Homonuclear dipolar decoupling under fast MAS: Resolution patterns and simple optimization strategy

A simple method is shown for optimization of 1H homonuclear dipolar decoupling at MAS rates exceeding 10 kHz. By monitoring the intensity of a spin-echo under the decoupling conditions, it is possible to optimize the amplitude of the RF magnetic field, the cycle time of the decoupling sequence and the resonance offset within minutes. As a result, the decoupling efficiency can be quickly and reliably fine-tuned without using a reference sample. The utility of this method has been confirmed by studying the resolution patterns for the supercycled PMLG scheme, which were found to be in excellent agreement with earlier theoretical predictions and verified in high-resolution 2D 1H-1H experiments.