Nuclear Magnetic Relaxation in the Presence of Paramagnetic Ions. II

Abstract

The influence of independent processes of relaxation of paramagnetic ions on nuclear magnetic relaxation in the presence of these ions is treated using the Kubo and Tomita method. The nuclei are assumed to relax as a result of their contact with the ions through isotropic spin-exchange coupling. The second-order terms in the perturbation expansion of the relaxation tensor yield contributions to the Bloch relaxation times of the nuclear spin system that agree with previous calculations by Solomon and Bloembergen. The fourth-order terms yield contributions to the nuclear relaxation times which are in agreement with the phenomenological relation suggested by Bloembergen and Morgan for this case, provided that the applied static field is not too strong and that the ionic motion can be described by a single Bloch relaxation time.