Accurate Force Field for Carbon Dioxide-Silica Interactions Based on Density Functional Theory

Area of Science:

• Materials Science
• Computational Chemistry
• Geochemistry

Background:

• Fluid-silica interfaces are critical in natural and industrial processes.
• Accurate molecular simulations require reliable force fields, particularly for nonbonded interactions.
• Traditional mixing rules for dispersion interactions in simulations lack critical examination.

Purpose of the Study:

• To develop and validate optimized Lennard-Jones parameters for carbon dioxide-silica interactions.
• To improve the accuracy of molecular simulations at fluid-silica interfaces.
• To assess the impact of these parameters on condensed CO2 behavior in silica pores.

Main Methods:

• Utilized density functional theory (DFT) to calculate CO2-silica binding energies.
• Developed new Lennard-Jones parameters optimized against DFT data.
• Applied the silica-DDEC force field with updated parameters for simulations.
• Evaluated parameter performance with other established silica force fields (Clayff, Gulmen-Thompson).

Main Results:

• Standard mixing rules underestimate CO2 binding to silica compared to DFT.
• Optimized Lennard-Jones parameters accurately reproduce DFT-based binding energies.
• Improved parameters enhance the predictive accuracy of multiple silica force fields.
• Simulations reveal effects of optimized parameters on structural and dynamical properties of condensed CO2.

Conclusions:

• Optimized Lennard-Jones parameters are essential for accurate CO2-silica interface simulations.
• The developed parameters improve upon standard methods and enhance existing force fields.
• Accurate modeling of CO2-silica interactions is vital for applications in separations and catalysis.