Rotational Relaxation in Fluids

Abstract
In this paper a number of expressions for angular momentum and reorientation correlation times are obtained. The inverse of the angular momentum correlation time is related to a sum of two terms, one of which involves the shear viscosity of the medium and the other of which describes the precessional relaxation of the molecule. The derivation is based on the similarity of the time dependences of the torque and the force exerted on the molecule of interest. The reorientation correlation time is related to the angular momentum relaxation time in the diffusion and the near‐diffusion limits. The expressions obtained here have been confirmed by a number of ESR experiments.