Infrared Studies of Some Perovskite Fluorides. II. Multiphonon Spectra

Abstract
The transmission spectra of thin single‐crystal samples of KMgF3, KMnF3, KCoF3, KNiF3, KZnF3, and K (Mg0.5:Ni0.5) F3 have been investigated from 2.5–400 μ (4000−25 cm−1) at 300° and 85°K. A large number of bands have been observed in each material and these have been interpreted in terms of multiphonon processes at critical points in the lattice dispersion curves. The average energies of the phonon branches at the edge of the Brillouin zone have been deduced from the observed infrared spectra.