ANALYSIS OF THE ABSORPTION-SPECTRA 4FN+1-]4FN5D-6S OF RARE-EARTH IONS IN THE CUBIC FIELD .2. EU2+ ION IN ALKALI-EARTH CHALCOGENIDES

For pt.I see ibid., vol.12, p.4081 (1979). The excitation spectra of MgS:Eu2+ phosphors were measured at 300 and 80K. Two distinct bands assigned to the 8 Gamma 4(t2g) and 8 Gamma 3(eg) bands appear for lower concentrations of Eu2+ ions and in addition, two bands assigned to the 8 Gamma 1(6s) and 6 Gamma 4(t2g) bands are observed for higher concentrations of Eu2+ ions. The shapes of the absorption spectra 4f7 to 4f65d-6s of an Eu 2+ ion in MgS are calculated by using the energy matrix for the 4fN5d-6s configurations and the atomic spectrum data for a free Eu2+ ion. Comparison between the observed and calculated results confirms the band assignment and leads to the determination of some energy parameters.