Far ultra-violet absorption spectra of cerium(III) and europium(III) aqua ions

Abstract

The far ultraviolet absorption spectra of Ce and Eu is reported and discussed. The relatively broad and weak electron transfer bands were found to have the lowest wave-number in the most oxidizing central ion, Eu(III). A solution of 0.03 M Eu(III) perchlorate in 0.1 M HClO4 shows a maximum at 188 m mu , with the molar extinction coefficient epsilon = 235 and the half- width towards smaller wave-numbers delta (--) = 5.1 kK. Other lanthanide solutions, such as Ce(III), Pr(III), and Tb(III) perchlorates, exhibit relatively narrower bands caused by 4f→5d transitions. A sixth band of Ce(III) was found at 200 m μ with epsilon = 170 and delta (+) = 1.4 kK.