Radial distribution function in ionic compounds at high temperature and pressure

RbI and RbBr local atomic structure has been accurately investigated by using Xray absorption spectroscopy (XAS) in a wide range of temperatures, covering the solid and the liquid phase. In the RbI case, the study has been extended also at high pressure up to 3.5 GPa. Rb, Br and I K-edge XAS spectra has been collected and analyzed using the GNXAS package. Multiple scattering and atomic background contributions have been taken into account, providing a very accurate determination of the first shell structural parameters. The experimental partial g(+-)(r) of the RbBr1-xIx ionic alloy are also reported for the solid and the liquid phases, showing the characteristic bimodal distribution in pseudobinary alloys. These results can be very useful for testing the validity of theoretical ionic potentials employed in computer simulations