Ultrasonic attenuation measurements on crystals which display persistent nonphotochemical ir spectral hole burning

Zusammenfassung

Temperature-dependent ultrasound-absorption measurements have been used to identify an ReO4 --induced loss peak in alkali halide crystals. The measured shape is consistent with an activation process with barrier energies of 60 meV for RbBr, 50 meV for KI, and 30 meV for RbI. The temperature dependence of the hopping time is compatible with the disappearance of the persistent ir spectral features of ReO4 - as the temperature is increased to 10 K.