Correlation between 151Eu Mössbauer isomer shift and Judd-Ofelt Omega 6 parameters of Nd3+ ions in phosphate and silicate laser glasses.

151 Eu Mossbauer effect measurements were carried out for various silicate and phosphate laser glases doped with Eu 3+ ions instead of Nd 3+ , for which Judd-Ofelt Ω t parameters are known. The isomer shift (IS) for the silicate glasses decreased with an increase in the electronegativity of the network-modyfying alkali and alkaline-earth metal ions, indicating a decreased 6s electron density of the rare-earth R 3+ ions, i.e., covalency of the R-O chemical bond. On the other hand, in phosphate glasses the IS increased with increased electronegatively