Comparison of the dielectric and NMR results for liquid crystals: dynamic aspects

Critical analysis of the results of studies of molecular rotational dynamics in liquid crystalline substances with the aid of the dielectric spectroscopy (DS) and nuclear magnetic resonance (NMR) is given. Both methods are known to be sensitive to different aspects of molecular rotations: the polarization vector and the relaxation time τ DS in the case of DS, a tensor describing a nuclear interaction and the correlation time τ NMR for NMR method. Furthermore, both methods provide correlation functions with different rank values. A common basis for the comparison between τ DS and τ NMR is postulated. Several examples of the temperature dependence of the correlation times coming from the two spectroscopic methods are presented. Qualitative agreements of the correlation times were achieved in most cases. Copyright © 2014 John Wiley & Sons, Ltd.