Saturation of a spin system with a nonequidistant spectrum in a solid

The saturation of a nonequidistant spin system is analyzed for the example of spin-5/2 nuclear quadrupole resonance in a molecular crystal; nonequilibrium states of the dipole-dipole reservoir are taken into account. The Zubarev method of a nonequilibrium statistical operator is used to derive equations generalizing the phenomenological balance equations for the populations in the case of a solid with strong magnetic dipole-dipole interactions. The real and imaginary parts of the dynamic susceptibility of the system, '-ⁱ, are found.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 41–45, May, 1974.