STUDY OF THE MOLECULAR-DYNAMICS FROM DEUTERIUM ZEEMAN AND QUADRUPOLAR NMR RELAXATION OF 4,4'-DI-N-HEPTYLAZOXYBENZENE IN THE NEMATIC AND SMECTIC-A PHASES

被引：10
|
作者：
FORTE, C
GEPPI, M
VERACINI, CA
机构：
[1] CNR,IST CHIM QUANTIST & ENERGET MOLEC,V RISORGIMENTO 35,I-56100 PISA,ITALY
[2] UNIV PISA,DIPARTIMENTO CHIM & CHIM IND,I-56100 PISA,ITALY
来源：
ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES | 1994年 / 49卷 / 1-2期
关键词：
LIQUID CRYSTAL; DEUTERIUM NMR; MOLECULAR DYNAMICS; DEUTERIUM RELAXATION; DIRECTOR FLUCTUATION;
D O I：
10.1515/zna-1994-1-246
中图分类号：
O64 [物理化学（理论化学）、化学物理学];
学科分类号：
070304 ; 081704 ;
摘要：
The deuterium spin-lattice (Tz) and quadrupolar (T1Q) relaxation times of the liquid crystal 4,4'-Heptyl-azoxybenzene (HAB), deuterated on the aromatic rings and the first methylene group of the chains, have been measured by means of the Jeener-Brockaert pulse sequence at two different frequencies (10 and 46.04 MHz) and throughout the nematic and the smectic A phase. By applying suitable models, we have deter-mined rotational and reorientational diffusion coefficients and evaluated the contribution of the different motions (internal, molecular and collective) to the relaxation. In particular we have found a non negligible contribution from order director fluctuations. A comparison between the T1Z and T1Q measurements performed by means of Jeener-Broekaert and Wimperis pulse sequences is also shown.
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页码：311 / 319
页数：9
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