Equation of state for compressed liquid alkali metals

This work extends previous work on the application of the Ihm, Song, and Mason equation of state for compressed liquid alkali metals. The equation of state is based on statistical-mechanical perturbation theory with the perturbation scheme of Weeks, Chandler, and Andersen. As in the previous work, the surface tension and the liquid density at the normal boiling point are the only input parameters. The second virial coefficients of alkali vapours, which are experimentally scarce, have been calculated from the previous corresponding-states correlation for normal fluids. A calculation of the other two temperature-dependent parameters has been performed by scaling. The equation of state has been applied to calculate the liquid density of lithium through to caesium from the melting point up to several hundred kelvins above the normal boiling point at pressures ranging from 100 to 1000 bar. The agreement with experiment is within ±5%.