Deuteron spin-lattice relaxation mechanisms in partially deuterated nematic MBBA

Abstract

The frequency and temperature dependence of the spin-lattice relaxation time, T ₁, of the various benzene ring deuterons in partially deuterated p-methoxybenzylidene-p-n-butylaniline have been measured. It was found that in the nematic phase the deuteron T ₁ is independent of frequency between 4 and 41 MHz and thermally activated. The results seem to demonstrate that benzene ring rotation is the dominant deuteron relaxation mechanism in the MHz region and that the aniline and benzylidene rings reorient at different rates around the para axes.