Study of Raman spectra for γ-Al2O3 models by using first-principles method

The Raman spectra of spinel and nonspinel models for γ-Al2O3 were calculated by using a first principles method and an assignment on the basis of the proposed symmetry was established. The IR spectra were also calculated to validate the method. The results show that the Raman spectra are sensitive to the structural differences between the spinel and nonspinel models. The spinel model provides more medium peaks at the lower wave number range while the nonspinel model is much more flat. The Born effective charges, electron localization function, and dielectric tensors were also discussed briefly. These results provide valuable information for further insight into the structural properties of γ-Al2O3 in atomic scales.