Computer modeling of liquid propane using three-site potential models

Abstract

Molecular dynamics simulations and ab initio calculations, at the Hartree–Fock level and Mo/ller–Plesset perturbation to the second order energy, have been performed to investigate the modeling of propane using nonlinear three-site pair potentials. Simulation results for the structure and thermodynamic properties of saturated liquid propane compare well with the experimental data when potential models are used in which the interaction sites are located at or close to the geometric centers of CH3 and CH2 groups. One of the empirical potentials has also been compared with the ab initio results for different molecular orientations. The three-site model favors stacked orientations whereas the ab initio propane dimer favors T orientation. This difference is due to the planar geometry of the model molecules. The effect of attractive forces on the structure and thermodynamic properties in the simulated liquid has also been studied and found to be small.