Equation of State and Transport Data on Expanded Liquid Rubidium up to 1700 °C and 400 bar

Experimental results have been obtained for the density ρ, electrical conductivity σ, and the thermoelectric power S of liquid rubidium as a function of temperature (300–1700°C) and pressure (1–400 bar). For that purpose cells of molybdenum and molybdenum‐rhenium‐alloys were developed which allow the simultaneous measurement of ρ, σ, and S. The experiments were performed in an internally heated pressure vessel containing argon as pressure transmitting medium. ‐ A model of hard spheres immersed in a uniform background potential was found to give a fair description of the p‐V‐T data, for densities larger than the metal‐nonmetal‐transition‐density, i. e. for densities between 1.4 and 0.7 g/cm3. A modified Van der Waals equation of state with only two adjustable parameters was developed which fits the experimental data between 1.4 and 0.7 g/cm3. Effective hard‐sphere diameters were determined by using the experimental values of the thermal pressure coefficient magnified image