EXAFS study of U(6) compounds: a new approach to data analysis

The regularisation method is applied to determine three partial pair correlation functions (PCFs) from one EXAFS spectrum. The mathematical procedure is discussed and applied to the EXAFS analysis of UO2(HAsO4) x 4H2O. The measurements were performed at the Rossendorf Beamline (ROBL) at the ESRF in Grenoble. The As K edge and the U L3-edge absorption spectra were recorded in transmission mode at temperatures of 41 K and 15 K, respectively. From the U L3-edge EXAFS spectrum, we obtain the PCFs of the pairs U-U, U-As and U-O and determine the structural parameters for the first and the second co-ordination shells of each pair. The PCFs of the pairs As-U, As-As and As-O are obtained from the As K-edge EXAFS spectrum. (authors)