TiO_2电子结构的第一性原理计算

利用基于密度泛函理论的赝势方法对锐钛矿、金红石和萤石结构的TiO2进行模拟,研究了锐钛矿结构、金红石结构和萤石结构TiO2的基本性质参数,包括晶格常数、体弹模量B0和体弹模量对压强的一阶导数B0′。对模型进行结构优化后,应用第一性原理方法比较分析了三种晶型TiO2的电子结构,研究了其能带和态密度的分布情况,得出TiO2的价带主要是由O的2p态贡献的,导带主要是由Ti的3d态贡献的。得到三种晶型的禁带宽度,其中萤石结构的禁带宽度远小于金红石结构和锐钛矿结构,可以预计萤石TiO2光谱的吸收范围扩大,光催化性能会相应有所提高。

First-principles Calculations for Electronic Structure of TiO2 Compound

Anatase,rutile and fluorite TiO2 were simulated by ab initio calculations based on the density functional theory with the pseudopotential method.We obtained the lattic constant,the isothermal modulus B0 and its pressure derivative B′0.The structure was optimized under first-principles method.By analyzing band structure,density of states,valence band of TiO2 was mainly contributed by 2p density of oxygen and conductor band was mainly contributed by 3d density of titanium.The band gap was obtained and the results show that the band gap of fluorite TiO2 is smaller than that of rutile and anatase TiO2,the absorption range of fluorite TiO2 extends to the bigger region and the photocatalytic activity will be also improved.