A detailed theoretical and experimental study has been completed of the absorption and dispersion mode nuclear magnetic resonance signals for Li 7 in solid lithium metal at room temperature. Calculations of resonance signal shapes, based on the Bloch Theory as modified by the small-amplitude modulation theory of Halbach, were made with an IBM 650 computer and were compared with the experimental results. A variety of experimental conditions and both the in-phase and quadrature components of the signal at the modulation frequency were studied. The Bloch-Halbach Theory appears to account very satisfactorily for the saturation behavior of the four types of resonance signals. In addition, the behavior of the complex absorption mode signal provides a convenient means of determining with precision the location of the quadrature phase signal.
Torgeson, D. R.; Jones, W. H. Jr.; and Barnes, R. G., "Steady-state nuclear induction signal shapes in lithium metal" (1960). Ames Laboratory Technical Reports. 42.