In this article we report a dynamics investigation of two chiral smectogens
, 1-methylheptyl 4'-(4 " -n-decyloxybenzoyloxy)biphenyl-4-carboxylate (10B1
M7) and [4-(2-methylbutyloxycarbonyl)phenyl] 4-n-heptyl-biphenyl carboxylat
e (MBHB), whose structural and ordering properties were studied previously
by our group. The deuterium Zeeman (T-1Z) and quadrupolar (T-1Q) spin-latti
ce relaxation times of two differently deuterated isotopomers of 10B1M7 and
one of MBHB have been measured across the whole mesophasic range by means
of the broadband Jeener-Broekaert pulse sequence. The trends against temper
ature of the spectral densities obtained from the relaxation times have bee
n discussed qualitatively in the phases in which the molecules do not align
along the external magnetic field, whereas a quantitative interpretation i
n terms of diffusion coefficients of internal and overall molecular motions
has been attempted for the smectic phases for which theoretical models wer
e available. The results obtained for the two smectogens are discussed and
compared with those of other smectogens reported in the literature.