Porträt Prof. Dr. Kvashnina, Kristina; FWOS

Prof. Dr. Kristina Kvashnina

Head of Department "Molecular Structures"
Responsible for the BM20 (ROBL) beamline at ESRF
Phone: +33 476 88 2367

Dr. habil. Andreas Scheinost

Molecular Structures

Phone: +33 476 88 2462
+33 6 340 358 18

Department of Molecular Structures

Molecular Structures


  • Synchrotron-based research on the short-range structure, oxidation state and bonding of actinides, using the following methods:
  • EXAFS: Extended X-ray absorption fine-structure spectroscopy to determine the short-range structure of a target element, i.e. the elemental identity, number and radial distance of atoms in its coordination shell and beyond (typically to radial distances of up to 5 A, in well ordered systems even to 10 A).
  • HERFD-XANES: High-energy-resolution fluoresence-detected X-ray absorption near-edge structure spectroscopy to derive oxidation states of the target element
  • XES and RIXS: X-ray emission and resonant inelastic X-ray spectroscopy to derive information on the bonding character (covalent <-> ionic)
  • P-XRD: Powder X-ray diffraction offering much higher resolution or faster speed (in-situ/in-operando) than with lab sources
  • SX-XRD: Single-crystal diffraction
  • Surface-sensitive techniques like CTR (crystal truncation rods) and RAXR (resonant anomalous X-ray reflectivity)  
  • EXAFS, HERFD-XANES, XES and RIXS is not restricted to crystalline solids, but can be applied to a wide range of samples, to derive
    information on e.g. aqueous speciation, complexation with dissolved inorganic ligands like chloride, sulfate or nitrate, complexation with organic ligands like acetate or humic acid, interaction with bacteria and plants, sorption to mineral and rock surfaces for actinides an other metals and metalloids.
  • Due to the high penetration depth of the employed hard X-rays, the methods are suited to study chemical reactions in-situ/in-operando, for instance at very low or high temperatures, under special atmospheres, or under electrochemical potentials.

Latest Publication

Effect of carbon content on electronic structure of uranium carbides

Butorin, S. M.; Bauters, S.; Amidani, L.; Beck, A.; Rossberg, A.; Weiss, S.; Vitova, T.; Kvashnina, K.; Tougait, O.

The electronic structure of UC (x = 0.9, 1.0, 1.1, 2.0) was studied by means of x-ray absorption spectroscopy (XAS) at the C K edge and measurements in the high energy resolution fluorescence detection (HERFD) mode at the U and edges. The full-relativistic density functional theory calculations taking into account the Coulomb interaction U and spin-orbit coupling (DFT+U+SOC) were also performed for UC and UC. While the U HERFD-XAS spectra of the studied samples reveal little difference, the U HERFD-XAS spectra show certain sensitivity to the varying carbon content in uranium carbides. The observed gradual changes in the U HERFD spectra suggest an increase in the C 2p-U 5f charge transfer, which is supported by the orbital population analysis in the DFT+U+SOC calculations, indicating an increase in the U 5f occupancy in UC as compared to that in UC. On the other hand, the density of states at the Fermi level were found to be significantly lower in UC, thus affecting the thermodynamic properties. Both the x-ray spectroscopic data (in particular, the C K XAS measurements) and results of the DFT+U+SOC calculations indicate the importance of taking into account U and SOC for the description of the electronic structure of actinide carbides.

Related publications




Most team members are permanently at the ESRF in Grenoble (France).

ROBL Group Picture 2017/12 ©Copyright: HZDR/Denis Morel

ROBL Group Picture 2017/12

Foto: HZDR/Denis Morel



NameBld./Office+49 351 260Email
Prof. Dr. Kristina KvashninaROBL/21.6.01+33 476 88 2367


NameBld./Office+49 351 260Email
Dr. Lucia AmidaniROBL/14.1.04+33 476 88 1982
Dr. Nils BaumannROBL/21.6.03+33 476 88 2849
Jörg ExnerROBL/BM20+33 476 88 2372
Dr. Christoph HennigROBL/21.6.02a+33 476 88 2005
Damien NaudetROBL/BM20+33 476 88 1941
Dr. Damien PrieurROBL/21.6.04+33 476 88 2849
Dr. André Roßberg801/P3162758
Dr. habil. Andreas ScheinostROBL/21.6.04+33 476 88 2462
+33 6 340 358 18
Thomas Zimmermann801/P2543487