高等学校化学学报

高等学校化学学报 ›› 2005, Vol. 26 ›› Issue (6): 1126.

• 研究论文 • 上一篇    下一篇

C20三个异构体稳定性的从头计算研究

张国, 张明瑜, 孙家锺   

  1. 吉林大学理论化学研究所理论化学计算国家重点实验室, 长春130023
  • 收稿日期:2004-06-29 出版日期:2005-06-10 发布日期:2005-06-10
  • 通讯作者: 张明瑜(1942年出生),女,教授,博士生导师,主要从事量子化学计算研究.E-mail:2zhangmingyu@163.com E-mail:2zhangmingyu@163.com
  • 基金资助:

    国家自然科学基金(批准号:20273024,20473030)资助.

An Ab Initio Study on Stability of Three Isomers of C20

ZHANG Guo, ZHANG Ming-Yu, SUN Chia-Chong   

  1. State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
  • Received:2004-06-29 Online:2005-06-10 Published:2005-06-10

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摘要： 采用HF,B3LYP,MP2和QCISD等理论方法在6-31G和6-31G*基组水平上,对C20的3个主要异构体碟型(Bowl)、笼型(Cage)和环型(Ring)的结构进行理论研究,得出这3个异构体的相对稳定性的次序为:Ring>Bowl>Cage.计算结果显示,分子轨道具有离域特性,电子的这种离域特征有利于原子间更好的成键,可避免出现大的张力,这是Cage型异构体虽然违反“五元环隔离规则”(Isolatedpentagonrule)却能稳定存在的原因.

关键词: 从头计算, 密度泛函, 轨道多中心特性, 张力, 稳定性

Abstract: Three isomers of C20, bowl, cage, and ring, were investigated by using the HF, B3LYP, MP2, QCISD methods at 6-31G and 6-31G* level to obtain the optimized geometries and the order of their stability was as follows: Ring >Bowl >Cage. The calculated results show that the molecular orbital has multi-center characters and the electronic delocalization is favourable for bonding between atoms and can avoid the strong tension. This is the reason that the isomer of cage can exit stably though it breaks "isolated pentagon rule".

Key words: Ab initio, Density function, Orbital multi-center character, Tension, Stability

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