Synopsis
My main research interest lies in the study of
electronic structure using inner-shell spectroscopy. I am
currently leading the scientifc program at an experimenal station
(beamline
ID26) of the European Synchrotron Radiation Facility
(ESRF) in Grenoble/France where
we explore the possibilities of hard X-ray absorption and
emission spectroscopy (XAS-XES). The techniques that we use
include resonant inelastic X-ray scattering (RIXS) or resonant
X-ray emission spectroscopy (RXES).
Many researchers who use RIXS study effects that arise from the
long range order, i.e. in systems that are described in
reciprocal space and where the momentum transfer q is a
crucial parameter (e.g. Ghiringhelli
et al.). Experiments that do not take advantage of the long
range order use other properties of the RIXS process that help to
understand the local electronic structure and this is what I am
mainly interested in.
RIXS finds applications in all fields of natural sciences. For a
general discussion please read our introductions to XAS/XES/RIXS
in
Coord. Chem. Review and
Photosynth. Res.. Some more specific aspects are addressed in
reflections on hard X-ray photon-in/photon-out spectroscopy
and we give some examples for
RIXS in 3d transition metal K pre-edges.
The behaviour of charge transfer excitations in RIXS is nicely
shown in our discussion on how to
identify multi-electron excitations. An example for
interference effects can be found in a demonstration of
spectator and participator transitions in CeO2.
We also developed a little tool to prepare your XAS-XES
experiment that can be used to estimate countrates and where we
discuss possible spectral distortions due to incident beam self
absorption effects (J.
Synchro. Rad.).
Photon-in/photon-out spectroscopy includes:
- Non-resonant X-ray emission (e.g. fluorescence) spectroscopy (XES) (e.g. valence-to-core XES on 3d TM: J. Am. Chem. Soc. 131 13161-13167 (2009))
- Resonant inelastic X-ray scattering (RIXS), resonant X-ray emission spectroscopy (RXES)
- Magnetic circular dichroism (MCD) combined with RIXS
- Ultrafast XES
- Range-extended X-ray absorption fine structure (EXAFS)
- The electronic structure of sulphur:
Inorganic Chemistry (2010) 49 6468-6473
Analytical Chemistry (2009) 81: 6516-6525 - Oxidation of carbon monoxide over Pt nanoparticles:
Journal of the American Chemical Society (2010) 132 2555-2557
Journal of Physical Chemistry B (2006) 110 16162-16164
Angewandte Chemie International Edition (2006) 45 4651-4654 - The Mn4Ca cluster in the oxygen evolving
complex of photosystem II:
Angewandte Chemie-International Edition (2010) 49 800-803
Journal of the American Chemical Society (2004) 126 9946-9959 - Strong K-edge magnetic circular dichroism in Magnetite (Fe3O4):
- Ultra-fast spectroscopy in spin cross-over complexes: