NUCLEAR-SPIN DYNAMICS (I=1/2) UNDER THE INFLUENCE OF RANDOM PERTURBATION FIELDS IN THE STRONG COLLISION APPROXIMATION

We investigate the relaxation of a spin 1/2 system by random perturbation fields in the strong collision approximation. In contrast to prior studies no assumptions are made about the fluctuation frequency or about the magnitude of the perturbation fields. A general result for the Laplace transform of the spin lattice and phase relaxation is derived. We discuss the result for phase relaxation induced by a perturbation field with only two opposite modes along the x, v and z axis. Using the method of the general moment approximation we demonstrate how the spin lattice relaxation can be approximated by a sum of exponentials, and we discuss approximations by a single exponential and a bi-exponential function.