中文摘要：

本文结合分子力学、半经验PM3和密度泛函（DFT）B3LYP方法对C80-C90的非分离五元环异构体和所有分离五元环异构体进行了理论研究。计算得到的B3LYP／6-31G’的最低能量结构与文献报道一致。而且，对于C80-C90，并不存在一个特别稳定的非分离五元环异构体，分离五元环规则仍适用于富勒烯C80-C90。

英文摘要：

All the isomers of fullerenes C80-C90 were generated and minimized using the second-generation reactive empirical bond order （REBO） potential to select 1000 low-energy candidate isomers. Then, these selected candidates were optimized with the semi-empiri- cal PM3 method to find the top 20 low-energy non-IPR （ isolated pentagon rule） isomers. Furthermore, these low-energy non-IPR isomers and all the IPR isomers of C80-C90 were optimized by density functional theory （DFT） method B3LYP with basis set 3-21G, and calculated energy at the B3LYP/6-31G ＊ level. It was found that the calculated lowest energy isomers of C80-C90 are in good agreement with the published results, and the IPR isomers are more stable than the non-IPR ones with large relative energies, which means that the IPR is still satisfied for C80-C90.