Rotational relaxation of OCS in n-alkanes: Collective and collisional effects

Abstract

The rotational relaxation time τ l R of OCS in liquid n‐dodecane is determined at several temperatures by means of infrared and isotropic Raman measurements. The results are compared with data on OCS in other n‐alkanes and are interpreted in terms of hydrodynamictheories as well as of the theory of Hynes et al. The latter theory explains well our results and shows the predominance of collisional over collective effects. In this case, a simple cage model accounts for all results and displays the dominant role of the relative free volume.