Molecular dynamics of small alkanes in an external force field

Abstract

Adiabatic molecular dynamics simulations of ethane and propane-like molecules have been studied under the influence of external compressional and shearing forces. The geometric periodic boundary conditions for the simulations with an external shearing force correspond to flow between parallel interdigitated plates being sheared in opposite directions. The lower energy conformer of the propane-like molecule is bent while the linear conformer has a barrier and energy difference which is the same as that between the trans and gauche conformers of n-butane. Although the strong external fields are found to align the molecules in the direction of the shearing field, no change in the conformational state of the propane-like molecules is observed at the temperatures studied.