Physically motivated, robust, ab initio force fields for CO2 and N2.

Area of Science:

• Computational Chemistry
• Materials Science
• Chemical Physics

Background:

• Developing accurate molecular models is crucial for simulating chemical systems.
• Existing force fields often lack physical grounding and transferability.
• Polarizable force fields are essential for systems with significant charge redistribution.

Purpose of the Study:

• To present a novel methodology for creating physically motivated, first-principles polarizable force fields.
• To apply this methodology to carbon dioxide (CO2) and nitrogen (N2).
• To validate the developed force fields against experimental data.

Main Methods:

• Utilized symmetry-adapted perturbation theory (SAPT) for fitting interaction parameters.
• Decomposed interactions into exchange, electrostatic, induction, and dispersion components.
• Employed physically appropriate functional forms for each interaction term.

Main Results:

• Developed and validated polarizable force fields for CO2 and N2.
• Achieved excellent agreement with experimental data, including second virial coefficients, density, and phase behavior.
• Demonstrated robustness and transferability to gas mixtures.

Conclusions:

• The novel methodology yields accurate and transferable polarizable force fields.
• These force fields are suitable for modeling CO2 and N2 in diverse environments.
• Anticipated applications include adsorption studies in polar and heterogeneous media.