[Structure and Raman spectra of titanium oxides].

Under the first-principle density functional theory, structures of several titanium oxides (TiO, Ti2O3, Ti3O5, anatase and rutile) were optimized, and the obtained the structure parameter that coincides with the X-ray crystal diffraction result. The optimized structure parameters coincide well with those obtained by X-ray diffraction method. Molecular vibrational modes were also studied and assigned. Double Numeric including D-polarization function basis set was used with local density approximation, and the local exchange-correlation energy was described with Vosko-Wilk-Nusair and spin non-restricted function. The calculated vibrational wavenumbers were used to interpret observed experimental Raman spectra of those titanium oxides. By comparing the Raman spectra of those titanium oxides with the calculated results, the characteristic peaks of various titanium oxides could be assigned. So the types of titanium oxides could be diagnosed and recognized. This will help to investigate the correlation between the structure and property of materials.