低聚合物Pn(n=1-5)的化学活性和P在TiO2(100)表面吸附的密度泛函理论研究

采用密度泛函理论中的广义梯度近似（DFT/GGA）方法，在PW91/DNP水平上研究了低聚合物Pn(n=1-5)的稳定性和化学活性。结果表明：随着聚合度增加，Pn的稳定性降低，化学活性增强。采用密度泛函理论与周期性平板模型相结合的方法，研究了化合物P在TiO2(100)表面的吸附，通过吸附前后化合物P的Mulliken charge和前线轨道分析表明：当P吸附在TiO2(100)表面时，P向TiO2(100)表面转移0.692 e电荷，前线轨道能隙变窄。通过吸附前后TiO2(100)表面的能带和态密度分析表明：在TiO2(100)表面吸附了化合物P后，能带向低能区移动，且TiO2中价带和导带间的禁带消失。理论预测的结果与实验值吻合。

Density Functional Theory Study of Chemical Activity of the low polymer Pn(n=1-5) and P Adsorption on TiO2(100) Surface

The stability and chemical activity of the low polymer Pn(n=1-5) are investigated by density functional theory(DFT) at the GGA/PW91/DNP level. The computational results show that the stability gradually decreased and the chemical activity gradually strengthened with the increasing of the polymerization degree. Moreover, the density functional theory and periodic slab model are used to investigate the compound P adsorption on TiO2(100) surface. The Mulliken charge and frontier orbital of the TiO2(100)-P are also discussed. The results reveal that the charge of 0.692 e transfers from the P to the TiO2(100) surface and the energy gap becomes narrow during the adsorption has occurred. The energy band structure and density of states of the TiO2(100)-P are also discussed. The results reveal that the energy band shifts to the low energy and the band gap disappeares between the valence band and the conduction band during the adsorption has occurred. It is found that the above-mentioned theoretical calculations agree well with the experiment results.