Demagnetizing field effects on the Hahn echo

Strong effects of modulated demagnetizing fields on the attenuation of Hahn echoes in liquids are shown theoretically as well as experimentally. As such demagnetizing fields are the basis of non-linear evolution leading to multiple echoes, it follows that the dominating nature of such echo signals is of a purely single-quantum character. It is concluded that the contribution of intermolecular multiple-quantum coherence transfer echoes to the multiple echoes is negligible. The effects shown in this study are of major impact for NMR spectroscopy with high-field instruments as they nowadays are in ubiquitous use. (C) 2000 Published by Elsevier Science B.V. All rights reserved.