Temperature-dependent statistical theory of cross relaxation in nickel-sodium triacetylacetonate dioxane

A temperature-dependent statistical theory of two- and three-spin cross relaxation processes is developed for S=1 paramagnetic ions. It takes account of fluctuations of magnetic quantum numbers of the ions due to spin-spin and spin-lattice interactions in terms of the ensemble theory of statistical mechanics. Explicit two- and three-spin resonant cross relaxation rates are computed for Ni2+ ions in the diamagnetic host lattice of dioxane and compared with experimental results. Reasonably good agreement is obtained with experiment, both with regard to temperature dependence and the actual magnitudes of two- and three-spin cross relaxation rates.