Related Experiment Video
Updated: Apr 24, 2026

Analyzing Melts and Fluids from Ab Initio Molecular Dynamics Simulations with the UMD Package
Published on: September 17, 2021
Communication: Low-temperature approximation of the virial series for the Lennard-Jones and modified Lennard-Jones
1National University of Shipbuilding, Geroyev Stalingrada avenue 9, Mykolayiv 54025, Ukraine.
Abstract:
The regularity of the existing data on the virial coefficients for the Lennard-Jones and modified Lennard-Jones models has allowed a rough extrapolation to the coefficients of higher orders. The corresponding approximation of the infinite virial series has been proposed for the limited temperature interval: 0.4-0.8 of the critical temperature. The loci of zero points of isothermal bulk modulus obtained on the basis of this approximation are close to the vapor-liquid branch of the experimental binodal rather than spinodal. In addition, those points ((dP/dV)T = 0) almost coincide with the divergence points of the approximated virial series that may eliminate some disputable questions about the boundaries of adequacy for the virial equation of state and makes the theoretical isotherms qualitatively similar to the real in the condensation region.
Related Concept Videos
The Van der Waals Equation
Thermodynamic Potentials
Heat Capacities of an Ideal Gas III
Heat Capacities of an Ideal Gas II
Real Gases: Effects of Intermolecular Forces and Molecular Volume Deriving Van der Waals Equation
Van der Waals Equation
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the...

