The Photochemistry of Solutions of Eu(III) and Eu(II)

Abstract
Irradiation in the CT band of Eu3+ in aqueous solution, in the presence of scavengers for H atoms, gives rise to formation of Eu2+ and evolution of molecular hydrogen. The kinetics of these processes were studied as functions of the concentrations of Eu3+ and scavenger, of pH, and of light intensity. The results are interpreted by means of a complex scheme in which an excited Eu2+ donates an electron to a proton, the resulting H* initiating a series of dark reactions which lead to evolution of H2 and oxidation of the scavenger.