Triply compensated RF pulses in high-resolution NMR spectroscopy

In spite of the advancements in NMR pulse sequence design, high-fidelity control of nuclear spins using RF pulses is still problematic. With the advent of ultra-high field spectrometers, the effects of these imperfections are even more significant. Triply compensated RF pulses enable high-fidelity control of spin operations at bandwidths larger than conventional experiments. This family of pulses is time-optimized and performs universal π and π/2 operations with simultaneous compensation for spatial RF inhomogeneity and heteronuclear J coupling evolution. Here, we describe how to design triply compensated pulses using genetic algorithm (GA) optimization and illustrate a few examples, showing their impact on the sensitivity of double-and triple-resonance NMR experiments.