Spectroscopic properties of uranyl ions in fluorophosphate glasses

The optical absorption and luminescence spectra of the uranyl-doped fluorop hosphate glasses 75NaPO(3)-24.5SrF(2)-0.5UO(2)F(2) and 60NaPO(3)-24.5SrF(2) -15LiF-0.5UO(2)F(2) are discussed. The absorption spectrum of the uranyl io n in glasses shows less fine structure than the spectra of uranyl complexes in solution. The glass samples exhibit a strong luminescence typical for t he uranyl ion, and the luminescence spectrum is well resolved. It was found that the force constant of the vibrations in the ground state is intermedi ate between that in fluoride and phosphate glasses. During the glass prepar ation, reduction of uranyl to tetravalent uranium is often observed.