Demixing and surface-induced population inversion of a binary Gaussian mixture in nanopores

Abstract

We investigate the demixing and the surface-induced population inversion of a binary Gaussian mixture, which exhibits the fluid-fluid demixing transition of the bulk system, in a nanopore. The result shows that the population inversion is the typical shift of the first-order fluid-fluid demixing transition due to the confinement effect. The population inversion line is affected by the crossinteraction between unlike species σ12, the mole fraction of species x2, and the slit width H. At a low cross-interaction between unlike species, the population inversion line for x2 xc. At a high cross-interaction, for x2 xc, it is shifted toward a lower density.