A 2-DIMENSIONAL LENNARD-JONES LATTICE-GAS .3. MONTE-CARLO STUDY OF ORDERING ON RECTANGULAR LATTICES

The Monte Carlo simulation method was used to investigate ordering of particles interacting with the (12,6) Lennard-Jones potential and adso rbed on rectangular lattices. Systems consisting of particles of diffe rent sizes adsorbed on lattices characterized by different sizes of un it lattice cell were investigated. It is demonstrated that the ordered state of the adsorbed layer depends strongly on the relative sizes of adsorbed atoms and of the unit lattice cell of the solid surface latt ice. Phase diagrams for several systems are determined and the critica l behaviour of adsorbed layers is discussed. In particular, it is show n that despite the differences in the structure of the ordered state, all the systems considered here exhibit critical behaviour correspondi ng to the universality class of the two-dimensional Ising model.