Infrared Dielectric Properties of Cadmium Fluoride and Lead Fluoride

Abstract

Infrared reflectivity measurements have been made on samples of cubic Cd${\mathrm{F}}_2$ and Pb${\mathrm{F}}_2$ between 10 and 150 μ at room temperature. The data have been analyzed by the use of reflectivity dispersion relations to obtain infrared dielectric properties of these substances as well as their optic-mode frequencies (transverse and longitudinal, TO and LO). For Cd${\mathrm{F}}_2$ we find ${\omega }_{\mathrm{TO}}=202\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$; ${\omega }_{\mathrm{LO}}=384\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$; ${\epsilon }_s=8.09\mathrm{}$. For Pb${\mathrm{F}}_2$, ${\omega }_{\mathrm{TO}}=102\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$; ${\omega }_{\mathrm{LO}}=337\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$; ${\epsilon }_s=27.4\mathrm{}$.