A Study of Intramolecular Energy Relaxation Processes of Rare Earth Complexes (RE(DBM)3， RE=Nd，Sm，Gd)

Intramolecular energy relaxation processes of rare earth complexes（RE（DBM）3，RE = Nd，Sm，Gd）have been studied by the photoacoustic amplitude and phase spectra. The amplitude intensities ofπ-π* transition of ligand in Sm（DBM）3，Gd（DBM）3 and Nd（DBM）3 increase gradually，but the phase data within the region of ligand absorption in the complexes of Gd，Sm and Nd decrease gradually，which shows intramolecular energy relaxation processes. For Gd（DBM）3 energy can’t transfer from the lowest triplet state of ligand to the 4f excited state of Gd3 + ，the triplet state relaxes to the ground state directly. For Sm（DBM）3 and Nd（DBM）3 energy can effectively transfer from the lowest triplet state of ligands to the 4f excited states of the central ions. The 4f excited states of Nd3 + almost relax nonradiatively to the ground state because the gap among the levels in Nd3 + is small. The energy of excited state in Sm3 + radiates partly because Sm3 + is a fluorescent ion. Combined these with the results of fluorescencespectra the models of intramolecular energy relaxation processes are established.