Pressure-energy correlations and thermodynamic scaling in viscous Lennard-Jones liquids

Abstract

We use molecular dynamics simulation results on viscous binary Lennard-Jones mixtures to examine the correlation between the potential energy and the virial. In accord with a recent proposal [U. R. Pedersen et. al. Phys. Rev. Lett. 100, 015701 (2008)], the fluctuations in the two quantities are found to be strongly correlated, exhibiting a proportionality constant, Gamma, numerically equal to one-third the slope of an inverse power law approximation to the intermolecular potential function. The correlation is stronger at higher densities, where interatomic separations are in the range where the inverse power law approximation is more accurate. These same liquids conform to thermodynamic scaling of their dynamics, with the scaling exponent equal to Gamma. Thus, the properties of strong correlation between energy and pressure and thermodynamic scaling both reflect the ability of an inverse power law representation of the potential to capture interesting features of the dynamics of dense, highly viscous liquids.

5 pages, 4 figures; published version, one figure removed

References in corpus (10)

• Thermodynamic Scaling of the Viscosity of Van Der Waals, H-Bonded, and Ionic Liquids
• Pressure-energy correlations in liquids. I. Results from computer simulations
• Understanding fragility in supercooled Lennard-Jones mixtures. I. Locally preferred structures
• Strong pressure-energy correlations in van der Waals liquids
• Pressure-energy correlations in liquids. II. Analysis and consequences
• Thermodynamic scaling of diffusion in supercooled Lennard-Jones liquids
• Phase diagram of a polydisperse soft-spheres model for liquids and colloids
• Single-order-parameter description of glass-forming liquids: A one-frequency test
• Glass-forming liquids: One or more "order" parameters?
• Understanding fragility in supercooled Lennard-Jones mixtures. II. Potential energy surface

Cited by in corpus (7)

• A repulsive reference potential reproducing the dynamics of a liquid with attractions
• Density scaling in viscous liquids: From relaxation times to four-point susceptibilities
• NVU perspective on simple liquids' quasiuniversality
• Activation Volume in the Density Scaling Regime: Equation of State and Its Test by Using Experimental and Simulation Data
• Correlation of the scaling exponent of the diffusivity-density function in viscous liquids with their elastic properties
• A plausible interpretation of the density scaling of the diffusivity in viscous liquids
• Estimating the density scaling exponent of viscous liquids from specific heat and bulk modulus data