ON THE DETECTION OF 2ND-ORDER DIRECTOR FLUCTUATIONS AT A STANDARD HIGH-FIELD BY SPIN-SPIN RELAXATION

We report measurements of the deuteron spin-spin relaxation time T-2 i n the nematic phase of p-methoxybenzylidene-p-n-butylaniline using the quadrupolar echo pulse train in a magnetic field of 7 T. The derived zero-frequency spectral densities J(0)(0) at different carbon sites, u nlike the J(1)(omega(0)) and J(2)(2 omega(0)), could not be interprete d using molecular reorientation and internal bond rotations in the but yl chain. It is shown that experimental T-2 data at a high magnetic fi eld could be used to gain information on second-order director fluctua tions.