TiO2基态和激发态的几何结构、激发能和偶极矩.pdf

物理化学学报( Wuli Huaxue Xuebao
Acta Phys.-Chin.Sin.2013,29(7),1441-1452
1441
Article]
doi:10.3866/PKU.WHXB201304221
www.whxb.pku.edu
TiO2基态和激发态的几何结构、激发能和偶极矩
韦美菊贾德强陈飞武
(北京科技大学化学与生物工程学院,北京100083
摘要:采用二阶微扰理论MP2、密度泛函B3LYP方法和含时密度泛函TD-B3LYP方法分别优化了TO2分子
的基态A1和六个激发态'B2、B2、1B1、2B1、A2和A2的几何结构A1、"B2B2、1B1和B1具有弯曲几何结构,A2和
A2具有线性对称结构.我们发现激发态B、B2、B1和B,键偶极矩的数值大小顺序和相应的键角大小顺序完全
致.另外,采用完全活化空间自治场( CASSCF) CASSCF(6,6) CASSCF(8,8)、多参考组态相互作用(MRC)和
含时密度泛函TD-B3LYP计算了TiO2分子各激发态的垂直激发能和绝热激发能.对B2、3B2和B1三个态
MRCI/CASSCF(6,6)计算的垂直激发能和绝热激发能与已有的实验值最接近.对其他三个激发态B,、A2和
A,计算的激发能和文献报道的激发能计算值基本一致.最后,还计算了TO2分子的基态和激发态的偶极矩
对1A1和B2态,偶极矩的计算值与已有的实验值相吻合.采用原子偶极矩校正的 Hirshfeld布居方法计算了TO
分子在A1B2、B2、1B4和B1态时各原子的电荷,发现从基态到激发态偶极矩的变化与电荷从氧原子向钛原子
的转移有关.整个计算中还考察了基函数cc-pVDZ、cc-pVTZ和 CC-PVQZ对计算结果的影响.
关键词:二氧化钛;几何结构;垂直激发能;绝热激发能;偶极矩
中图分类号:O641
Geometric Structures, Excitation Energies and Dipole Moments of the
Ground and Excited States of Tio
WEL Mei-ju JIA De-qiang CHEN Fei-wu
(School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, P R. China
Abstract: The geometries of the ground and excited states of titanium dioxide, A, B, B, B, 'B,A2,
and=A have been optimized using Moller-pesset second-order perturbation theory, density functional
theory B3LYP and time-dependent density functional theory TD-B3LYP methods. A, Bz,Bz, B1, B,, and
B, have bent structures, while A and A2 have symmetrical linear structures. The bond angles ofb, B,
an corelate directly th e magni ues of the corresponding bond dipole moments. Vertical
and
adiabatic excitation energies have been computed with complete active space self-consistent field
( CASSCF)CASSCF(6, 6), CASSCF(8, 8), multi-reference configuration interaction(MRC), and TD-B3LYP
For BB and B, the exci ation energies calculated with MRC/CASSCF(6, 6 )are much closer to the
experimental values than the results calculated using other methods. For excited statesb, A, and'a
excitation energies calculated with CASSCF(6, 6), CASSCF(8, 8), MRCI, and TD-B3LYP are almost
consistent with theoretical results available in the literature. Dipole moments of the ground and excited
states have been computed with B LYP and TD-B3LYP. The calculated dipole moments ofa and B2
agree well with experimental data. The atomic charges of Tio2 in ground and excited states have been
calculated wi e atomic i o moment coe ed His el poulation method. This calculation revealed
that changes of dipole moments from the ground state to the excited states are related to electron transfer
Received: January 21, 2013; Revised: April 22, 2013; Published on Web: April 22, 2013
Correspondingauthor.Email:chenfeiwu(@ust.edu.cn;Tel:+86-10-62332689
The project was supported by the National Natural Science Foundation of hina(21)and Fundamental Research Funds for the Central
Universities, China (FRF-TP-12-114A, FRF-BR-11-026B)
国家自然科学基金(2173020)和中央高校基本科研业务费专项资金FRF-TP-12-114A,FRF-BR-11026B)资助项目
C Editorial office ofacta Physico-chimica Sinica