Microscopic mechanisms of diffusion of higher alkanes

With the use of n-triacontane models as examples, abnormal characteristics of diffusion that manifest themselves during the application of the Einstein-Smoluchowski relationship and the asymptotic behavior of velocity autocorrelation function of the molecule-mass centers that is used to calculate the diffusion coefficient via the Green-Kubo formula are investigated. On the basis of the data of complementary approaches, the microscopic mechanisms of diffusion in higher alkanes are outlined. The applicability of the Stokes-Einstein relationship for the viscosity coefficient is demonstrated.