Gaussian-Charge Polarizable and Nonpolarizable Models for CO2

Area of Science:

• Computational chemistry
• Molecular modeling
• Thermodynamics

Background:

• Developing accurate intermolecular potential models is crucial for simulating molecular systems.
• Carbon dioxide (CO2) properties are essential for various industrial and environmental applications.
• Polarization effects can significantly influence the behavior of molecular fluids.

Purpose of the Study:

• To develop and validate a polarizable intermolecular potential model for CO2.
• To compare the performance of the polarizable model against a nonpolarizable counterpart.
• To assess the impact of polarization on the thermodynamic and transport properties of CO2.

Main Methods:

• Development of a rigid CO2 model with three classical Drude oscillators.
• Parameter optimization using vapor-liquid equilibria (VLE) data.
• Simulation using Gibbs ensemble Monte Carlo and molecular dynamics.

Main Results:

• Both polarizable and nonpolarizable models demonstrated excellent agreement with experimental data for various properties.
• Key properties evaluated include enthalpy of vaporization, second virial coefficient, density, heat capacities, radial distribution functions, diffusion coefficient, and shear viscosity.
• Pure CO2 fluid properties were found to be largely unaffected by polarization.

Conclusions:

• The developed polarizable CO2 model accurately reproduces experimental thermodynamic and transport properties.
• Polarization is not a dominant factor for pure CO2 fluid properties.
• The polarizable model is computationally more expensive but valuable for simulating CO2 mixtures with polar components.