有机分子二苯乙烯系列衍生物第一超极化率的理论研究

采用耦合-微扰Hartree-Fock方法(CPHF)，计算了二苯乙烯系列衍生物的静态第一超极化率.研究发现，具有离域的共轭体系和电子推拉对结构的分子，有利于发生分子内电荷转移，因而具有大的第一超极化率.进一步研究体系中取代基的位置，给体与受体的数量和得失电子的能力，分子的共面性和对称性对分子第一超极化率的影响，结果表明，有机分子拥有更多数量与更强得失电子能力的给体和受体，最高占据分子轨道(HOMO)和最低未占据分子轨道(LUMO)空间分布的不对称，具有较高的原子共面性和较低的分子中心对称性,都能显著增加关键词：二苯乙烯非线性光学第一超极化率空间效应

Theoretical study on the first hyperpolarizabilities of stilbene derivatives

Static first hyperpolarizabilities of a series of stilbene derivatives are calculated at the CPHF/6-311G(d) level. the molecules which possess the electron push-pull pair and delocalized conjugated bridge structure have larger first hyperpolarizabilities because of the intramolecular charge transfer. The influence of position of the substitution, strength and number of donors and acceptors, and their coplanarity and asymmetry is discussed. The results indicate that the molecules may have larger first hyperpolarizabilities when the molecules have stronger and more donors and acceptors, large asymmetry of HOMO and LUMO, better coplanarity and higher accentricity. This work attemps at finding out the relationship between the structure and the property, thus providing theoretical basis for designing nonlinear optical molecules.