Multibubble sonoluminescence of europium(III) chloride in heavy water

A weak glow in the region of the Eu3+ photoluminescence spectrum was detected against the background of the continuum of the solvent emission during multibubble sonolysis of air- or argon-saturated EuCl3 solutions (0.1 mol L-1) in heavy water. No characteristic sonoluminescence of the europium ion in aqueous solutions was observed earlier. Possible reasons for the low yield of Eu3+ sonoluminescence compared with other lanthanide ions (Ln(3+)) are discussed and the influence of europium on the spectrum of the solvent continuum related, in particular, to quenching of the electron-excited sonolysis products H2O* (D2O*) and Eu3+* in electron transfer reactions.