Molecular dynamics simulation of the structure of C6 alkanes

Abstract

The models of hexane, 2,3-dimethylbutane, and cyclohexane are obtained by the method of classical molecular dynamics using the GROMACS software package. Two different force fields (the all-atom description and the approach of united atoms) are used. Radial distribution functions (RDFs) are calculated for the molecular centers of mass, and the shapes of Delaunay simplices are analyzed. It is shown that the most compact molecules (cyclohexane and 2,3-dimethylbutane) are located in the space as atoms in simple liquids. Thus, the structural distinctions between liquid cyclohexane and 2,3-dimethylbutane are the same as between simple liquids of the corresponding density.