Abstract
The infrared absorption by the localized vibrational modes of and centers in CsCl, CsBr, and CsI has been measured in the temperature range 20 to 300°K. Above 100°K, the temperature dependence of the half-widths of the local-mode absorption bands in CsBr and CsI follows a dependence, where (instead of , as is usually the case with the other alkali halides). Side-band structures are observed in CsCl and CsBr. These can be explained as arising from the coupling of the local-mode phonon with band phonons through anharmonic interactions. In the case of CsI, no such side-band structure is noted in the temperature range studied, except for a weak shoulder occurring very close to the main local-mode band.
- Received 16 September 1968
DOI:https://doi.org/10.1103/PhysRev.178.1492
©1969 American Physical Society