ISSN:
1572-9559
Keywords:
alkali halide
;
defect modes
;
impurities in insulators
;
far-infrared spectroscopy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract The far-infrared reflectivity spectra of KI doped with 1% Cl− and 2% Na+ were measured using a dual cavity technique. In addition to the observation of all previously-observed resonant and gap modes, several features were discovered in and near the optic band. A new gap mode at 90 cm−1 in KI:Cl− was discovered. In both systems sharp, narrow reductions in reflectivity at 98, 108, 116, and 139 cm−1 were observed, as was a general reduction in reflectivity between 108 and 139 cm−1. The structure at 98 and 116 cm−1 is most-likely due to optical activity induced in normally inactive lattice modes by the high concentration of impurities. The features at 108 and 139 cm−1 and the reduction in reflectivity between them were shown by a simple model calculation to be due to an increase in damping of the TO phonon.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01009732
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