SUPERSELECTIVITY AND SOLVATION FORCES OF A 2-COMPONENT FLUID ADSORBEDIN SLIT MICROPORES

We use the grand canonical Monte Carlo simulation technique to calcula te adsorption of mixtures in molecularly narrow slit pores immersed in a two-component bath of spherical molecules that are different in siz e. The composition of the pore fluid oscillates strongly with the pore width. The oscillations reflect the differing ability of each molecul e to pack as layers in the pore. Even in pores wide enough to admit bo th components, this difference in packing ability leads to a shut-out of the smaller component. Trends in the calculated solvation force agr ee with both experiment and theory.