Unlike most other NMR experiments that correlate resonances via J-coupling through bonds, the NOESY experiment correlates resonances via cross-relaxation through space. Since the intensity of the correlation is strongly dependent on the distance between the interacting nuclei, the intensity of the NOE peak is related to the distance between the atoms. This makes the NOESY experiment very useful for determining three dimensional structures and assigning stereochemistry. However, interpreting NOESY spectra has to be done carefully, as artifacts due to zero-quantum transitions are often observed.
