Proton resonance for oscillating field of the order of static magnetic field.

A spin decoupling method in nuclear quadrupole resonance spin echo experiment is used to detect the proton magnetic resonance absorption spectrum. The behavior of proton resonance in alpha phase of polycrystalline p-dichlorobenzene as a function of the intensity of the proton decoupling oscillating field (H(2)) is measured. Good agreement between the experimental resonance frequency and Shirley's theory for a non-interacting 1/2 spin system is observed. To our knowledge this is the first time the NMR proton frequency dependence on linear polarized excitation field intensity for H(2)/H(o) as high as 1.8 is measured.