Positional ordering of hard adsorbate particles in tubular nanopores

Abstract

The phase behavior and structural properties of a monolayer of hard particles is examined in such a confinement where the adsorbed particles are constrained to the surface of a narrow hard cylindrical pore. The diameter of the pore is chosen such that only first- and second-neighbor interactions occur between the hard particles. The transfer operator method of [Percus and Zhang, Mol. Phys. 69, 347 (1990)MOPHAM0026-897610.1080/00268979000100241] is reformulated to obtain information about the structure of the monolayer. We have found that a true phase transition is not possible in the examined range of pore diameters. The monolayer of hard spheres undergoes a structural change from fluidlike order to a zigzaglike solid one with increasing surface density. The case of hard cylinders is different in the sense that a layering takes place continuously between a low-density one-row and a high-density two-row monolayer. Our results reveal a clear discrepancy with classical density functional theories, which do not distinguish smecticlike ordering in bulk from that in narrow periodic pores.

My model, it has three layers: a reduced model of smectic formation in two dimensions

“…Percus & Zhang [17] were the first to suggest that, as the width of the tunnel was increased, some kind of ordering may take place. While we can rule out a true phase transition with the help of van Hove [18], Gurin et al [19,20] indeed show that a mono-layer smoothly gives way to a smectic-like pair.…”

Highly confined mixtures of parallel hard squares: A density-functional-theory study

“…Obviously, if a DF based on the two-body probability density, instead of the one-body density, could be constructed, it would certainly contain information on the finiteness of the system along y. Therefore, at present, results from the (one-body density-based) DF and the TMM applied to the study of systems with PBC cannot be compared [48]. Fig.…”