The frequencies of the optical phonons in NaCl${\mathrm{O}}_3$ have been located by measuring the infrared reflectivity and the Raman scattering spectra. By using the Lyddane-Sachs-Teller relationship, a value of 5.6 was found for the static dielectric constant. Dielectric transition strengths were determined from the transverselongitudinal frequency splitting and found to agree well with prior values obtained by analyses of infrared data. The reflection spectrum, the index of refraction, and the absorption coefficient have been determined throughout the range of the lattice resonances.

• Received 17 July 1969

DOI:https://doi.org/10.1103/PhysRev.188.1328