Optical absorption behavior of Tl+ DOPED Rb(Br1–x I x ) system

Abstract

The optical absorption behavior of Tl + doped Rb(Br 1-x I x ) mixed crystals (with x = 0.00, 0.05, and 0.10) grown under vacuum by slow cooling from the melt has been studied. Absorption spectra of the mixed crystals recorded at room temperature showed that the characteristic A-absorption band of Tl + ions in the Rb(Br 1-x I x ) system (0.1 mol. %) with x = 0.00 (i.e., RbBr:Tl + ) broadened with the iodine content towards the low energy side. Changes in the absorption spectra of the mixed crystals are due to creation of some complex centers involving Tl + , Br -, and I − ions with energy levels inside the band gap while forming the mixed crystal. The absorption spectra of gamma-irradiated mixed crystals showed the F-band, which shifted towards the low energy side due to the existence of iodine ions in the mixed crystals.