Thermodynamic perturbation theory, which was developed, by Chandler, Weeks, Andersen, Verlet and Weis is used to estimate the effective Lennard–Jones (6–12) pair potential parameters of liquid organic compounds at different temperatures. It is found that the estimated Lennard–Jones parameters, sand 1/k, are dependent on temperature and consequently the Lennard– Jones (6–12) pair potential function, uðrÞ; is changed to effective u(r;T).
