Structure independent properties of expanded crystalline mercury

Static and Dynamic Structures of Expanded Fluid Mercury

X-ray diffraction, small angle X-ray scattering and preliminary inelastic X-ray scattering measurements for a metallic fluid up to the supercritical region have been carried out using synchrotron radiation at SPring-8. We obtained the structure factor, S(k), and the pair distribution functions, g(r), for expanded fluid Hg from the liquid to the dense vapour region by X-ray diffraction measurements. Change of the local structure in the metal–insulator transition in fluid Hg is discussed. To obtain information on the density fluctuation in fluid Hg near the critical point, small angle X-ray scattering measurements were carried out at SPring-8. In addition to the static structures, the dynamic structure factor of expanded fluid Hg was obtained for the first time using inelastic X-ray scattering technique newly established at a synchrotron radiation facility of the third generation source. Preliminary results of the first experiment are presented.

Metal-Nonmetal Transitions in Expanded Fluids

The main purpose of the present paper is to study the relationship between the electronic and thermodynamic properties of expanded metallic fluids in the vicinity of the liquid-gas critical point. In particular, it is shown that a theoretical analysis naturally predicts the possible existence of two different kinds of thermodynamic phase transitions—first the atomic gas-to-liquid condensation for which electrons play no explicit role, and secondly the electron-induced first-order phase transition accompanying a metal-nonmetal transition. The thermodynamic behaviours of fluids in the supercritical region are discussed in connection with these two transitions.