Abstract: An efficient Monte Carlo simulation approach for the estimation of the excess properties of fluid mixtures,the stepwise sampling method,is proposed.This method is carried out by changing the identity of particles in a system one by one during the simulation,so that the whole composition region can be studied.and lots of excess properties can be estimated efficiently and accurately.By means of the proposed method, excess Gibbs free energy,excess enthalpy and excess volume of Argon-Krypton system within the whole composition range have been obtained.The results are compared with those published by McDonald with the conventional approximation method.

Key words: Monte Carlo molecular simulation, Excess property, Fluid mixtures, Ar-Kr