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In this report the translational self-diffusion behavior of calamitic mesogens in smectic phases measured by means of NMR diffusometry will be reviewed. In particular the results reported demonstrate that translational diffusion in smectic phases is strongly dependent on molecular packing in the layered structure, but, in contrast with previous assertions seems to be only slightly affected by the clinicity of the phases, i.e., supporting the second order character of the phase transition going from the synclinic to the anticlinic structure typical in chiral Smectic C* phases. [ABSTRACT FROM AUTHOR]

Deuterium NMR spectroscopy is used to study a ring-deuteriated chiral liquid crystal 4-(2-methylbutyl)oxycarbonylphenyl 4-(10-undecenyloxy)benzoate. The quadrupolar and proton-deuteron dipolar splittings, and deuteron quadrupolar and Zeeman spin-lattice relaxation times were measured as a function of temperature in the smectic A phase at two different Larmor frequencies. The derived spectral densities of motion at different temperatures were analysed simultaneously using a rotational diffusion model which also includes internal ring rotations. Motional parameters (D, D[sub ||] , D[sub R] ) and order parameter tensors (S, S-S) were obtained. Although the present data seem insufficient to draw a definitive conclusion, we believe that it is possible for this particular chiral molecule to have D>D, which is different from non-chiral rod-like liquid crystals. [ABSTRACT FROM AUTHOR]

[sup 2] H NMR spectroscopy is employed to investigate the orientational order, molecular structure and phase transitions of the chiral smectic liquid crystal 1-methylheptyl 4'-(4-n-decyloxybenzoyloxy)biphenyl-4-carboxylate (10B1M7), showing smectic A, C* and J phases, as well as several sub-smectic C* phases. Two optically pure, differently deuteriated isotopomers have been purposely synthesized and studied. [ABSTRACT FROM AUTHOR]