Raman spectra of barium halides in orthorhombic and hexagonal symmetry: An ab initio study

Vibrational properties of bulk crystalline barium halides BaCl2, BaBr2, and BaI2 are theoretically investigated for orthorhombic and hexagonal symmetry with ab initio methods in density functional theory. It is demonstrated that the used method is capable of predicting frequencies of vibrational modes, their symmetry types, and corresponding Raman intensities in reasonable agreement with experimental data for orthorhombic and hexagonal BaCl2 and BaBr2 nanocrystals embedded in fluorozirconate glasses. For orthorhombic BaCl2, a Raman-active phonon mode could be predicted theoretically that was not observed in measurements before.