An alternative interpretation of the optical spectra for Fe3+-doped KTaO3 crystals

In this paper, the excitation spectrum and luminescence at 14 569, 17 225, 18 829 and 14 659 cm–1 for Fe3+ ion at the K+ site of KTaO3 crystals are assigned, respectively, to the 6A1(S)→4T1(G), 4T2(G), 4E1(G)[4A1(G)] and 4T1(G)→6A1(S) transitions rather than to the 6A1(S)→4T1(G), 2T2(I), 4T2(G) and 4T1(G)→6A1(S) transitions given in a previous paper [Bryknar et al., Radiat. Eff. Def. Solids 149(1999)51]. On the basis of this assignment, the reasonable optical spectrum parameters (in particular, the cubic field parameter Dq≈−640 cm−1) are obtained. The validity of this assignment is discussed.