PITANSEMA, a low-power PISEMA solid-state NMR experiment

A low radio frequency power polarization inversion spin exchange at the magic angle (PISEMA) pulse sequence is described for the measurement of heteronuclear dipolar couplings from solids. The method employs a time averaged nutation concept to significantly reduce the rf power required to spin-lock low gamma nuclear spins in PISEMA experiments. The efficacy of the 2D method is demonstrated on a single crystal of n-acetyl-L-(15)N-valyl-L-(15)N-leucine dipeptide to measure (1)H-(15)N dipolar couplings and a liquid crystal sample to measure (1)H-(13)C dipolar couplings.