Relationship of the ratio of the band intensities of luminescence spectra of lanthanide ions in solutions of their complexes with the polarizability of the ligand molcules

The ratio of the band intensities of the luminescence spectra of lanthanide ions (Ln) - which equals one, corresponding to the so-called ''supersensitive'' transition (SST) (with a difference of the quantum numbers J of the electronic states ΔJ = 2), and the other which does not correspond to it or which corresponds to the magnetic dipole transition - is an important value which is dependent on the environment of Ln3+. For a number of europium complexes such values, denoted in the sequel by n, have been determined in prior work, in which references are given to still earlier studies. The values of n for Eu in a series of glasses are available. A correlation has been established between the values of n for Sm3+ and Eu3+ and the intensity of the absorption bands, established by the oscillator strenghts (P) of Nd3+ ions in solutions of analogous complexes; a similar dependence is found between the values of n for Tb and Dy and the P values in solutions of Ho3+ complexes. It has been found that the value of n increases in the majority of cases in direct proportion of the number of coordinated ligands. The ratios of the band intensities of the luminescence spectra depend also on the type of solvent in which the complexes are dissolved and grow with increase in its dielectric constant