Extended law of corresponding states: square-well oblates

Area of Science:

• Statistical Mechanics
• Physical Chemistry
• Soft Matter Physics

Background:

• The principle of corresponding states describes vapor-liquid coexistence using reduced temperature and density.
• Noro and Frenkel extended this principle to pair potentials with variable ranges.

Purpose of the Study:

• To provide a theoretical basis for extending the law of corresponding states to anisotropic, short-range pair potentials.
• To investigate the applicability of this extended law to systems with anisotropic repulsive and attractive parts.

Main Methods:

• Theoretical analysis to support the extension of the law of corresponding states.
• Grand Canonical Monte Carlo (GCMC) simulations to study vapor-liquid coexistence.
• Second virial perturbation theory to analyze the behavior of the system.

Main Results:

• Binodals for oblate hard ellipsoids with varying square-well interactions collapse into a single master curve in the ΔB2*-ρ plane.
• This collapse is observed for uniform, equator, and pole attractions, confirming the extended law's applicability.
• Simulation results indicate the extended law of corresponding states is independent of local fluid structure.

Conclusions:

• The extended law of corresponding states is valid for anisotropic, short-range pair potentials.
• This principle provides a unifying framework for understanding vapor-liquid coexistence across different interaction potentials.
• The findings are robust and confirmed by both theoretical calculations and simulation data.