On the phase diagrams of fluids of linearly fused Lennard-Jones sites

Abstract

Computational methods which are used to obtain the liquid–gas phase diagram have been compared for the particular case of fluids of linearly fused Lennard-Jones sites, and for aspect ratios ranging from 1 to 3. Gibbs ensemble Monte Carlo results for the liquid–gas coexistence line are compared with those obtained by fitting the van der Waals isotherms directly obtained by Monte Carlo simulations. The combination of Gibbs ensemble simulation method together with Wegner-type fits, as obtained from scaling arguments, is found to give reliable coexistence data. In particular, the Wegner-type fit is shown to be applicable even quite far from the critical point. The relevance of the isotherm fitting method is discussed mainly in view of results thus obtained, which are quite fair for short aspect ratios but worsen significantly for the larger ones.