Translational Self-Diffusion in the Smectic A Phase

Abstract

The translational self-diffusion tensor of smetic A liquid crystals is obtained in the hydrodynamic limit of the two fluid model. The diagonalized matrix elements are calculated by utilizing Rice and Kirkwood's intermolecular correlation equation for the friction constant and Einstein's relation for diffusivity. McMillan's potential for the smectic A phase is used in calculations. The anaharmonic effects are taken into consideration in the preferred direction of molecular alignment. The results are qualitatively compared with a spin echo measurement reported by Krüger et al.