Dielectric properties of silver halide and potassium halide crystals.

The refractive indices of mixed AgCl(x)Br(1-x) crystals, with x ranging from 0 to 1, are measured at three wavelengths: 0.6328, 2.94, and 10.6 microm. A nonlinear dependence of the refractive index on composition is observed and explained on the basis of a simple Lorentz-Lorenz classical approximation. The theoretical dependence of the static dielectric constant on composition is also calculated. The same calculation is applied to KCl(x)Br(1-x) crystals, and, in both crystal systems, good agreement with experiment is obtained.