Development of an all-atoms force field from ab initio calculations for alternative refrigerants

A general all-atoms force field (FF) for atomistic simulation of low molecular weight hydrofluorocarbons (HFCs) was developed using state-of-art ab initio calculations and empirical parameterization techniques. The FF is based on ab initio quantum mechanical calculations for the valence parameters and on molecular dynamics (MD) simulations for the tuning of the Lennard-Jones (LJ) parameters describing the dispersion forces. tion of the proposed FF has been made versus intramolecular properties of isolated molecules, vibrational spectra, and intermolecular properties of liquid state molecules such as cohesive energy, enthalpy of vaporization and density for molecules of interest. The reported results show that the present force filed enables accurate and simultaneous prediction of structural, conformational, vibrational and thermophysical properties for low molecular weight HFCs in isolation and in condensed phase. Detailed results of the parameterization and validation are reported.