Infrared Studies of Some Perovskite Fluorides. I. Fundamental Lattice Vibrations

摘要: The reflectance spectra of the cubic fluoride perovskites KMgF3, KMnF3, KCoF3, KNiF3, RbMnF3, and mixed crystals K (Mg0.8:Ni0.2) F3 (Mg0.5:Ni0.5) have been measured from 4000−40 cm−1 at 300° 85°K. all both temperatures fitted by means a classical dispersion analysis to yield frequencies, oscillator strengths, damping constants three ir active lattice vibrations. An assignment normal mode frequencies particular vibrations has made. high‐ low‐frequency dielectric these materials determined measurements. isotropic polarizabilities Mg2+, Mn2+, Co2+, Ni2+, Rb+ calculated. transverse effective charge 300°K obtained in order determine strength second‐order dipole moments due deformation during