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

Exploring Metastable Phases in Cerium-Doped Zirconia: Insights from X-ray Diffraction, Raman, X-ray Absorption, and Luminescence Spectroscopy

dos Santos, L. B. F.; Svitlyk, V.; Richter, S.; Hennig, C.; Müller, K.; Bazarkina, E. F.; Kvashnina, K.; Stumpf, T.; Huittinen, N. M.

Abstract

The ZrO2−CeO2 system is fundamental to various technological applications, yet unresolved questions persist regarding cation miscibility and the occurrence of metastable phases in the Zr1−xCexO2 phase diagram. This work addresses these gaps through a comprehensive investigation of Zr1−xCexO2 compositions with varying cerium concentrations and incorporating Eu3+ as a luminescent probe. Synchrotron powder X-ray diffraction analysis unveiled a miscibility gap between 20 and 50 mol % cerium. Beyond this gap, the formation of solid solutions and multiple crystalline phases was observed, including tetragonal prime (t′) and tetragonal double prime (t″) structures, depending on cerium content. Raman investigations revealed a unique distortion band in all compositions containing the t′ phase. Our high energy resolution fluorescence detected X-ray absorption near edge structure spectroscopy (HERFD-XANES) analysis implies that this feature results from oxygen ion displacement in the t′ structure. Luminescence spectroscopy of the europium environment revealed distinct excitation and emission spectra across the various crystal
phases, enabling unambiguous identification of all metastable phases. These findings highlight the complex polymorphism of the ZrO2−CeO2 system. The ability to precisely control phase composition offers significant potential for optimizing properties for diverse applications, including oxygen sensors, three-way catalysts, and solid oxide fuel cells for clean, sustainable energy generation.

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-41372

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
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
Anne Thielena.thielenAthzdr.de
Dr. Sami Juhani Vasalas.vasalaAthzdr.de