Molecular Dynamics of Binary Fluids in the Region of the Critical Mixing Point: I. Experimental Fundamentals and the Adjustment of the Lennard-Jones Potential Parameters

In two subsequent articles we shall report our molecular dynamics investigations for the three partially miscible fluid mixtures CH4/CF4; Ne/Kr; He/Xe. The goal of these studies was the simulation of these mixtures at the larger vicinity of the critical mixing point and the investigation of the microscopic behaviour. This first part describes basic aspects of modelling a critical point by molecular dynamics calculations (MDC) and examines the experimental and theoretical data for the larger neighbourhood of a critical mixing point of binary fluids. For the systems under study it is shown that Lennard-Jones type potentials can serve as an appropriate basis for MDC. The adjustment of the Lennard-Jones potential parameters of the 1-2 interaction was done in terms of the parameters occuring in the Redlich-Kwong equation of state. The second article1 is concerned with the actual MD-results on the static and dynamic microscopic structure of the mixtures for the region of the critical mixing point. It is shown that the near-critical range of the systems is simulated reasonably by our MDC.