Improved GAFF2 parameters for fluorinated alkanes and mixed hydro- and fluorocarbons

Area of Science:

• Computational chemistry
• Materials science
• Molecular modeling

Background:

• Accurate molecular mechanics models are crucial for simulating chemical and physical properties.
• Existing force fields may not precisely capture the behavior of perfluorocarbons and mixed hydro- and fluorocarbons.
• Self-assembled monolayers (SAMs) are important for surface science and nanotechnology.

Purpose of the Study:

• To develop and validate improved molecular mechanics models for perfluorocarbons and mixed hydro- and fluorocarbons.
• To enhance the accuracy of the GAFF2 force field for these specific chemical classes.
• To assess the impact of these improved models on predicting structural and mechanical properties.

Main Methods:

• Development of new GAFF2-based force field parameters.
• Benchmarking against single molecule geometries.
• Simulation of condensed phases, specifically perfluoro-octadecane phosphonic acid self-assembled monolayers.
• Analysis of torsion angles and mechanical properties via simulated indentation.

Main Results:

• Demonstrated considerable improvement in the accuracy of torsion angles for perfluorocarbons and mixed hydro- and fluorocarbons.
• Validated the enhanced models through benchmarking in both gas and condensed phases.
• Illustrated the impact of the improved models on the mechanical properties of self-assembled monolayers.

Conclusions:

• The refined GAFF2-type molecular mechanics models offer superior accuracy for perfluorocarbons and related compounds.
• These improved models are essential for reliable simulations of structural and mechanical behaviors.
• The study provides a valuable tool for computational studies in materials science and chemistry.