Histogram reweighting and finite-size scaling study of the Lennard-Jones fluids

Phase diagrams and critical constants for the long-range corrected, the tru ncated, and the truncated and shifted Lennard-Jones fluids with various val ues of the potential cutoff were computed from molecular simulations. Criti cal parameters were obtained from mixed-field finite-size scaling analysis. Multiple histogram reweighting was used to compute the phase envelop at te mperatures well below criticality. For the long-range corrected fluid, the coexistence curve is systematically shifted to higher chemical potentials f or a cutoff of 5.0 sigma compared with that for a cutoff of 2.5 sigma. The difference in the critical temperature for the truncated and truncated and shifted potentials decreases from 10 to 3.6% as the cutoff increases from 2 .5 sigma to 3.5 sigma. The critical temperature for the long-range correcte d fluid is about 1.4% larger than that for the truncated fluid with a cutof f of 5.0 sigma. The average absolute deviations of the coexistence densitie s between the truncated and long-range corrected fluid with r(c) = 5.0 sigm a are about 0.8 and 1% for the vapor and liquid branches, respectively. Thi s indicates that the truncated Lennard-Jones fluid with a cutoff of 5.0 sig ma is a reasonable quantitative approximation to the full Lennard-Jones flu id. (C) 2001 Elsevier Science B.V. All rights reserved.