Analysis of the absorption spectra 4fN+1to 4fN5d-6s of rare-earth ions in the cubic field. II. Eu2+ion in alkali-earth chalcogenides

Abstract

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(t_2g) and ⁸ Gamma ₃(e_g) bands appear for lower concentrations of Eu²⁺ ions and in addition, two bands assigned to the ⁸ Gamma ₁(6s) and ⁶ Gamma ₄(t_2g) bands are observed for higher concentrations of Eu²⁺ ions. The shapes of the absorption spectra 4f⁷ to 4f⁶5d-6s of an Eu²⁺ ion in MgS are calculated by using the energy matrix for the 4f^N5d-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.