Motional narrowing under diffusion of two spin sub-lattices in LiNaSO4.
An expression for the dipolar correlation function characterizing the fluctuations of the Hamiltonian under uncorrelated diffusion of two cationic sub-lattices in a solid has been obtained. A corresponding formula, which can be used for fitting the two-step temperature dependencies of the NMR line width, has been deduced. We also considered the case of a distribution of correlation times and deduced a corresponding analytical fitting function. Elaborated expressions have been applied to the NMR line width analysis of LiNaSO4 in the temperature range 295-788 K.
CNRS, CEMHTI UPR 3079, Univ. Orléans, F-45071 Orléans, France. Electronic address: roman.shakhovoy@cnrs-orleans.fr.
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Shakhovoy
CNRS, CEMHTI UPR 3079, Univ. Orléans, F-45071 Orléans, France.
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Deschamps
CNRS, CEMHTI UPR 3079, Univ. Orléans, F-45071 Orléans, France.
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Rakhmatullin
CNRS, CEMHTI UPR 3079, Univ. Orléans, F-45071 Orléans, France.
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Sarou-Kanian
CNRS, CEMHTI UPR 3079, Univ. Orléans, F-45071 Orléans, France.
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P
Florian
CNRS, CEMHTI UPR 3079, Univ. Orléans, F-45071 Orléans, France.
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Bessada
Lithium sodium sulfate; Motional narrowing; NMR; Non-exponential correlation function