Off-resonance multiple-pulse dynamics in solid-state NMR spectroscopy: A revised coherent averaging theory analysis

The standard coherent averaging theory treatment of the resonance offset interaction is compared to exact calculations for multiple-pulse solid-state NMR experiments. Significant differences between coherent averaging approximations and exact results are revealed, even for idealized conditions. A revision of the standard analysis is proposed as a way of improving the description of the off-resonance dynamics in these experiments. We use the insights obtained from this investigation to derive a qualitatively new type of homonuclear decoupling sequence, and evaluate the performance and advantages of this sequence with both simulations and experimental tests. Copyright 1999 Academic Press.