Über den Einfluß von Zwischengitterionen auf die Absorption von Gitterlücken in KBr-Kristallen

Abstract

Detailed measurements have been made of the optical properties of α-centers (anion vacancies) in KBr: KH crystals irradiated monochromatically in the U band at 58°K. The absorption band α, normally at 6·14 eV is under these conditions shifted to shorter wavelengths. In terms ofFritz's model for the infrared absorption of U₁ centers, this shift can be interpreted as the influence of the nearby interstitial hydride ions on the a absorption. The nearest observed interstitial ion, stable to 103°K, shifts the α band to 6·31 eV; the next nearest one (stable to 150°K) to 6·19 eV; heating above 150°K leaves only the normal α absorption at 6·14 eV. Data are presented on the quantum efficiency for the recombination under uv irradiation and on the oscillator strengths for the different α centers.