SIMULTANEOUS TIME-RESOLVED FLUORESCENCE AND THERMAL LENS MEASUREMENTS - APPLICATION TO ENERGY-TRANSFER STUDIES IN EUROPIUM CHELATES

Simultaneous time-resolved fluorescence and thermal lens measurements are applied to the study of europium chelates in methanol, ethanol and acetonitrile. The intramolecular energy transfer from the ligand to the ion results in a strong increase in europium fluorescence. Simultaneously, a slow rising component of the order of microseconds is observed on the thermal lens curve. Both events are respectively related to radiative and non-radiative relaxation of the long-lived 5D0 state of europium ions.