Nuclear magnetic double resonance based on strong rf magnetic-field-induced coupling between spin systems
The origin of the rf magnetic-field-induced coupling between spin systems is discussed. A new nuclear-double-resonance technique employing this coupling is proposed, which has particular value in measuring pure nuclear-quadrupole-resonance spectra of integer-spin nuclei by nuclear double resonance. The sensitivity of the new technique is discussed for the case of 1H-14N double resonance in zero static magnetic field, as well as for the case of nuclear double resonance in a strong static magnetic field and the case of nuclear quadrupole double resonance. The technique is illustrated by 1H-14N double resonance in thymine in zero static magnetic field and by 19F-23Na double resonance in NaF, by 1H-14N double resonance in NH4H2PO4, and by 1H-87Rb double resonance in RbH2PO4 in a strong static magnetic field.