Department of Molecular Structures

Research

• 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.

Publications

Equipment

• Experiments are performed at the Rossendorf Beamline (BM20-ROBL), at the European Synchrotron Radiation Facility in Grenoble, France

Staff

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