Selective Excitation of Trivalent Thulium via Intramolecular Energy Transfer

The results of luminescence studies of thulium trisbenzoylacetonate and thulium trisdibenzoylmethide are reported. Selective excitation of the 1G4 level of Tm3+ via energy transfer has been achieved. Emission from the 3F4 level of the ion has been observed, and all the groups of lines appearing in the visible and near infrared spectral regions have been assigned. A quenching mechanism involving vibrational coupling of the ion with the ligand is discussed. Ligand field splitting is reported.