Lennard–Jones Chain Model for Self-Diffusion of n-Alkanes

The Lennard–Jones chain model, which was developed from the equation for the self-diffusion coefficient in a Lennard–Jones fluid and the molecular dynamics simulation data of a tangent hard-sphere chain fluid, is used to calculate the self-diffusion coefficient of n-alkanes. n-Alkanes are characterized by a Lennard–Jones segment diameter, a segment–segment interaction energy, and a chain length expressed as the number of segments. The equation represents the experimental self-diffusion coefficients with an average absolute deviation of 3.93% for 16 n-alkanes covering wide ranges of temperature and pressure. The correlated results are compared with those of the rough Lennard–Jones model. A generalized version of the Lennard–Jones chain model is presented which requires only the carbon number in order to predict n-alkane self-diffusivity.