Nanocrystalline TiO

2

powders(average grain-size of 22nm) were prepared by the sol-gel process.The structure of the powders at different annealing temperatures was studied by XRD.Using IR and UV-VIS spectroscopy

the optics-characteristics of the powders have been researched.The result showed with the transformation of crystal style

the optics-characteristics of the powders annealing at different temperatures have remarkable variation.Compared with raw crystal TiO

2

the IR absorbing sides of the nanocrystalline TiO

2

powders shift to both lower frequencies and higher frequencies

and with the grain-size becomes small

the UV-VIS absorbing sides shift to lower frequencies

showing the quantum size effect.