Double resonance interferometry: Relaxation times for dipolar forbidden transitions and off-resonance effects in an AX spin system

Experimental and theoretical results of a nuclear magnetic double resonance interferometric study of a model AX spin system are presented. Measurements of the characteristic relaxation times of off-diagonal density matrix elements corresponding to magnetic-dipole-forbidden transitions are presented, and the use of such relaxation time constants to obtain information including cross correlations of the fluctuating fields at the A and X nuclear sites is discussed. Off-resonance effects produce large changes in the spectra, and exploitation of these effects to indirectly measure the precise resonance frequency of a spin with a small magnetogyric ratio is discussed.