Loci of maxima and minima of thermodynamic functions of a simple fluid

Abstract

Some elementary properties of loci of extrema of thermodynamic functions are established and discussed in connection with maxima and minima of the constant volume specific heat, CV, the isothermal compressibility, χT, and the constant pressure specific heat, CP, along isotherms, and the extremum properties of the isobaric coefficient of expansion, αP, along isobars. Experimental results for fluid argon are used to construct the required loci of extrema. Van der Waals' equation is applied to obtain loci of extrema for χT, CP, and αP, for the speed of sound W, and for related inflexion loci.