Vapor-liquid equilibria of the two-dimensional Lennard-Jones fluid(s)

Two-dimensional systems are interesting both from a purely theoretical and from an experimental point of view. Examples of real systems that behave effectively as two-dimensional systems are monolayers adsorbed on solid substrates’ and surfactants adsorbed on an air/water interface.’ If a fluid is confined between two parallel plates, the phase behavior of such a system has two limiting cases. For infinite plate separation the system is identical to the threedimensional bulk system but when the separation between the plates is of the order of a molecular diameter, the fluid behaves like a two-dimensional bulk fluid. In order to study the influence of confinement on the phase behavior it is important to know the phase diagram of the two-dimensional bulk fluid. The Lennard-Jones potential is given by