K- and L-edge XAFS determination of the local structure of aqueous Nd(III)and Eu(III)

The short-range coordination of Nd( III) and Eu( III) ions in aqueous solut ions has been investigated by means of K-edge x-ray absorption spectroscopy . Experimental data are presented which demonstrate that an accurate determ ination of the Nd( III) and Eu( III) hydration structural parameters can be obtained from the analysis of the K-edge spectra. It is shown that the lar ge widths of the core hole states do not appreciably reduce the potential s tructural information of the K-edge EXAFS data. In addition the available k -range of the K-edge spectra is much wider compared to that of the L-3-edge which is affected by the presence of double-electron excitations in a more severe fashion.