Peculiarities of the Ni2+ ions in the crystal lattice of Bi12SiO20:Ni

Abstract Absorption measurements are taken over a wide spectral range which includes the visible, near and far IR region (500–22,272 cm −1 ). The exponential absorption edge parameters σ ( T ), σ 0 , W d and g are calculated for undoped and Ni doped Bi 12 SiO 20 at room temperature. The dopant nickel ion is double-charged and occupies the tetrahedral sites in the crystal lattice of doped sillenite. The energy level structure of the Ni 2+ ion in Bi 12 SiO 20 :Ni (BSO:Ni) is also presented. The crystal field parameter Dq and the Racah parameters B and C are calculated. It is established that the Jahn–Teller effect displays very strong influence in a distored tetrahedral Ni 2+ complex. The two-photon absorption of BSO:Ni is studied in far IR region.