13C NMR study of orientational ordering in smectic A phase of chiral liquid crystals

Carbon-13 NMR spectroscopy is used to probe the orientational ordering in the smectic A phase of a chiral liquid crystal. Quantitative analyses of the chemical shifts and dipolar splittings of the aromatic carbons enable us to obtain the location of the long molecular axis of the molecular core and its molecular order parameters S00, S02 in the smectic A phase. The results from different NMR methods show self consistency and further demonstrate the general methodology of 13C NMR for the determination of orientational ordering in liquid crystals.