2H-NMR spectroscopy is employed to investigate the orientational order in the nematic and smectic A, B, and crystal G phases formed by 4-(2-methylbuty1)phenyl 4'n-heptylbiphenyl- 4-carboxylate-d18. Evidence of the lock in the trans-conformation of the first two mcthylene groups of the n-heptyl chain is found in the SBand G phases. The dynamics of the aromatic molecular core are studied in a temperature interval including the SA-SBtransition, by the analysis of the deuterium Zeeman and Quadrupolar relaxation times using the rotational diffusion model. Hence the diffusion constants related to the molecular spinning and tumbling motions are evaluated. © 2006 Taylor & Francis.
A2h nmr study of orientational order, phase transitions and dynamics in a liquid crystalline compound
CATALANO, DAVIDE;FORTE, CARLO;Imbardelli, D.
1996-01-01
Abstract
2H-NMR spectroscopy is employed to investigate the orientational order in the nematic and smectic A, B, and crystal G phases formed by 4-(2-methylbuty1)phenyl 4'n-heptylbiphenyl- 4-carboxylate-d18. Evidence of the lock in the trans-conformation of the first two mcthylene groups of the n-heptyl chain is found in the SBand G phases. The dynamics of the aromatic molecular core are studied in a temperature interval including the SA-SBtransition, by the analysis of the deuterium Zeeman and Quadrupolar relaxation times using the rotational diffusion model. Hence the diffusion constants related to the molecular spinning and tumbling motions are evaluated. © 2006 Taylor & Francis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
