Excitation spectra of activator luminescence—the observation of a new D absorption band in KBr:In crystals

Abstract

We have investigated excitation spectra of the In⁺ ion luminescence directly excited by UV-light (6.1 to 6.4 eV) and creation spectra of the photostimulated luminescence, excited by F-band light after a preliminary monochromatic UV irradiation of KBr:In crystals with different In⁺ concentrations. Careful analysis of the excitation spectra allows us to detect a new D absorption band having a Gaussian shape with the following parameters: peak position at E₀ = 6.375 eV and half-width ΔE = 0.14 eV, effective absorption cross-section at the band peak [sgrave]_{D, max} = 6.9 10⁻¹⁶ cm². The oscillator strength f = 0.12 of the D band and quantum yield η = 0.012 ± 0.001 of In⁺ luminescence excited in the D band are also determined.