Monte Carlo simulations of phase transitions and adsorption isotherm discontinuities on surface compression

Adsorption isotherm predicted from a lattice gas with general lateral interactions in a single-phase regime

“…Adsorption compression occurs when an adsorbing surface attracts the adsorbed particles so strongly into a surface phase that their nearest-neighbour distances are shorter than in the standard bulk fluid (as given by a minimum of the Lennard-Jones potential), thus generating repulsive interactions between the adsorbed particles [47]. To study this phenomenon, one should consider a 3D system of adparticles that are 'soft' (of the Lennard-Jones type) [27,28,47,48] rather than 'hard', as is common in latticegas theories [29,31]. Thus, lattice gases need not be suitable to simulate adsorption compression in an accurate way.…”

“…Then the ground-state intervals are µ − ε < 0 for the fully vacant ground state, 0 < µ − ε < 3ε b for the ground state with the coverage 1/3, 3ε b < µ − ε < 6(ε t + ε b ) for the ground state with the coverage 2/3, and µ − ε > 6(ε t + ε b ) for the fully occupied ground state. The isotherm (28) for this case (with ε b chosen, say, to be twice ε t ) is plotted in figure 2. Near the interval endpoints, i.e.…”

“…Up until now, lattice gases have been successfully applied to investigate various aspects of adsorption, for example, the effect of lateral interactions and surface topography on the adsorbent [15,16,[19][20][21], multi-component adsorption [22,23], confinement and capillary condensation in porous materials [24], hysteresis [25,26], and adsorption compression [27,28]. In particular, much effort has been devoted to the study of adsorption isotherms [6,13,[29][30][31][32][33] with the help of approximative techniques.…”