Statistical thermodynamics of straight rigid rods with nonadditive lateral interactions: Theory and Monte Carlo simulations

The adsorption of a mixture of particles with non-additive interactions: a Monte Carlo study

The adsorption of binary mixtures with non-additive lateral interactions has been studied through grand canonical Monte Carlo simulations in the framework of the lattice-gas model. The traditional assumption of additive lateral interactions is replaced with a more general one including non-pairwise interactions. It is assumed that the energy linking a certain atom with any of its nearest neighbors strongly depends on the state of occupancy in the first coordination sphere of such an adatom. The process has been monitored through the adsorption isotherms and the differential heats of adsorption. Different combinations of both inter- and intra-species interactions have been considered in the analysis. Interesting behaviors were observed and discussed in terms of the low temperature phases formed in the system.

Thermodynamics of the one-dimensional parallel Kawasaki model: exact solution and mean-field approximations

The adsorption isotherm for the recently proposed parallel Kawasaki (PK) lattice-gas model [Phys. Rev. E 88, 062144 (2013)] is calculated exactly in one dimension. To do so, a third-order difference equation for the grand-canonical partition function is derived and solved analytically. In the present version of the PK model, the attraction and repulsion effects between two neighboring particles and between a particle and a neighboring empty site are ruled, respectively, by the dimensionless parameters ϕ and θ. We discuss the inflections induced in the isotherms by situations of high repulsion, the role played by finite lattice sizes in the emergence of substeps, and the adequacy of the two most widely used mean-field approximations in lattice gases, namely, the Bragg-Williams and the Bethe-Peierls approximations.