OPTICAL PROPERTY AND LOCAL ENVIRONMENT OF NI2+ IN FLUORIDE GLASSES

Optical absorption and extended X-ray absorption fine structure (EXAFS ) spectra were measured on series of ZrF4-BaF2-LaF3, ZrF4-BaF2-MF-LaF3 (M; Li, Na, K, Rb, or Cs) and AlF3-BaF2-CaF2-YF3 glasses doped with N i2+. The optical absorption spectra show that Ni2+ ions in all the gla sses exist in octahedral coordination sites with six F- ions. The valu es of ligand field strength, 10Dq, were obtained from the optical abso rption spectra, and Ni-F interatomic distances, r(Ni-F), were determin ed by EXAFS analyses. The linear relationship between 10Dq and r(Ni-F) is found and interpreted by simple ligand field theory, The compositi onal dependence of the 10Dq and r(Ni-F) is discussed in terms of the b asicity of glasses, We discuss the optical property and the local envi ronment of Ni2+ in the fluoride glasses in comparison with those of ox ide glasses.