The two-dimensional monatomic Leonard-Jones system: triple point and critical point

We introduce a Leonard-Jones (L-J) interaction into the two-dimensional (2D ) Collins model, and consider the existence of the holes that are called th e molecular fraction. The Gibbs free energy of solid, liquid and gas has be en derived. From the Gibbs function we have obtained the whole diagram of t he 2D monatomic L-J system, which includes the melting line, vaporization l ine, sublimation line and the triple point. Also, we have discussed a few p roperties of the critical point.