A New Set of Combining Rules for Mie (λ, 6) Potential

Area of Science:

• Computational chemistry
• Physical chemistry
• Materials science

Background:

• Mie (λ, 6) potentials are crucial for simulating fluid properties.
• Current combining rules for unlike interactions in Mie potentials are limited.
• This limits the application of Mie (λ, 6) force fields in complex mixtures.

Purpose of the Study:

• Develop and validate new combining rules for the Mie (λ, 6) potential.
• Improve the prediction of thermophysical properties for fluid mixtures.
• Enhance the applicability of Mie (λ, 6) force fields.

Main Methods:

• Proposed new combining rules using a distortion model and geometric mean approximation.
• Evaluated rules for noble gas pairs using Lennard-Jones potential (a Mie case).
• Assessed Henry's law constants, phase diagrams, and excess molar volumes using molecular simulations (NVT-GEMC, NPT-GEMC, NPT-MC).

Main Results:

• New rules showed better agreement with experimental data for noble gas pairs than traditional rules.
• For asymmetric mixtures, new rules significantly improved accuracy for thermodynamic properties.
• Common rules performed poorly for asymmetric systems, showing larger deviations.

Conclusions:

• The proposed combining rules offer improved robustness and accuracy for Mie (λ, 6) force fields.
• These rules enable broader application to complex fluid mixtures.
• This work addresses a key limitation in simulating mixture properties.