Interatomic Lennard-Jones potentials of linear and branched alkanes calibrated by Gibbs ensemble simulations for vapor-liquid equilibria

The interatomic Lennard-Jones (LJ) potential parameters for linear and branched alkanes were analyzed. The values of LJ potential parameters were optimized using gibbs ensemble monte carlo (GEMC) simulations and experimental data for key compounds. The effect of finite system size on the coexistence behavior near the critical point was also investigated. Simulations on larger systems gave a decreased vapor density and increased liquid density at high temperatures resulting in the estimated critical temperature that is a little higher and slightly closer to experimental values.