Influence of molecular rotation on some physical properties of liquids

Abstract

In those liquids which show an Arrhenius temperature dependence of viscosity, molecules are able to rotate many times about at least two axes during the time between translational jumps. In the higher temperature non-Arrhenius region molecules can rotate about only one axis during this time, while in the lower temperature non-Arrhenius region molecular rotation occurs primarily as a result of translational motion. The distribution of shear relaxation times in liquids at low temperatures arises from this restriction of molecular rotation, as does the structural contribution to the heat capacity of non-associated liquids.