Vibronic excitation spectrum of alkali aluminometaphosphate glasses containing uranium

The absorption, excitation and emission spectra of metaphosphate glasses MPO₃.Al(PO₃)₃ (M = Li, Na, K) doped with 1 or 2 w.% of uranium oxide have been measured at room temperature. The spectra were compared with those of solid uranyl nitrate and its water solution. The excitation band of glasses peaking at about 420 nm shows a great deal of structure like that of the solution. The diffuse structure would be due to the electron vibronic transitions in the uranium centre of a molecular form (probably uranyl (UO₂)²⁺).