Relaxation of magnetization after a pulse

Measurements of Ti can be used to learn something about the mobility of molecules, and also about the relative mobilities of different parts of bigger molecules. The ends of a long chain in a molecule are more mobile than the middle. Measurements of Ti for Si have, for instance, been used to study the mobility of 

Relaxation of the transverse magnetization My after a 90° pulse illustrated in two time steps. 

Schematic illustration of the dependence of the relaxation times Ti and T2 on the molecular tumbling rates, expressed in terms of reciprocal correlation time.  

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