基于第一性原理研究聚对苯二甲酸乙二酯的电子结构和光学性质

Poly (Ethylene Terephthalate) Electronic Structural and Optical Propertie from First Principles Calculations

基于密度泛函理论的第一性原理方法来研究聚对苯二甲酸乙二酯(PET)分子的电子结构和光学特性,结果表明:PET分子的轨道贡献主要是由O原子的2p轨道和C原子的2p轨道组成,而由能带结构计算得到的能隙比实验值要偏小;对于最高占据轨道,电荷密度主要分布在苯环两侧;而对于最低未占据轨道,最高的电荷密度主要分布在苯环上。由吸收光谱的吸收边得出的能隙与计算能带结构得到的结果一致,并解释了介电函数峰的形成和其它光谱特性的联系。

The electronic structural and optical properties of Poly（ethylene terephthalate）（PET） are studied based on first principle method of density functional theory.It shows that molecules orbit contribution of PET are derived from carbon 2p orbital and oxygen 2p orbital,respectively.However,the band gap from the energy band structure is much smaller than that of the experimental value.For the highest occupied molecular orbital,the charge density is mainly distributed in the both sides of the benzene ring.However,for the lowest unoccupied molecular orbital,the charge density is mainly distributed on the benzene ring.The band gap calculated from the absorption edge of absorption spectra is in agreement with the result of the energy band structure.Furthermore,the relationship between the formation of dielectric function peaks and other spectral characteristics is interpreted.