Nuclear magnetic resonance of oriented nuclei. 2. Transient methods

In this chapter some transient nuclear magnetic resonance methods in oriented nuclei are discussed. A brief treatise is given of general NMR-ON theory. Some fixed-frequency NMR-ON techniques are discussed in which pulsed RF fields with a constant RF frequency are employed, such as one-, two- and more pulse and spin-echo experiments. Adiabatic fast passage NMR-ON is described, in which the RF frequency is uniformly swept in across a resonance in a time which is short compared with the spin-relaxation time, but sufficiently long that throughout the passage, the angular velocity of rotation of the effective magnetic field in the Larmor frame is much smaller than the precessional frequency of the nuclei about this field. The pulsed FM-NMR-ON technique is discussed. Finally a brief treatise is given of the study of resonant cross-relaxation between dissimilar nuclei in a ferromagnetic host, as an application of transient NMR-ON. (Auth.)