Photoacoustic spectroscopy study on lanthanide ternary complexes with dibenzoylmethide and phenanthroline

The photoacoustic (PA) spectra of Eu(Dbm)(3).Phen and coprecipitates Eu(0.8 )Ln(0.2)(Dbm)(3).Phen complexes (Ln(3+): Nd3+, Gd3+, Tb3+; Dbm: dibenzoylme thide; Phen: phenanthroline) are reported. The PA intensity in the region o f the ligand absorption increases for Eu0.8Gd0.2(Dbm)(3).Phen, Eu0.8Tb0.2(D bm)(3).Phen, Eu(Dbm)(3).Phen and Eu0.8Nd0.2(Dbm)(3).Phen, respectively. It is indicated that additions of the second lanthanide ions change the relaxa tion processes of the complexes. The changes of fluorescence spectra turn o ut to be complementary to the PA spectra. The intramolecular energy transfe r and intermolecular energy transfer processes in the coprecipitates are di scussed. (C) 1999 Elsevier Science B.V. All rights reserved.