Lead Centres in Alkali Halides: NaCl, KCl and KBr

Abstract

The optical absorption spectra of x-irradiated lead doped NaCl and KCl crystals taken at room and liquid nitrogen temperatures show a new absorption band at 254 nm and an additional absorption in the 310 nm region. In the case of x-irradiated KBr:Pb crystal a new band at 278 nm is observed. These bands are attributed to Pb + centres from optical bleaching and other studies. The structure of the characteristic B band of Pb ++ ion observed for the first time in heavily doped KCl:Pb (=500 ppm) is also discussed.