Nuclear Magnetic Double Resonance with an Incoherent Radio-Frequency Field

Abstract

The decoupling of heteronuclear spin systems by means of a strong irradiation of rf magnetic random noise is explored theoretically and experimentally. It is shown that it is feasible to eliminate simultaneously all splittings due to one or more nuclear species. Double resonance with random noise is of particular advantage if the resonance frequencies of the nuclei causing the splittings cover a wide spectral range and if, at the same time, the couplings are relatively weak. In the case of a narrow spectral range and strong couplings, double resonance with a coherently frequency-modulated rf field can give comparable decoupling effects. Double resonance with random noise has a strong similarity to the effects of chemical exchange and relaxation.