Force constant calculation from Raman and IR spectra in the three non-cubic phases of BaCeO3

Abstract

Raman spectroscopic data for BaCeO3 were modeled with the use of a small set of force constants in its three phases (Pnma, Imma and R3̄c) using experimental IR and Raman data. An IR reflectance spectrum of BaCeO3 in its Pnma phase is provided for the first time. Raman band symmetry assignments in the Pnma phase were re-examined and the assignments of Genet et al. were confirmed. The distribution of the Raman bands of the Pnma phase between the zone center and X point in Imma is provided and band assignments were extended to the Imma and R3̄c phases. Calculated values for both Raman- and IR-active modes are provided in the three phases. The variations in force constants throughout the phase transitions are briefly discussed. Copyright © 2001 John Wiley & Sons, Ltd.