Optical Properties of KCl : Tl in the Extreme Ultraviolet Region

Abstract

The optical properties of KCl : Tl in the vacuum ultraviolet range were studied between room and liquid nitrogen temperatures. A new band was observed in both the absorption and excitation spectra on the long wave length tail of the exciton band, i.e. 7.19 ev at −180°C. From the measurements of the temperature dependence and the emission spectrum the band is supposed to be associated with a transition in Cl ions in the neighborhood of a Tl ion.
Excitation and emission spectra of fluorescence by the light in the fundamental band region, as well as thermal glow and optical stimulation curves of phosphorescence were also measured. The process of this luminescence is discussed.