Local g(r) properties in liquids probed by high-temperature EXAFS

Recent experimental advances in high-temperature X-ray absorption spectroscopy (XAS) have stimulated applications to the field of liquid metals and semiconductors. It is now possible to reach the 3000 K temperature range under vacuum or controlled atmosphere. Accurate XAS experiments under high-temperature conditions have been performed on crystalline, molten and highly supercooled metals. Initial applications included liquid and supercooled Sn, Ge, Cu, Ag, and Rh at various temperatures. Reliable short-range pair distribution g(r) functions have been determined using ab initio multiple-scattering calculations. The results are directly comparable with diffraction experiments or molecular dynamic simulations, XAS is found to be particularly sensitive to the first rise of the g(r) and can be considered a reliable complementary technique for studying the short-range structure of liquids. A clear trend in the shape of g(r) as a function of temperature is usually found. The application of this technique to liquid Sn over a large temperature range is reported.