Berlin 2001 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 9: New Methods
CPP 9.1: Talk
Wednesday, April 4, 2001, 15:45–16:05, 112
Imaging of oxidation states in bulk material with synchrotron radiation — •Christoph Rau1, Andrea Somogyi2, Alexandre Simionovici1, Timm Weitkamp1, Freddy Adams2, and Anatoly Snigirev1 — 1ESRF, 6 rue Jules Horowitz, BP 220, F-38043 Grenoble CEDEX, France — 2University of Antwerp, Department of Chemistry, Universiteitsplein 1, B-2610 Wilrijk-Antwerp, Belgium
The use of synchrotron radiation gives access to numerous chemical and physical properties of bulk samples, being in particular transparent to hard X-rays. One of the well established methods in this field of research is the X-ray absorption near-edge spectroscopy (XANES). By scanning the X-ray energy around the absorption edge of an element one can obtain information about the oxidation state of the probed atoms. Until now this technique is mainly used for homogeneous, specifically prepared samples, where the signal is averaged over the whole irradiated volume. 2-D resolved data is acquired with imaging techniques by either sample scanning with a focused beam or by using an area detector. Finally, a three dimensional map of oxidation states inside the sample volume can be obtained, combining the XANES technique with tomography. This is a unique method to obtain micrometer-resolved chemical information on bulk samples, opening up a new field for in-volume chemistry. We will present XANES-imaging experiments, dual-energy- tomography scans as well as results of XANES-tomography experiments.