THE FAR INFRARED SPECTRA OF SOME CUBIC PEROVSKITE FLUORIDES.
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Date
1965
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Publisher
Ohio State University
Abstract
The room temperature reflection spectra of a number of cubic perovskites have been measured at wavelengths from 2.5-1000 microns $(400-10 cm^{-1})$. Three strong reststrahlen peaks were observed in most cases and the results were analyzed by means of a Kramers-Kronig relationship to obtain the frequencies of the normal modes. A classical dispersion treatment having three infrared active vibrations with a small amount of interaction damping gave the best fit with the experimental data and provided vibrational frequencies, oscillator strengths and damping constants. The dispersion parameters for $KNiF_{3}$ are: ""[FIGURE]"" $$\begin{array}{ccccc}\epsilon_{\infty}=2.58&S_1=230&\omega_1=154&\gamma_1=13.5& \gamma_{12}=12.0\\ \epsilon_0=8.21&S_2=371& \omega_2=245&\gamma_2=22.5\\ &S_3=408&\omega_3=444&\gamma_3=22.0\end{array}$$ The work of the Spectroscopy Laboratory, MIT, was supported in part by the National Science Foundation, grant number GP-2111. The work from the Research Laboratory of Electronics, MIT, was supported in part by the Joint Services Electronics Program under contract DA36-039-AMC-03200(E).
Description
Author Institution: Spectroscopy Laboratory and Research Laboratory of Electronics, Massachusetts Institute of Technology; Bell Telephone Laboratories, Inc., Massachusetts Institute of Technology