In , we can find the Raman spectrum of anatase, "obtained by heating the glassy precursor to 450°C". The given frequencies of Raman bands are 147, 198, 320, 398, 448, 515, 640, and 796 cm -1 . Muzaffar Boda, 2018, explains that the Raman range 246-351 cm -1 corresponds to O-O covalent interactions. The modes at 144 and 197 cm -1 are due to Ti-Ti interaction in the unit cell. "Based on space group symmetry … group theoretical analysis shows Raman active bands at 144, 197, 392, 515 and 633 cm -1 which corresponds to Eg(1), Eg(2), B1g, A1g and Eg(3) modes of anatase phase, respectively. Eg bands arise mainly due to symmetric stretching vibration of O-Ti-O, B1g band is due to symmetric bending vibration of O-Ti-O and A1g mode is due to antisymmetric bending vibration of Ti-O-Ti in TiO2" . For modes in TiO2 nanotubes, see .