Effects of intermolecular dipolar couplings in solution NMR in separated time intervals: the competition for coherence transfer pathways

We investigate the competition between intermolecular dipolar effects in multiple time intervals and develop a theoretical framework to understand coherence transfer when this competition is important. The quantum picture permits explicit evaluation of coherence transfer pathways, which have been verified by experimental data obtained from pulse sequences with multiple-quantum selective phase cycling. Implications for sequences in common use in biological applications are discussed. (C) 1998. Published by Elsevier Science B.V. All rights reserved.