ON PERTURBATION EXPANSIONS FOR ASSOCIATED FLUIDS

A feasibility study of applicability of a perturbation expansion for evaluating properties of highly associated fluids is undertaken. It is shown that the long-range electrostatic forces can be considered as a mild perturbation only, provided that the reference potential includes the hydrogen bonding interaction. Perturbed Monte Carlo simulations on two different shortrange reference systems defined for the realistic ST2 water potential show that the structures of the ST2 water and appropriately chosen reference fluids are practically identical and that the expansion of the Helmholtz free energy converges. © 1990 Academia, Publishing House of the Czechoslovak Academy of Sciences.