Mössbauer-Effect Study of Europium in Glass

M\"ossbauer spectra have been obtained for ¹⁵¹Eu in some silicate and phosphate glasses. In the silicate glasses Eu³⁺ behaves very much as it does in Eu₂{O}₃$. The isomer shift relative to ${Eu}₂O₃ is {~}0.1 mm/sec. Some broadening of the line can be attributed to unresolved quadrupole splitting and to disorder in the glass structure. The recoilless fraction is 0.33. Measurements made at elevated temperatures indicate a complicated dependence of isomer shift on temperature cycling. In europium phosphate glass the isomer shift is {~}-0.3 mm/sec, and the linewidth is approximately the same as for the silicate glasses.