Fraction of mobile segments

Number of accessible orientations, and fraction of mobile segments... 

The new NMR methods reviewed here enable the quantification of dynamics in unlabeled complex organic materials, which were previously inaccessible to such studies without isotopic enrichment. The new techniques make it possible to characterize segmental motions, with correlation times ranging from < 10 6 s to 10 s, quantitatively in terms of the motional amplitude and geometry, the number of orientational sites accessible to the moving segments, and the fraction of mobile segments. 

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