Photooxidation of bivalent europium ions in hydrochloric acid aqueous solutions at room temperature

A dependence of photooxidation quantum yields of bivalent europium ions on HCl concentration is studied. The photooxidation effectiveness is found to grow with the increasing medium acidity during the irradiation both with 250 nm and 365 nm light. It is shown that triValent europium ion additions inhibit the photooxidation process in a special way. A conclusion is made that photooxidation of bivalent europium ions in acid aqueous solutions occurs by means of the electron transfer from the (Eu2+) ion excited state on a proton or another appropriate acceptor