Liquid-gas phase behavior of an argon-like fluid modelled by the hard-coretwo-Yukawa potential

We study a model for an argon-like fluid parameterized in terms of a hard-c ore repulsion and a two-Yukawa potential. The liquid-gas phase behavior of the model is obtained from the thermodynamically Self-Consistent Ornstein-Z ernike Approximation (SCOZA) of Hoye and Stell, the solution of which lends itself particularly well to a pair potential of this form. The predictions for the critical point and the coexistence curve are compared to new high resolution simulation data and to other liquid-state theories, including th e hierarchical reference theory (HRT) of Parola and Reatto. Both SCOZA and HRT deliver results that are considerably more accurate than standard integ ral-equation approaches. Among the versions of SCOZA considered, the one yi elding the best agreement with simulation successfully predicts the critica l point parameters to within 1%. (C) 2001 American Institute of Physics.