Theory of the Thermodynamic Properties of Liquid Metals

Abstract

Thermodynamic properties of the liquid metals Li, Na, K, and Al are calculated using a pseudopotential model together with an application of thermodynamic perturbation theory based on the Gibbs-Bogoliubov inequality. The theory is used to predict many properties associated with the melting phenomenon; for example, the melting temperature and density as a function of temperature, and the latent heat of fusion. It is found that the theory reproduces the trend in latent heats between the alkali metals, in contrast to previous work, although quantitative agreement with experiment is no better than has been obtained before. The theory is also applied to the prediction of thermodynamic properties on and away from the melting curve; in particular, the specific heat and velocity of sound of sodium are calculated over a wide range of temperature. Agreement with experiment is found to be good.