Multiple chemical shift precession

Evolution of multiple quantum coherence (of order p) is treated as successive evolution of each of the p chemical shifts. As expected, double quantum coherence precesses at wt + cos, and zero quantum coherence precesses at (i)j — 0)s. As we noted in Section 11.5, such coherences are not affected by spin coupling. 

Filter elements have been developed, not just for coupling evolution, but also for chemical shift selection [5.215 - 5.221]. An early example was the jump-return method for solvent signal suppression. Check it 5.2.3.3, whereby the resonances at a given chemical shift and related multiples were suppressed. In common with the z-filter for zero-quantum suppression, the CSSF (Chemical 5hift iSelective Filter) element uses different free precession periods to give varying degrees of chemical shift evolution for each scan in a multiple scan experiment. 

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