ray scattering

ORAL

Abstract

Core-level nonresonant inelastic x-ray scattering (NIXS) [1-3], also called x-ray Raman scattering, has been performed on single crystals of UO2 to study the directional dependence of higher-order multipole scattering from the uranium O4,5 edges (90–110 eV). By comparing the experimental results with theoretical calculations the symmetry of the ground state is confirmed directly as the crystal-field Γ5 triplet state within the J = 4 manifold [4] as had been suggested by inelastic neutron scattering [5]. The results demonstrate that the directional dichroism of the NIXS spectra is sensitive to the CF strength and establish NIXS as a tool for probing crystal-field interactions quantitatively.

[1] M.W. Haverkort et al., Phys. Rev. Lett. 99 257401 (2007)
[2] R. Caciuffo et al., Phys. Rev. B 81 195104 (2010)
[3] M. Sundermann et al., PNAS 113 13989 (2016)
[4] M. Sundermann et al., Phys. Rev. B 98 205108 (2018)
[5] G. Amoretti et al., Phys. Rev. B 40 1856 (1989)

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Presenters

  • Martin Sundermann

    Institute of Physics II, University of Cologne, Physics 2, University of Cologne, Germany, Max Planck Institute for Chemical Physics of Solids

Authors

  • Martin Sundermann

    Institute of Physics II, University of Cologne, Physics 2, University of Cologne, Germany, Max Planck Institute for Chemical Physics of Solids

  • Gerrit Van der Laan

    Diamond Light Source, Magnetic Spectroscopy Group, Diamond Light Source

  • Andrea Severing

    Institute of Physics II, University of Cologne, Physics 2, University of Cologne, Germany, University of Cologne

  • Laura Simonelli

    ALBA Synchrotron Light Source

  • Gerard H Lander

    European Commission, Joint Research Centre (JRC)

  • Maurits Haverkort

    Institute for Theoretical Physics, Heidelberg University, Institute for theoretical physics, Institute of Theoretical Physics, University of Heidelberg, Theoretical Physics, Heidelberg University, Germany, Heidelberg University

  • Roberto Caciuffo

    DG Joint Research Centre, Directorate G-Nuclear Safety and Security, Karlsruhe, Germany, European Commission, Joint Research Centre (JRC)