Molecular dynamics simulations of fluid cyclopropane with MP2/CBS-fitted intermolecular interaction potentials

Area of Science:

• Computational chemistry
• Chemical physics
• Materials science

Background:

• Accurate molecular dynamics simulations of fluid cycloalkanes are hindered by the lack of reliable quantum chemistry-based force fields.
• Cyclopropane, a simple cycloalkane, presents unique modeling challenges due to its ring structure.

Purpose of the Study:

• To construct a novel ab initio force field for fluid cyclopropane.
• To validate the accuracy of the developed force field against experimental data and empirical models.

Main Methods:

• Utilized second-order Møller-Plesset perturbation theory and coupled cluster methods for quantum chemistry calculations.
• Employed Dunning's correlation consistent basis sets to extrapolate interaction energies to the complete basis set limit.
• Regressed force field parameters for a 9-site Lennard-Jones model using calculated interaction energies without empirical data.

Main Results:

• Developed an ab initio force field for cyclopropane, eliminating the need for empirical data.
• Molecular dynamics simulations using the ab initio force field accurately reproduced atom-wise radial distribution functions.
• Calculated self-diffusion coefficients and shear viscosities showed good agreement with experimental data across various thermodynamic conditions.

Conclusions:

• The developed ab initio force field is the first of its kind capable of achieving accuracy comparable to empirical force fields for fluid cyclopropane simulations.
• This work provides a reliable computational tool for studying the behavior of cyclopropane and potentially other cycloalkanes.