Narrowing in Spin Space - WAHUHA

Sample spinning induces a time dependent effect on the relationship between a nuclear spin fixed along Hq and its 

Clasically, when an rf pulse is applied, e.g. along the x axis, this rf field, Hj, will cause the net spin magnetization, M, aligned along Hq to process as shown in Fig. 4a. A pulse of specific duration for a given will cause M to process 

The same type of pulse sequence can be applied along the y axis, rotating M into the x axis. By proper use of pulses and delays, M can be made to spend equal amounts of time on each of the rotating frame axes. As can be seen, this mimics in spin space the results obtained by sample rotation in real space. The necessary pulses are diagramed in Fig. 4d. If the pulses are short enough and the delays, T, are kept to a minimum, the rotation rate of the process can be made fast 

Finally, it should be pointed out that the above discussions are vast over-simplifications which are (hopefully) conceptually easy to grasp. Unfortunately, they are not theoretically satisfying. Additional reading is urged to provide a more indepth understanding(1-5). 

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