chapter  58
3 Pages

Small systems by J.W. Gibbs

The first type of additions is the use by J.W. Gibbs of the same sequence of establishment of equilibria (first mechanical equilibrium, then chemical equilibrium) when considering the thermodynamics of a curved boundary, as in the Kelvin equation. In particular, this sequence is emphasized in the analysis of the stability of curved boundaries (pp. 220-230 in [8]) and in the treatment of other problems in the thermodynamics of small bodies. (The original texts of Gibbs are not repeated: they refer to the relevant pages.) This led to the fact that the thermodynamic criterion of stability dP/dV < 0, referring to macroscopic systems, significantly overstates the range of real parameters corresponding to complete equilibrium for small bodies under the condition of the equality of all three quantities in different phases independent of each other: P, T and μ (corresponding, respectively, to mechanical, thermal and chemical equilibria). During the following time this served as a justification for introducing the concepts of metastable states, and the possibility of their interpretation using thermodynamic equations.