Orientational dynamics of non-rigid three-bond chains

Abstract

A diffusion equation for a stiff chain has been applied to a calculation of first rank orientational correlation functions of flexible three-bond molecules. The non-linear equations for the bond vectors are reduced to a set of linear equations for the bond vector correlation functions by means of the Mori method. Orientational correlation times and Cole-Cole plots are calculated for the three-bond chain as a consequence of the potential hindering internal rotation. It is found that the correlation times in these small chains are anisotropic and depend significantly on the location of the vectors in the molecule. Cole-Cole plots for certain modes are skewed arcs, even in this diffusion picture, as a consequence of the three rigid-body correlation times and the extra time constants introduced by the internal degree of freedom.