聚酰胺酸及其接枝衍生物的荧光光谱理论研究

Theoretical Studies on Fluorescence Spectra of Polyamic Acid and It's Grafted Derivatives

文章采用量子化学半经验方法PM3对聚酰胺酸(PAA)及经p-π共轭接枝上一系列不同侧链的衍生物(GPAA1-4)进行了理论计算,优化得到了它们的平衡几何构型,计算了它们的谐振动频率,均未出现虚频,证明优化得到的是稳定结构。在此基础上采用单激发态组态相互作用(CIS)方法计算了它们的荧光激发波长及强度,所得结果与实验值变化趋势基本吻合。作者发现PAA经p-π共轭接枝上侧链后,荧光强度明显加强,而且随着侧链烷基的加长,荧光强度也随之加强。这有助于指导设计和合成聚合物荧光材料。

A theoretical study on the polyamic acid （PAA） and its derivatives with different side chain （GPAA1-4） by semi-empirical PM3 is presented in this paper. After optimization, the authors get their balanceable geometric configurations. For all optimal geometric configurations, there is no imaginary frequency in vibrational analysis, which proves that the geometric configurations are stable. On this basis, the electronic spectra have been calculated by a single-excitation configuration interaction （CIS） method. Tie calculated results are consistent with experimental values on the whole. The authors found that the fluorescence intensity of polyamic acid （PAA） with p-π conjugation side chain is enhanced obviously, and the longer the alkyl side chain the more intense the fluorescence will be. This will help us to design and synthesize the polymer fluorescence material.