An X-ray absorption study of gold coordination compounds: EXAFS refinements and double electron excitation background

X-ray absorption spectra at the Au L edges of Au(PPh 3 )Cl, Au(PPh 3 ) 2 Cl and KAuCl 4 .2H 2 O have been collected as a function of temperature. Data analysis of the extended X-ray absorption fine structure was carried out with the GNXAS package performing an appropriate treatment of the multiple-scattering effects involving several ligand atoms. The accuracy of the current analysis procedures for the Au L edges is assessed and the sensitivity to coordination numbers and distances is established. Evidence for the presence of a (2p4f) double-electron excitation in the atomic Au background is obtained for the first time. The results presented in this paper are of general importance for improving data analysis at the Au L edges and in particular for improving the EXAFS results in Au cluster compounds.