Magnetic field-cycling investigations of molecular tunnelling

Some applications of magnetic field-cycling NMR in the study of molecular tunnelling are reviewed with selected examples. Experiments on the rotational tunnelling of methyl groups describe the techniques that are available for studying coherent tunnelling. The case of incoherent phonon-assisted tunnelling is described in the context of proton transfer in the hydrogen bond. The importance of developing broadband techniques in NMR is emphasised.