Sensitivity improvement during heteronuclear spin decoupling in solid-state nuclear magnetic resonance experiments at high spinning frequencies and moderate radio-frequency amplitudes

Searching for optimal conditions during one- and multi-dimensional solid-state NMR experiments in high static fields may require spinning the sample at frequencies above 40 kHz. This implies challenging requirements for heteronuclear spin decoupling. We have compared the performance of the latest heteronuclear decoupling schemes at high magic-angle spinning frequencies. The results demonstrate that at commonly used rf amplitudes between 80 and 120 kHz, PISSARRO decoupling provides substantial sensitivity improvement. The performance of low-amplitude decoupling at different spinning speeds is also compared and its dependence on the inherent inhomogeneity of the rf field is probed by numerical simulations.