Photoluminescence of KMgF3:Tl+

Luminescence of Tl+ impurity ions in single crystals of KMgF3 is measured under various optical excitations in the v.u.v. between 110 and 200 nm. The A' emission at 212 nm is observed under optical pumping in the A (203 nm), B (168 nm) and C (150 nm) absorption bands of Tl+ ions. The B' emission at 183 nm is accompanying the A' luminescence under excitation in the B and C absorptions. The decay kinetics of the A' emission, optically stimulated in the A absorption band, consists of two distinct exponential components (?f = 9 ns and ?s, = 14 ms, respectively, at low temperatures). Such results reveal a strict analogy with those known for Tl+ in alkali halides, in spite of different coordination spheres for the impurity ions. Peculiar features in KMgF3:Tl+ are the anomalous temperature dependence and the small Stokes shift of the A' emission, and a further luminescence at 243 nm which could be due to intrinsic deexcitation processes in the host material