Corresponding states law for a generalized Lennard-Jones potential.

Area of Science:

• Thermodynamics and Statistical Mechanics
• Computational Physics and Chemistry
• Materials Science

Background:

• Previous work established a universal master curve for vapor-liquid coexistence densities using Mie and Yukawa potentials.
• This curve relates densities to the difference in reduced second virial coefficients (B2) relative to the critical point.
• Generalizations of the Lennard-Jones potential are crucial for modeling diverse intermolecular interactions.

Purpose of the Study:

• To test the universality of the proposed master curve for a generalized Lennard-Jones (LJ) potential.
• To investigate the applicability of this concept to other thermodynamic properties like surface tension and vapor pressure.
• To explore how varying the LJ potential's softness parameter affects phase behavior.

Main Methods:

• Molecular dynamics (MD) simulations were employed to study vapor-liquid coexistence.
• The generalized Lennard-Jones potential was systematically varied by adjusting its softness parameter.
• Simulations covered a temperature range below the critical point, analyzing densities, surface tension, and vapor pressure.

Main Results:

• All investigated properties (densities, surface tension, vapor pressure) exhibited collapse onto master curves.
• The vapor-liquid coexistence curve shape was consistent with that obtained from Mie and attractive Yukawa potentials.
• Surface tension and the logarithm of vapor pressure showed a linear dependence on the reduced second virial coefficient difference.

Conclusions:

• The proposed master curve approach is valid for generalized Lennard-Jones potentials, extending its universality.
• This finding offers a simplified, unified framework for describing vapor-liquid equilibrium across different interaction potentials.
• The observed linear relationships provide predictive power for thermodynamic properties based on virial coefficients.