Vol. 12, no.1, 2020


Thermodynamics and the bottom size limit of its applicability

Yuri K. Tovbin

Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, http://igic.ras.ru/
Moscow 119991, Russian Federation
E-mail: tovbinyk@mail.ru

Received February 14, 2020; revised February 21, 2020; accepted February 24, 2020
Abstract. For the description of the size fluctuations the molecular theory on the basis of the lattice-gas model, which unique gives equal-accuracy results in all range of density, and the finite-difference calculation reflecting a discrete structure of substance, are used. The bottom limit of the thermodynamics applicability is defined by a size for which at calculations of the thermodynamic functions both the discreteness of a substance and the contributions from spontaneous fluctuations can be ignored. Estimations of the sizes of the two-dimensional and spherical isolated drops and for their internal areas of phases are constructed, less which thermodynamic approaches cannot be applied. It is received that an influence of intermolecular interactions and movements of molecules in dense phases on size fluctuations is as much as possible shown at average density. It keeps estimations for size fluctuations which are most important for small and large densities. The received estimations are focused on a wide spectrum of the small systems arising at formation of a new phase and in high–dispersed systems.

Keywords: thermodynamics, molecular theory, lattice gas model, small systems, discreteness of substance, fluctuations, difference calculus

PACS: 64.60.My 64.60.Q- 68.35.Md 82.60.Nh

RENSIT, 2020, 12(1):17-28. DOI: 10.17725/rensit.2020.12.017.

Full-text electronic version of this article - web site http://en.rensit.ru/vypuski/article/312/12(1)17-28e.pdf