The origin of the density scaling exponent for polyatomic molecules and the estimation of its value from the liquid structure

Abstract

In this article, we unravel the problem of interpreting the density scaling exponent for the polyatomic molecules representing the real van der Waals liquids. Our studies show that the density scaling exponent is a weighted average of the exponents of the repulsive terms of all interatomic interactions occurring between molecules, wherein the potential energy of a given interaction represents its weight. It implies that potential energy is a key quantity required to calculate the density scaling exponent value for real molecules. Finally, we use the well-known method for potential energy estimation and show that the density scaling exponent could be successfully predicted from the liquid structure for fair representatives of the real systems.

References in corpus (7)

• Thermodynamic Scaling of the Viscosity of Van Der Waals, H-Bonded, and Ionic Liquids
• Pressure-energy correlations in liquids. I. Results from computer simulations
• Pressure-energy correlations in liquids. II. Analysis and consequences
• Strong pressure-energy correlations in van der Waals liquids
• An equation for the description of volume and temperature dependences of the dynamics of supercooled liquids and polymer melts
• Determination of the Thermodynamic Scaling Exponent from Static, Ambient-Pressure Quantities
• "Pseudoisomorphs" in liquids with intramolecular degrees of freedom