【摘要】 依据密度泛函(DFT)理论,利用PW 91方法,对聚酰亚胺二、三和四聚体进行模拟,研究其几何结构和电子结构.模拟结果表明,聚酰亚胺二、三和四聚体中间片断的键长、键角基本一致,采用低聚物中间片断结构,可以表征整个高分子聚合物结构,随着聚合度N的增加,总能量降低,能隙减小.更多还原

【Abstract】 According to DFT theory,the electronic structures of polyimide(N=2,3,4) are simulated by using PW1 method.The geometry structure and electronic structure of polyimide molecules are studied.The results show that the middle structures of polyimide(N=2,3,4) are consistent.It is proved that using middle structure of low polymer to describe the structure of high polymer is feasible,and with N increasing,total energy descends and the energy gap diminishes.更多还原