Brownian dynamics simulation of alkane chain reorientation: A comparison of models

Orientational time correlation functions and correlation times are determined using a Brownian dynamics and rigid body formalism and are compared with the results obtained from our previous Mori approach. It is found that the Mori method equipped with a minimum set of primary variables approximately represents the freely rotating chain. The correlation functions obtained from Brownian dynamics were found to display a rapid initial decrease, followed by a slow nearly exponential fall-off. First and second rank correlation times for pentane, hexane, nonane, and undecane are reported.