LOCAL COORDINATION OF EUROPIUM(III) IN POLY(ETHYLENE OXIDE) AND POLY(PROPYLENE OXIDE)

The luminescence spectra of (PEO/PPO)(n)EuBr3, with n = 3-80, were recorded and the corresponding excitation and emission lines assigned to the F-7(0-2) --> (5)G(J), (5)L(6), D-5(0-4) and to the D-5(0.1) --> F-7(0.4) transitions, respectively. The emission energies were used for investigating the local coordination of europium(III) in these polymer electrolytes. The nearest ligands charge distribution was specified in terms of a mean radius for the Eu3+ first coordination shell, and the results found for different concentrations of the ion, 2.3-2.7 Angstrom, are compatible with known data. The local-field interaction model, the polarization behavior of the D-5(0) --> F-7(0) transition, certain moment operators, and the optical activity of the F-7(2,3,4) components, permitted to assign the approximate local symmetry of the EU(3+) in PEO/PPO electrolytes to the C-2v point group.