A proton and deuteron spin–lattice relaxation study of the partially deuterated nematogens PAA and MBBA

Autor:	Ronald Y. Dong, E. Tomchuk, J. J. Visintainer, An‐Li Kuo, Ernst Bock, David B. Dewey, Chas. G. Wade
Rok vydání:	1977
Předmět:	Proton Condensed matter physics Intermolecular force Relaxation (NMR) Spin–lattice relaxation General Physics and Astronomy Dielectric MBBA Spin–spin relaxation chemistry.chemical_compound chemistry Deuterium Physical and Theoretical Chemistry Atomic physics
Zdroj:	The Journal of Chemical Physics. 66:3343-3346
ISSN:	1089-7690 0021-9606
DOI:	10.1063/1.434418
Popis:	Proton spin–lattice relaxation times (T1) have been measured in methyl deuterated para‐azoxyanisole (PAA‐d6) and in ring deuterated para‐azoxyanisole (PAA‐d8) samples as functions of frequency and temperature. When compared with recent order fluctuation theory, the agreement between theory and experiment is not as satisfactory for the intermolecular contribution to the spin–lattice relaxation as for the intramolecular contribution. Deuteron spin–lattice relaxation times (T1Q) have also been measured in a ring deuterated p‐methoxybenzylidene p‐n‐butylaniline (MBBA‐d8) sample. The above order fluctuation theory fails to predict the observed temperature dependence and the observed frequency independence of T1Q if the correlation time τc for local motions is taken to be one‐third the dielectric relaxation time τD. However, a fair agreement is obtained if one uses τc= (1/100) τD, a value consistent with Ref. 6.
Databáze:	OpenAIRE
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