Contact

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

Department of Molecular Structures


Molecular Structures

Research

The Department of Molecular Structures conducts synchrotron-based research, offering a robust toolkit for scientists investigating materials containing actinides and lanthanides.

Experiments take place at the Rossendorf Beamline of The European Synchrotron (ESRF), in Grenoble (France) which is specifically dedicated to the actinide science and research on radioactive waste disposal. The beamline consists of four experimental stations -XAFS, XES, XRD-1, XRD-2:

  • XAFS station with fluorescence and transmission detection for X-ray Absorption Fine-Structure (XAFS) spectroscopy, including (conventional) X-ray Absorption Near-Edge Structure (XANES) and Extended X-ray absorption fine-structure (EXAFS) spectroscopies
  • XES with a 5-crystal Johann-type spectrometer for high-energy-resolution fluorescence-detection X-ray absorption near-edge spectroscopy (HERFD-XANES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS) measurements.
  • XRD-1 station with a heavy-duty, Eulerian cradle, 6-circle goniometer for (high-resolution) powder X-ray diffraction (PXRD), surface-sensitive crystal truncation rod (CTR) and resonant anomalous X-ray reflectivity (RAXR) measurements
  • XRD-2 station with a Pilatus3 x2M detector stage for single crystal X-ray diffraction (SCXRD) and in situ/in-operando PXRD measurements.

Our research provides detailed insights into the structural and electronic properties of actinide and lanthanide-containing materials across various scientific disciplines, including physics, chemistry, environmental science, and geoscience. We study fundamental electron interactions, bonding properties, probing the local structures and oxidation states of complex systems. Data analysis is performed with the help of electronic structure calculations. 

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.

More about Rossendorf Beamline



Latest publication

The magnetic exciton of EuS revealed by resonant inelastic x-ray scattering

Amidani, L.; Joos, J.; Glatzel, P.; Kolorenc, J.

Abstract

We report the valence-to-core resonant inelastic x-ray scattering (RIXS) of EuS measured at the
L3 edge of Eu. The obtained data reveal two sets of excitations: one set is composed of a hole in the
S 3p bands and an electron excited to extended Eu 5d band states, the other is made up from a hole
in the Eu 4f states and an electron in localized Eu 5d states bound to the 4f hole by its Coulomb
potential. The delocalized excitations arise from the dipole-allowed 5d → 2p emissions, whereas
the localized excitations result from the dipole-forbidden (quadrupole-allowed) 4f → 2p emissions.
Both these emission channels have a comparable intensity thanks to a small number of occupied 5d
states (≈ 0.6) combined with a large number of occupied 4f states (seven). We identify the localized
electron-hole pairs with the “magnetic excitons” suggested in the past as an interpretation of the
sharp features seen in the optical absorption spectra. Our observations provide a direct experimental
evidence of these excitons which has been missing up to now.

  • Physical Review Letters (2025)

Downloads

  • Secondary publication expected from 27.01.2026

Permalink: https://www.hzdr.de/publications/Publ-38715


More publications


Team


Head

NameBld./Office+49 351 260Email
Prof. Dr. Kristina KvashninaROBL/21.6.04+33 476 88 2367

Employees

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
Dr. Elena BazarkinaROBL/14.1.01+33 476 88 4578
Clara Lisa E SilvaROBL/14.1.04+33 476 88 2044
Jörg ExnerROBL/BM20+33 476 88 2372
Dr. Christoph HennigROBL/21.6.02a+33 476 88 2005
Dr. Eleanor Sophia Lawrence Bright+33 476 88 2462
Dr. Damien PrieurROBL/21.6.03+33 476 88 2463
Dr. André Roßberg801/P3162758