Deuteron NMR lineshapes in the antiferroelectric liquid crystalline phase of MHPOBC

The deuteron NMR lineshapes in the tilted antiferroeelectric smectic liquid crystalline phases are evaluated for: i) the case of a discrete short pitc h modulation P-1 = N.d where N = 2, 3, 4, ii) for a superposition of two mo dulations p(1) and p(0) where po much greater than p(0) as well as iii) for the case where in addition rapid molecular exchange between adjacent layer s takes place due to translational diffusion. The results are compared with the experimental deuteron NMR spectra of alpha-CD2 deuterated MHPOBC in th e Sm C-A* phase measured at different angles between the magnetic field dir ection and the normals to the smectic layers. The alternating tilt structur e of the Sm C-A* phase is confirmed.