Amplitude-modulated low-power decoupling sequences for fast magic-angle spinning NMR

We describe a heteronuclear low-power decoupling sequence for fast magic-angle-spinning NMR. The sequence dubbed as AM-XiX is related to XiX decoupling. Optimum decoupling parameters can easily be predicted from experimental settings. AM-XiX decoupling gives narrower lines than the low-power XiX scheme. It has comparable performance to other fully optimized low-power decoupling sequences, an improved offset behavior, and is particularly simple to set up. The coherence life times at 90 kHz MAS and 12 kHz decoupling are comparable to those obtained with high-power decoupling at 400 kHz field strength and 10 kHz MAS frequency.