Quenching and Temperature Dependence of Fluorescence in Rare-Earth Chelates

Abstract

Temperature dependence of the fluorescence quantum yield and decay time of several rare-earth chelates have been studied in an attempt to understand the quenching mechanisms in these compounds. It is observed that the quenching in either the ligand or the ion is reduced by lowering the amplitude of molecular vibrations. This indicates that a major part of the fluorescence quenching in rare-earth chelates occurs due to coupling of the electronic states to the environment through molecular vibrations. The results of the present measurement also indicate that the shielded 4f orbitals of the rare-earth atoms become more impervious to quenching when they are incorporated into a chelate. Importance of these results in connection with liquid laser research is discussed.