摘要
Raman spectra of the nanophase titanium dioxide were examined at various annealing temperatures.The temperature dependences of the Raman modes at 702,612,422,230-250,and 152cm^(-1) are discussed.The 702 cm^(-1) A2g mode belongs to first-order phonon connected to a critical nature of the selection rules with respect to the grain size.Lower anatase-rutile transition temperature 700℃ is closely related to smaller grain size.The Eg mode at 422 cm^(-1) at room temperature shifts upward 24 cm^(-1) after successive annealing in air for one hour at 700℃,indicating the dependence of the lower mode frequency upon the larger oxygen deficiency.
