Raman spectra of CdF2 and PbF2

Abstract

The first-order Raman spectra of CdF2 and PbF2 have been recorded at 300, 77, and 4.2 °K. The spectrum in each case is a single line, arising from the triply degenerate F2g lattice mode. The observed frequency of this mode is 315 cm−1 in CdF2 and 257 cm−1 in PbF2. The frequencies shift slightly and the lines narrow considerably when the crystals are cooled. The Raman frequencies are used, together with previously known infrared and elastic data, to calculate the parameters of the rigid ion and the dipole shell models for these crystals.