PULSED-FIELD-GRADIENT STIMULATED-SPIN-ECHO NMR-STUDY OF ANISOTROPIC SELF-DIFFUSION IN SMECTIC AD LIQUID-CRYSTAL CBOOA

Anisotropic self-diffusion coefficient tensor was determined in the sm ectic Ad (S(Ad)) phase of a polar mesogen CBOOA. The pulsed-field-grad ient stimulated-spin-echo NMR technique was applied in combination wit h angular displacement of a quadrupole coil, to obtain the diffusion c oefficient components both parallel (D(parallel-to) and perpendicular (D(perpendicular-to)) to the director for the sample oriented at the m agic angle from the large magnetic field. It was found that D(parallel -to) > D(perpendicular-to) (D(parallel-to)/D(perpendicular-to) = 2.3-3 .0), and the activation energies were similar for the two components. Nematic-like diffusion characteristics have been revealed.