Rotational-Echo, Double-Resonance NMR

Rotational-echo, double-resonance (REDOR) NMR is a high-resolution, solid-state NMR experiment for measuring the dipolar coupling between a heteronuclear spin pair [1,2]. The 1/r³ distance dependence of the dipolar coupling makes REDOR useful for the structural characterization of solids, and REDOR has become a valuable tool for characterizing a wide range of materials, including peptides and proteins, polymers, zeolites, guest-host systems, glasses, and more. Since the REDOR experiment is based primarily on trains of π pulses, it has mostly been used to measure dipolar couplings between pairs of spin -1/2 nuclei. Under certain conditions, however, the REDOR experiment can also make effective use of quadrupolar nuclei as structural probes.