An Investigation On Effective Center Symmetric Model Potentials By Statistical Thermodynamics And Computer Simulation

Theory of liquid state and Monte Carlo simulation techniques in the field of simple liquid are review at first. On these bases, the present author investigates the structural properties of a model fluid dictated by an effective inter-particle oscillatory potential by grand canonical ensemble Monte Carlo(GCEMC) simulation and classical density functional theory. The structural properties we studied include a radial distribution function in bulk and density distribution due to influence of several external fields. Two recently proposed theoretical approaches in the field of atomic fluids are amployed for the calculations. One, an Ornstein-Zernike integral equation theory approach, the other, a third order+second order perturbation density functional theory. Then, a comparison of the GCEMC results and theoretical calculations is given to test the validity of the two theoretical approaches for the effective oscillatory potential, and it is found that the two theoretical approaches are readily applicable to the effective oscillatory potential.Then, a constant NVT-Monte Carlo technique is employed to simulate for the honeycomb potential in three dimensions. A Benedict-Webb-Rubin(MBWR) equation of state (EOS), proposed by Nicolas et al., and containing 32 linear coefficients, is applied in this paper to fit the simulation results of the reduced pressure and reduced exess internal energy into an analytic EOS. The present NVT Monte Carlo simulation is performed over a range of a reduced density ranging from 0.1 to 0.95, and a reduced temperature 5.0 to 0.08 respectively, and the resulting reduced pressure p* and reduced exess internal energy uex* (the unusual data being picked out) are fitted into the analytical MBWR EOS by establishing the relevant 32 linear coefficients. It is shown that within the scope of application of the EOS, the simulation data of p* and uex*, which are not used in the fitting procedure, can be in very good agreement with those due to the EOS.