AN EPR STUDY OF A SMECTIC <i>C</i> LIQUID CRYSTAL: A NEW METHOD FOR DETERMINING THE TILT ANGLE

Abstract

We have aligned the liquid crystal molecules of 4, 4′-di-n-heptyloxyazoxybenzene in the smectic C mesophase by means of a magnetic field. With the aid of a paramagnetic probe, we have studied the effect of rotation of the aligned sample in the magnetic field of the EPR spectrometer. Interpretation of the results enables us to determine the tilt angle of the liquid crystal, and to predict that smectic C liquid crystals would not lend themselves to NMR orientation studies because of molecular reorientations.