Molecular Mobility in Cyclic Hydrocarbons: A Simulation Study

Mixtures of cyclohexane and cyclohexene are investigated by means of all-atom molecular dynamics simulations. Thermodynamic properties (density, enthalpy of vaporization), transport coefficients (different diffusion coefficients, reorientation times), and structural properties (radial distribution functions) were calculated for seven different compositions and compared to experimental results where available. Transport coefficients indicate a nonideal behavior at low cyclohexene concentrations. The problem of determining the mean-squared displacement from a constant pressure simulation is addressed, and a method is derived, which minimizes the artifacts introduced by the rescaling of the periodic box.