Luminescence of Eu3+-activated thorium oxide

The luminescence of ThO2:Eu3+ has been studied in order to compare the luminescence of Eu3+ produced by photonic excitation ad by chemical excitation during a catalytic reaction. The photoluminescence varies with the Eu3+ concentration, the preparation process and the excitation modes (in the charge transfer band or in the 4f6 levels). This is explained by the existence of cubic and non-cubic sites for the Eu3+ ions, the populations of which vary with the concentration and the preparation process. The chemical excitation involves only non-cubic sites. (orig.)