SPECTROSCOPIC STUDIES OF SB3+ COLOR-CENTERS IN ALKALI-HALIDE SINGLE-CRYSTALS

The emission from KCl:Sb3+ and KI:Sb3+ excited in the A-absorption band was measured as a function of exciting photon energy and temperature. The A-band excitation produced two emission bands for KCl:Sb3+ and a single band for KI:Sb3+. The definitive assignment of these bands is presented in terms of the adiabatic potential energy surface (APES), in which the effect of the spin-orbit interaction (SO) on the Jahn-Teller (JT) interaction coupling to the E(g) mode is taken into account. The polarization spectrum and the angular dependence of polarization ratio of the A-band emission were also studied to determine the symmetry axes of the Sb3+-vacancies complex. The results indicate that the anisotropy is associated with the relaxed excited state (RES) of Sb3+. It is also found that the JT interaction coupling to the T2g mode and the vacancies, situated in the next-nearest-neighbor (nnn) and the nearest-neighbor (nn) positions to the Sb3+ ion, give rise to an additive perturbation.