中文摘要：

用密度泛函方法和ZINDO方法，从理论上研究了一系列四羧酸二萘嵌苯的衍生物（PTCDs）．对其平衡几何、电子结构和单双光子吸收性质进行了详细的计算研究．结果表明，此系列衍生物的双光子吸收截面主要由其主体结构（二萘嵌苯）决定．ΔEH-L（HOMO与LUMO间的能隙）的减小，HOMO轨道能量的增大，分子主轴两端取代基给电子强度的增强，共轭长度的增大以及分子刚性的增强都有利于此系列化合物双光子吸收截面的增大．并设计了比文献报道的C分子有更大的双光子吸收截面的两个分子D1，D2．

英文摘要：

The geometrical structure, electronic structure, one-photon absorption （OPA） and two-photon absorption （TPA） properties of the perylene tetracarboxylic derivatives （PTCDs） were studied theoretically by using DFT and ZINDO methods. And the results indicated that TPA cross-section of PTCDS was mainly determined by the main body of the molecule （perylene）, and there are several efficient ways to increase TPA cross-section of PTCDs： （1） decreasing the ΔEH-L （energy gap between HOMO and LUMO）, （2） increasing the energy of HOMO, （3） increasing the strength of donor groups on a lateral side, （4） extending the conjugated length, （5） increasing the rigidity of molecules. On the basis of that, two new molecules D1 and D2 have been designed, which have bigger TPA cross-section than molecule C referred in the reference.