Interlayer jump diffusion in the smectic-C*A phase by angular-dependent NMR study.
A detailed 2H nuclear magnetic resonance (NMR) study at 61.4 MHz of two chiral smectic C phases of a smectogen 10B1M7, one ferroelectric (SmC*) and the other antiferroelectric (SmC), is reported. Simulation of angular-dependent spectral patterns and/or signal intensities of the methyl deuterons are shown to provide information on the synclinic or anticlinic ordering, as well as the jump diffusion rates at different temperatures in the SmC phase. The molecular self-diffusion constant is determined to be in the range of 0.2-1.2 x 10(-14) m2/s over the temperature range of the SmC phase. Molecular self-diffusion in the SmC* phase should be faster, but remains undetectable by the present approach. Furthermore, the phase biaxiality in these phases is found to be vanishingly small. The critical magnetic field for unwinding the helical structure of 10B1M7 is found to be relatively high.
Xu
J
J
Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2.
Veracini
C A
CA
Dong
Ronald Y
RY