Abstract

Recombination luminescence in alkali halides is originated from the relaxed exciton in the form $\left({\text{X}}_2^{-}+\text{e}\right)$, where ${\text{X}}_2^{-}$ means halogen molecular ion. Similar situations have been recognized also in the cases of localized excitons in alkali halides containing heavier halogen impurities. Excitation into the absorption bands due to isolated halogen impurities gives rise to broad emission bands in the region of blue-green light (BG emission). They are attributed to the radiative decays from relaxed excited states with a configuration (XY⁻ + e) of two-center type, where XY⁻ means a heteronuclear diatomic molecule consisting of a host (X) and an impurity (Y) halogen ion.¹⁾

© 1984 Optical Society of America