Pressure-induced change of the chemical short-range order in liquid compounds

Hattori, Takanori   ; Tsuji, Kazuhiko*

To reveal the effect of the covalent/ionic chemical bonding character on the pressure-induced structural changes, we have investigated the liquid structures of various tetrahedrally bonded materials under high pressure. The results have shown that these liquids show various high-pressure behaviors, depending on the covalent/ionic character. However, these results are based on the average structure. To observe partial structures is inevitable to understand the nature of the various structural changes in liquid compounds. For this purpose, we have developed the method to determine the partial structure in liquid compounds at high pressures using an anomalous X-ray scattering method and applied it to liquid AgI. The obtained partial structural functions are in good agreement with the results of ab-initio MD calculation, which supports the validity of the AXS method to investigate the chemical short-range order in the liquid compounds.