中文摘要：

用Gaussian09程序包的密度泛函理论DFT方法,在BP86/6-311＋＋g（d,p）水平上对O_2,TiO和TiO_2分子进行了优化.得到该系列分子的基态电子态分别为：O_2（x~3Σ_g）,Tio（x~3Σ_g）,TiO_2（X~1A_1）,TiO_2分子的稳定构型为C_（2v）构型.用Murrell-Sorbie势能函数对TiO和O_2分子的扫描势能点进行拟合,其扫描点都与四参数Murrell-Sorbie函数拟合曲线符合得很好,在此基础上推导出它们的光谱数据和力常数.用多体项展开理论导出TiO_2分子的全空间解析势能函数,在固定键角∠OTiO=110.5°的情况下,RTi-O=0.1652 nm处存在一个深度为15.09eV的势阱,表明在该处易形成稳定的TiO2分子.

英文摘要：

The molecular structures of ground state O_2,TiO and TiO_2 are calculated on the level of BP86/6-311＋＋g（d,p） using density function theory method in Gaussian09 programs.The results show that the electron states of the ground states of the molecules respectively are O_2（X~3Σg）,TiO（X~3Πg） and TiO_2（X~1 A_1）.The stable structure of TiO_2 molecule is of C_（2v） symmetry.Each potential energy curve is obtained via scanning the single point energies of TiO and O_2,which match well with those fitted with the fourparameter Murrell-Sorbie Function.according to which spectral data and force constants are deduced.The whole special analytical potential energy function of TiO_2 is derived from the many-body expansion theory.And there exists a potential trap of 15.09 eV depth at 0.1652 nm（R_（Ti-O）） when the OTiO angle is fixed at 110.5°,which suggests that a stable TiO_2 molecule could be formed easily.