Determination of two- and three-body correlation functions in ionic solutions by means of MD and EXAFS investigations

The solvation structure of Sr2+ ions in acetonitrile has been studied by x-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations. The extended x-ray absorption fine structure (EXAFS) above the Sr K-edge has been interpreted in the framework of the multiple scattering (MS) formalism and, for the first time, clear evidence of MS contributions has been found for non-complexing ions in solution. Molecular dynamics has been used to generate the partial pair g(r) and the three-body g(r(1), r(2), theta) distribution functions from which a model chi(k) has been constructed. An excellent agreement has been found between the theoretical and experimental data. This result demonstrates the ability of the XAS technique in probing three-body correlation functions in solutions.