Effect of total and pair configurational entropy in determining dynamics of supercooled liquids over a range of densities

Abstract

In this paper, we present a study of supercooled liquids interacting with the Lennard Jones potential and the corresponding purely repulsive (Weeks-Chandler-Andersen) potential, over a range of densities and temperatures, in order to understand the origin of their different dynamics in spite of their structures being similar. Using the configurational entropy as the thermodynamic marker via the Adam Gibbs relation, we show that the difference in the dynamics of these two systems at low temperatures can be explained from thermodynamics. At higher densities both the thermodynamical and dynamical difference between these model systems decrease, which is quantitatively demonstrated in this paper by calculating different parameters. The study also reveals the origin of the difference in pair entropy despite the similarity in the structure. Although the maximum difference in structure is obtained in the partial radial distribution function of the B type of particles, the rdf of AA pairs and AB pairs gives rise to the differences in the entropy and dynamics. This work supports the observation made in an earlier study [A. Banerjee et al., Phys. Rev. Lett. 113, 225701 (2014)] and shows that they are generic in nature, independent of density.

Validity of the Rosenfeld relationship: A comparative study of the network forming NTW model and other simple liquids

“…It has been used in many recent studies of slow relaxation 21,33 . In this work, we consider only the self-part of the total overlap function (i.e.…”

Communication: Pseudoisomorphs in liquids with intramolecular degrees of freedom

“…Judging from the Science Citation Index this discovery was not appreciated by * tbs@ruc.dk the broad scientific community until about fifteen years ago. Since then excess-entropy scaling has been reported in many different contexts [21,[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]. Rosenfeld justified excess-entropy scaling by assuming the system in question can be approximated by a state-point dependent hard-sphere system, an argument that is difficult to generalize to elongated or flexible molecules.…”

Connecting diffusion and entropy of bulk water at the single particle level

“…In general, the thermodynamic fragility is studied by evaluating the temperature dependence of configurational entropy. The temperature dependence of S Conf is given as, 22 TS Conf.…”

“…Thermodynamic integration has been widely used in determining the total entropy of the system with water and water-like liquids. [19][20][21][22] The vibrational entropy is calculated by making harmonic approximation to the local potential energy minimum. The constant A AG in the AG relation has been associated with the high temperature activation energy, 20 and it has been found to depend strongly on the density of the system.…”

“…The constant A AG in the AG relation has been associated with the high temperature activation energy, 20 and it has been found to depend strongly on the density of the system. 22,23 Most of the studies devoted to the relation between diffusion and entropy focused on the thermodynamic and dynamic properties of the whole system. However, an understanding of the behaviour of individual water molecules in terms of thermodynamics and dynamics is missing.…”