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用自洽场晶体轨道法（SCFCNDO／2－CO）对聚噻吩的一些一取代物和二取代物的电子结构进行了研究，计算的取代基包括－CH3，－C2H5，－OCH3和－CN．计算结果表明，这些取代基基本没有影响聚噻吩主链的平面结构，除聚－3，4－二甲基噻吩的主链发生了40－°的扭转外，其它衍生物的主链仍处于同一平面.根据各取代高分子的电子特性我们得到结论：给电子基团和吸电子基团的取代都将使能隙（Eg）减小，价带宽和导带宽都较聚噻吩有所减小.给电子基团的取代将使高聚物的电离能和电子亲合势减小，更有利于p－型氧化掺杂．吸电子基因的取代将使电离能和电子亲合势都增大，更有利于n－型掺杂．文章对各种取代高聚物的晶体轨道进行了深入的分析和讨论．
The electronic structures of some monosubstituted and disubstituted polythiophenes were studied by using self-consistent field-crystal orbital method (SCFCNDO / 2-CO). The calculated substituents include -CH3, -C2H5, -OCH3 and -CN. The results show that these substituents have no effect on the planar structure of polythiophene main chain, except that the main chain of poly-3,4-dimethylthiophene is twisted by 40 °, the main chains of other derivatives are still in the same Plane.According to the electronic properties of the substituted polymers, we conclude that both the substitution of electron donating group and electron withdrawing group will decrease the energy gap (Eg), and the valence band and the conduction band will decrease compared with polythiophene. Substitution of the electron group will reduce the ionization energy and electron affinity of the polymer, which is more favorable for the p-type oxidation doping. Substitution of electron-withdrawing genes will increase both ionization energy and electron affinity, which is more favorable for n-type doping. The article has carried on the thorough analysis and the discussion to the various substituted polymer’s crystal track.