基于中间插件延长法对聚对苯二甲酸乙二酯的电子结构及单光子吸收谱的研究

Study on the electronic structures and one- photon absorption spectra of poly( ethylene terephthalate) based on central insertion scheme

在杂化密度泛函理论B3LYP精度下,用本实验组参与发展的线性标度电子结构计算方法——中间插件延长法(central insertion scheme),计算聚对苯二甲酸乙二酯的电子结构,得到了它的量子尺寸效应,亦即能量间隙随尺寸的变化;并在此基础上计算了其单光子吸收谱。另外还在包含色散效应(dispersion effect)的密度泛函wB97XD精度下,计算其电子结构和单光子吸收谱。发现在wB97XD精度下,聚对苯二甲酸乙二酯的能量间隙明显增大,从而导致其单光子吸收谱发现明显的变化。另外两种精度下的体系的能量间隙随尺寸变化情况也不相同。这意味着色散效应对研究体系的电子结构和光学性质都有着明显的影响。

A central insertion scheme based on the ＂ divide - and - conquer＂ of Yang and Lee, which is proposed by Jiang et al. , is introduced in this thesis. It is used to calculate electronic structures of poly（ethylene terephthalate） , based on the hybrid density function theory B3LYP and density function theory wB97XD including dispersion effect level respectively. Furthermore, we obtain its one - photon absorption. By careful comparison, we found that the energy gap of the investigated system increase about - 3eV in the case of density function theory wB97XD ; Moreover, the number of the spectra feature is induced and it is located at the high energy area, which indicates that dispersion effect has an obvious influence on the electronic structures and optical property of poly （ ethylene terephthalate）.