Probing the quenching of rotary resonance by PISSARRO decoupling

Solid-state NMR experiments may suffer from rotary resonance recoupling ( R3) due to the interference between sample spinning at a frequency νrot and rf irradiation with an amplitude ν1H in the vicinity of harmonic relationships ν1H=nν where n = 1 or 2. Until recently, only the use of very high rf amplitudes (e.g., ν1H≫2ν) made it possible to avoid such interference effects. With the advent of PISSARRO decoupling, the deleterious effects of rotary resonance recoupling can be quenched, notably for ν1H=2ν, so that demands on the rf amplitude ν1H are relaxed. Here, we discuss how PISSARRO decoupling benefits from mirror symmetry and phase-shifting. We also show that PISSARRO can cope with the chemical shift anisotropy of protons and with proton-proton dipolar interactions. PISSARRO is most effective for very fast spinning at very high static fields.