An improved broadband decoupling sequence for liquid crystals and solids

Recently we developed an efficient broadband decoupling sequence called SPA RC-16 for liquid crystals [J, Magn. Reson. 130, 317 (1998)]. The sequence i s based upon a 16-step phase cycling of the 2-step TPPM decoupling method f or solids [J. Chem. Phys. 103, 6951 (1995)]. Since then, we have found that a stepwise variation of the phase angle in the TPPM sequence offers even b etter results. The application of this new method to a liquid crystalline c ompound, 4-n-pentyl-4'-cyanobiphenyl, and a solid, L-tyrosine hydrochloride , is reported. The reason for the improvement is explained by an analysis o f the problem in the rotating frame. (C) 2000 Academic Press.