A new approach to the extraction of dynamic information from the analysis of 2H NMR relaxation times in tilted chiral mesophases

A new approach to analyze 2H spin-lattice relaxation times in tilted smectic phases in terms of dynamic parameters for individual molecular and internal motions is reported. Such analysis, commonly applied to uniaxial phases, could not be extended so far to chiral smectic phases for both experimental and theoretical reasons. These problems have been here overcome neglecting the dependence of spectral densities on the azimuthal angle φ, and adopting a global target approach. In this way, the existing diffusional models can be used to determine dynamic parameters in chiral smectic C phases. An application to the ferroelectric mesogen 8BEF5 is reported.