Techniques for Determining Relaxation Times and Motional

TECHNIQUES FOR DETERMINING RELAXATION TIMES AND MOTIONAL PARAMETERS 

Since the NMR experiment is essentially tuned to one type of nucleus it is usually a relatively easy matter to distinguish atomic motion of the different constituents of a material. Each will have its own relaxation parameters which will depend on the local environment of the nucleus and which can therefore be investigated separately. The power of NMR for microdynamics studies lies in the wide range of frequencies that can be investigated non-destructively and under many environmental variations, including temperatures from sub-Kelvin to 2000K. 

There are several ways of determining T, the most reliable method probably being saturation-recovery, in which two 90° pulses are applied separated by a time x of the order of Ti. The signal height is then proportional to Mz(x), given by 

2 Other spin-lattice relaxation times (TipTjo) 

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