Temperature-Dependent Infrared Absorption Due to an Li-Localized Mode in AgBr

The temperature-dependent infrared absorption spectra due to an Li-localized mode in AgBr have been measured. It is shown that the halfwidth increases linearly with temperature T for \(T{}90\) K, while it is constant for \(T{}20\) K. The temperature dependence is interpreted as resulting from decaying of the localized mode into two lattice phonons. The integrated absorption intensity of the fundamental band is observed to decrease as T 2 . The peak frequency slightly shifts to higher energy as the temperature increases in higher temperature region.