吡咯同系物C4H4XH(X=N,P,As,Sb)二阶超极化率的理论研究

用ab initio HF，MP2和B3LYP三种方法的输出结果，根据完全态求和公式自编程序计算了吡咯同系物的二阶超极化率．结果表明随着杂原子序数的增大，体系的二阶超极化率也随着增大．从对称性出发，利用二态模型讨论了体系光学非线性增大的原因．从杂原子基团与吡咯同系物二阶超极化率之间所成的线性关系，可以得出决定体系非线性光学性质的主要因素是杂原子．与呋喃同系物的光克尔效应相比，吡咯同系物是具有良好应用前景的非线性光学材料．

Theoretical Investigation of the Second Hyperpolarizability of Pyrrole Homologues C4H4XH (X=N, P, As, and Sb)

Using the results of the three different methods: ab initio HF, MP2 and DFT, the second hyper- polarizabilities of pyrrole homologues were calculated by self-compiling program according to sum-over-state formulae. The calculated results show that as heteroatom atomic number increased, the sec- ond hyperpolarizability increased subsequently. Starting from the symmetry, the reasons for the increasing nonlinearity were given by the two-state mold. From the linear relationship of the third nonlinear optical properties between the heteroatom group and the pyrrole homologues, the third nonlinear optical properties were largely determined by the heteroatom. Compared with the optical Kerr effect of the furan homologues, pyrrole homologues are good nonlinear optical materials in application prospect.