Measurement of cross relaxation rates between selected nucleus pairs in NMR spectroscopy

This method measures cross relaxation rates in highly resolving NMR spectroscopy, where the sample substance is dissolved in a liq. and has nuclei A and X which have different chem. shifts WA and WX in a homogeneous static magnetic field Bo in the direction of the z-axis. The orientation of the longitudinal components I2A and I2X bring about the magnetization vectors IA and IX of the nuclei A and X during a time interval tan and irradn. with a constructed high-frequency field. Subsequently a longitudinal magnetization is conducted through a suitable high-frequency pulse sequence in a transverse magnetization which produces a high-frequency signal which is sensed by a detector. The constructed high-frequency field is formed from >=2 weak selective partial fields which have selected frequencies such that the magnetization vectors IA and IX are mixed in a synchronous mutation motion for all remaining nuclear spin remaining unaffected for the sample substance. Through the difference of the decay rates, the cross relaxation rates are detd. and from this the internuclear distance between the chosen nuclei. [on SciFinder (R)]