CALCULATION OF EXCESS FREE-ENERGY FROM THE AVERAGED EFFECTIVE ACCEPTANCE RATIO IN MONTE-CARLO SIMULATION FOR ARGON, NITROGEN AND WATER

Abstract

A practical method is proposed to evaluate the excess free energy of model potential systems in the Monte Carlo simulation. The excess entropy is calculated from the average of effective acceptance ratio of random configuration in the cell with fixed volume through a separate Monte Carlo procedure. No reference system is needed in this method. This method is applied to the Lennard-Jones and two-center-Lennard-Jones systems. Also, this method is applied to the TIP4P and ST2 models of liquid water. The results of this method give good agreement compared with previous results by other methods. This method saves considerably computing time.