Molecular dynamics of linear and branched alkanes

Abstract

We have extended a recently introduced united atom model of n‐alkanes to investigate the liquid‐state dynamics of squalane, a molecule with six, symmetrically placed, methyl side groups. We compare our results with experimental measurements of diffusion in the same system and with experimental and simulation results on n‐decane and n‐tetracosane. The model reproduces the significantly different temperature dependence of diffusion in squalane and n‐alkanes of similar mass. The results of a detailed comparative study of the intrachain local dynamics in the different molecules makes apparent its correlation with global single‐chain relaxation processes. For linear alkanes, we also make a comparison between united atom and asymmetric united atom models.