Excess chemical potential and surface free energy of a hard-sphere fluid at curved walls: deviations from Morphometric Thermodynamics.

31^st October 2023, 14:00
Ruslan Davidchack
University of Leicester, UK

Abstract

Excess chemical potential (or solvation-free energy) is an important thermodynamic quantity that characterises the properties of fluids in contact with surfaces and the behaviour of fluid mixtures. General theoretical analysis of this quantity is rather complicated and available only for simple systems (like hard-sphere fluids) in various approximations (Perkus-Yevick integral equations, Scaled Particle Theory, density-functional theory). A significant simplification can be obtained under the assumptions of the so-called Morphometric Thermodynamics (MT), based on Hadwiger's theorem from integral geometry. We use a combination of Gibbs-Cahn integration and Widom's particle insertion methods to obtain high-precision measurements of the excess chemical potential and surface-free energy. With these results, we are able to observe deviations from the MT expressions and thus test the extent of applicability of the MT assumptions.