Quadrupolar echo double resonance (QEDOR) and solid echo double resonance (SOLEDOR) NMR

We propose two new double resonance experiments that are sensitive to internuclear dipolar couplings, namely Quadrupolar Echo DOuble Resonance (QEDOR) and SOLid Echo DOuble Resonance (SOLEDOR). The experiments are explained by analysis of the spin evolution during the pulse sequences, and are demonstrated for deuterium–proton double resonance experiments with partially deuterated polycrystalline glycine. In addition to molecular dynamics information normally obtained from the standard quadrupolar echo experiment, the QEDOR experiment is able to provide information about the local molecular surroundings by probing heteronuclear dipolar interactions. We have illustrated this with experiments on single-phase and phase-separated samples of tetrahydrofuran clathrate hydrate.