Previously, it has been shown that the use of pulsed field gradiconfidence, NOE enhancements of as little as 0.02%, thus ents in one-dimensional NOE experiments results in spectra of extending the range of distances over which the NOE can much higher quality than it has previously been possible to record. be used in a qualitative way. In addition, the improved qual-Such high-quality spectra make it possible to measure, with comity of the data makes the measurement of NOE buildup plete confidence, very small NOE enhancements and also make it curves much more straightforward, extending the use of the straightforward to measure NOE buildup curves. In this paper, NOE as a quantitative tool. the spin dynamics behind these NOE experiments with gradients In this paper, we investigate the detailed spin dynamics are analyzed in detail; the effects of strong coupling and molecular underlying these new one-dimensional NOE experiments diffusion are also examined. It is also shown how the basic experiand show how they differ from conventional experiments. ments can be improved upon, in particular how unwanted anti-We also show how interference effects associated with phase contributions (SPT effects) can be eliminated entirely. Experimental illustrations of the various methods and improvements selective population transfer ( SPT ) and zero-quantum coare given and practical recommendations made as to how the herence can be eliminated. The effects of molecular diffuexperiments are best performed. ᭧ 1997 Academic Press sion and strong coupling are also considered. Finally, practical recommendations are made, and data illustrating the quality of both qualitative and quantitative measurements are shown.