Cross-precession induced by the average dipolar field in high-resolution NMR

We analyse the effect of the average dipolar field on an NMR J-doublet. This effect is twofold: an overall shift of the spectrum and a cross-precession between its components, which results in different intensities for these components, whose ratio depends on the pulse angle. Experiments on di-isopropyl ether at 500 MHz confirm these predictions. In a thin elongated sample, a maximum intensity ratio of 1.09 is observed.