Far-Infrared Reflectivity Spectra of KH₂PO₄ Crystal

Abstract

Far-infrared reflectivity spectra of KH 2 PO 4 crystal were measured from 16 to 400 cm -1 at the temperature range from 83 to 300°K, and complex dielectric constants were derived using a K.K. dispersion relation. The low frequency dispersion in c -polarization exhibits remarkable characteristics; (1) the high frequency tail drops far more steeply than ω -3 (in ε ''), and shows only a slight temperature dependence, (2) a significant structure is recognizable in the low frequency side slightly above the Curie point.