Departures from Joule's Law in Dense Liquids near Freezing Related to Vacancy Properties in Hot Crystals

Abstract

Abstract The departures from Joule's Law that the internal energy U is independent of volume V are first expressed in dense liquids in terms of specific heats and the isothermal compressibility. For condensed rare gases, described by density independent pair potentials, (∂U/∂V)T is shown to be closely related to the vacancy formation energy Ev , a correction term dependent on the density dependence of the pair function being displayed explicitly. For metals with density-dependent pair potentials, (∂U/∂V)T is shown to involve the vacancy formation volume.