给体受体共轭型希夫碱的分子第一超极化率的理论研究

A Theoretical Investigation of Molecular First-Order Hyperpolarizability of Donor-Acceptor Conjugated Schiff Bases

采用HF/6-31G(d)//TDHF/6-31G(d)方法研究了给体受体共轭型希夫碱的几何结构和分子的第一超极化率,并与可利用的实验结果进行了比较.研究表明,这类希夫碱具有非平面的结构.另一方面,吸电子基和供电子基的种类,分子的共轭程度,基态与激发态之间的分子内电荷转移及HOMO-LUMO能隙对希夫碱分子的第一超极化率有明显的影响.

The geometrical structures and molecular first-order hyperpolarizabilities of donor-acceptor conjugated Schiff bases are investigated with HF/6-31G（d）//TDHF/6-31G（d） method and compared with available experimental results. Results indicate that on the one hand, these Schiff bases have non-planar structures, and that on the other hand, the type of donor-acceptor substituents, degree of molecular conjugation, degree of intramolecular charge transfer between ground and excited states and HOMO-LUMO energy gap have significant effects on molecular first-order hyperpolarizability.