Far-Infrared Properties of Cuprous Oxide

The transmission and reflectance of cuprous oxide has been measured from 6 to 250 μ and analyzed by classical dispersion theory. The two infrared-active vibrational frequencies are given by ${\nu }_1=613\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$ and ${\nu }_2=146.0\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$ with corresponding longitudinal-mode frequencies of 638 and 149 ${\mathrm{cm}}^{-1\mathrm{}}$. The maximum values of the extinction coefficient are calculated to be 2.7 and 4.0, respectively, for the two modes; both are higher than the literature values. The high-frequency and static dielectric constants are found to be ${\epsilon }_{\infty }=6.6\mathrm{}$ and ${\epsilon }_0=7.6\mathrm{}$, respectively.