Computer simulation of trifluoromethane properties with ab initio force field

Area of Science:

• Computational Chemistry
• Molecular Dynamics
• Physical Chemistry

Background:

• Understanding intermolecular interactions is crucial for predicting molecular behavior.
• Trifluoromethane (CH3F) is a significant molecule in various industrial and atmospheric processes.
• Accurate potential energy surfaces are essential for reliable molecular simulations.

Purpose of the Study:

• To calculate accurate intermolecular interaction potentials for the trifluoromethane dimer.
• To develop and validate an ab initio force field for molecular simulations of trifluoromethane.
• To compare simulation results with experimental data to assess force field accuracy.

Main Methods:

• Hartree-Fock (HF) and second-order Møller-Plesset (MP2) perturbation theories were used for potential calculations.
• Coupled cluster with single and double and perturbative triple excitation [CCSD(T)] calculations were employed for calibration.
• Pople and Dunning basis sets, along with extrapolation methods, were utilized to obtain basis set limit potentials.
• A 5-site force field was parameterized using MP2 potential data.
• Molecular dynamics simulations were performed using the developed ab initio force field.

Main Results:

• Intermolecular interaction potentials for the trifluoromethane dimer were computed across 15 orientations.
• An ab initio force field was successfully parameterized from the calculated MP2 potentials.
• Molecular dynamics simulations demonstrated quantitative agreement with experimental radial distribution functions.
• Self-diffusion coefficients obtained from simulations closely matched experimental values under various conditions.

Conclusions:

• The developed ab initio force field accurately describes the intermolecular interactions of trifluoromethane.
• The study validates the use of ab initio calculations and molecular dynamics for predicting molecular properties without prior experimental data.
• The findings provide a reliable computational tool for studying trifluoromethane systems.