中文摘要：

对sol—gel法制备的不同稀土元素（Ce，Nd，Sm）掺杂的纳米Ti魄粒子进行研究。X射线衍射（XRD）和X射线光电子能谱（XPS）分析结果表明，稀土离子均以间隙的形式均匀分布在纳米Ti@晶格内。傅里叶变换红外光谱（FTIR）和太赫兹时域光谱（THz-TDs）显示，掺杂TiO2较纯TiO2具有更强的红外活性；在0．2～1．70THz波段，TiO2的折射率随着频率的增加而减小，并呈现反常色散现象；Ce掺杂引起新的特征吸收，分别为1．35和1．58THz，且造成太赫兹吸收谱的吸收边发生红移，Nd和Sm掺杂则造成吸收边蓝移。在0．2～1．7THz范围内，Sm掺杂引起的介电损耗角正切值（tanδe）最小，其平均值为0．05。

英文摘要：

Lanthanidc-doped nano-TiO2 samples with different Ti/Ln （Ln = Ce, Nd, and Sm） were synthesized by sol-gel method. The samples were characterized by X-ray diffraction（XRD）, Fourier transform infrared spectroseopy（FTIR）, X-ray photoelectron spectroscopy（XPS） and terahertz time-domain speetroscopy（THz-TDS）. The results indicate that Ce, Nd, and Sm ions were uniformly dispersed into the TiO2 ; and the infrared activities of lanthanide-deped nano-TiO2 were much stronger than Undoped nano-TiO2, the refractive index of anatase TiO2 declines with frequency increasing in the frequency range of 0. 2 1.70 THz at room temperature, and it exhibits anomalous dispersion. Unique characteristic absorption peaks at 1.35 and 1.58 THz were observed from Ce-doped nano-TiO2. Compared with undoped nano-TiO2, the absorption edges of Ce-doped nano-TiO2 were red-shifted remarkably and those of Nd and Sm ions doped nano-TiO2 were blue-shifted. Sm-doped nano-TiO2 has induced the least dielectric losses in the frequency range of 0. 2-1.7 THz, and the average value is 0. 05.