Effects of Perturbations on Phosphorescence: Luminescence of Metal Organic Complexes

Fluorescence and phosphorescence spectra, phosphorescence lifetimes, and relative ratios of intensities of fluorescence to phosphorescence of the dibenzoylmethane derivatives of the trivalent ions of Al, Sc, Y, La, Gd, and Lu have been measured. The lifetimes and intensity ratios of the various compounds differ widely, while the spectra are very similar. For instance, although the Lu and Gd compounds have practically indistinguishable phosphorescent spectra, the lifetimes of their phosphorescences differ by a factor of fifty. The results are interpreted in terms of Lewis's triplet theory of the phosphorescent state and spin-orbit perturbation of the levels. The largest effect is produced by the paramagnetic gadolinium ion. The effects produced by the non-magnetic ions depend on their nuclear charge and on their electronic structure.