Correlations among residual multiparticle entropy, local atomic-level pressure, free volume and the phase-ordering rule in several liquids

A modified Wang-Landau density-of-states sampling approach has been performed to calculate the excess entropy of liquid metals, Lennard-Jones (LJ) system and liquid Si under NVT conditions; and it is then the residual multiparticle entropy (S-RMPE) is obtained by subtraction of the pair correlation entropy. The temperature dependence of S-RMPE has been investigated along with the temperature dependence of the local atomic-level pressure and the pair correlation functions. Our results suggest that the temperature dependence of the pair correlation entropy is well described by T (1) scaling while T (0.4) scaling well describes the relationship between the excess entropy and temperature. For liquid metals and LJ system, the -S-RMPE versus temperature curves show positive correlations and the -S-RMPE of liquid Si is shown to have a negative correlation with temperature, the phase-ordering criterion (based on the S-RMPE) for predicting freezing transition works in liquid metals and LJ but fails in liquid Si. The local atomic-level pressure scaled with the virial pressure (sigma(al)/sigma(av)) exhibits the much similar temperature dependence as -S-RMPE for all studied systems, even though simple liquid metals and liquid Si exhibit opposite temperature dependence in both sigma(al)/sigma(av) and -S-RMPE. The further analysis shows that the competing properties of the two effects due to localization and free volume on the S-RMPE exist in simple liquid metals and LJ system but disappear in liquid Si, which may be the critical reason of the failure of the phase-ordering criterion in liquid Si. (C) 2011 American Institute of Physics. [doi:10.1063/1.3524206]