Tridimensional imaging of local structure by x-ray absorption spectroscopy

Current x-ray absorption spectroscopy (XAS) data-analysis of ordered and disordered systems is based on a peak decomposition of the n-body distribution functions. The limitation of this approach can be particularly severe for the purpose of modeling the local geometry in liquid and amorphous systems. We have developed a successful method for quantitative analysis of highly disordered structures using the Reverse Monte Carlo (RMC) refinement that can be applied simultaneously to diffraction and XAS data, allowing the construction of realistic tridimensional models. Here we present the results of the application of the method to gaseous Br2 and to liquid Cu. The method incorporates all of the advances related to the application of advanced multiple-scattering (MS) codes and the n-body expansion for XAS data-analysis (GNXAS).