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Sideband patterns from rotor-encoded longitudinal magnetization in MAS recoupling experiments.

S M De Paul·K Saalwächter·R Graf·H W Spiess
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Abstract

Recent multiple-quantum MAS NMR experiments have shown that a change in the rotor phase (and, hence, in the Hamiltonian) between the excitation and reconversion periods can lead to informative spinning-sideband patterns. However, such "rotor encoding" is not limited to multiple-quantum experiments. Here it is shown that longitudinal magnetization can also be rotor-encoded. Both homonuclear and heteronuclear rotor encoding of longitudinal magnetization (RELM) experiments are performed on dipolar-coupled spin-1/2 systems, and the corresponding sideband patterns in the indirect dimension are analyzed. In both cases, only even-order sidebands are produced, and their intensity distribution depends on the durations of the recoupling periods. In heteronuclear experiments using REDOR-type recoupling, purely dipolar sideband patterns that are entirely free of effects due to the chemical-shielding anisotropy can be generated. Advantages and disadvantages of the heteronuclear RELM experiment are discussed in the context of other methods used to measure heteronuclear dipolar couplings.

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AlanineAnisotropyMagnetic Resonance SpectroscopyTrichloroacetic AcidTyrosineJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.

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S M De Paul, K Saalwächter, R Graf, H W Spiess. 2000. Sideband patterns from rotor-encoded longitudinal magnetization in MAS recoupling experiments.. https://doi.org/10.1006/jmre.2000.2119

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