Entropy-driven phases at high coverage adsorption of straight rigid rods on two-dimensional square lattices

CO2–CH4 Exchange Process in Structure I Clathrate Hydrates: Calculations of the Thermodynamic Functions Using a Flexible 2D Lattice-Gas Model and Monte Carlo Simulations

“…Accordingly, general conclusions such as the displacement of CH 4 by CO 2 and the highest entropy (largest number of molecular configurations) associated with CO 2 are expected to be valid also for real 3D systems. A similar behavior has been observed for elongated objects adsorbed on 2D and 3D lattices, showing that isotropic and nematic phases are the basis to understand the thermodynamic properties of the system, and that these phases appear in two and three dimensions. − ,, However, a more detailed analysis of the ways to arrange the guest molecules in the cavities would require the extension of the current model to 3D (Supporting Information).…”

“…A similar behavior has been observed for elongated objects adsorbed on 2D and 3D lattices, showing that isotropic and nematic phases are the basis to understand the thermodynamic properties of the system, and that these phases appear in two and three dimensions. [24][25][26][27][28][29][30]62,63 However, a more detailed analysis of the ways to arrange the guest molecules in the cavities would require the extension of the current model to 3D (Supporting Information).…”

“…The value of k min depends on the lattice geometry, being k min = 7 for square , and triangular lattices and k min = 11 for honeycomb lattices. As it was shown in refs − , the study on the configurational entropy of the adsorbed phase as a function of the coverage allows us to explore the different phases (and orientational transitions) that appear on the surface with increasing the density of adsorbed k -mers. For low coverage, the system presents no order and, accordingly, the entropy corresponds to a state of isotropically distributed k -mers.…”

“…In the case of lattice models (which is the topic of this paper), several papers were devoted to the detailed study of the surface phase transitions occurring in a system of straight hard rods of length k ( k -mers) adsorbed on two-dimensional substrates. − In these articles, it was found that, for k < k min , there is no phase transition, but for k ≥ k min , as density is increased, there are three phases: a low-density disordered (isotropic) phase, an intermediate-density nematic phase, and a high-density phase in which there is no orientational order. The value of k min depends on the lattice geometry, being k min = 7 for square , and triangular lattices and k min = 11 for honeycomb lattices.…”

Cluster approximation applied to multisite-occupancy adsorption: configurational entropy of the adsorbed phase for dimers and trimers on triangular lattices

“…MC simulations developed in ref. 39 showed that Dhar-Rajesh's theoretical results and simulation data coincide, within the statistical uncertainty, in the range k Z 6. The results in ref.…”