摘要
为更好地研究小富勒烯分子的形成机理和存在方式以及更好地了解它们的各种物理化学性质,利用密度泛函理论,在B3LYP/6-31G*方法和基组水平下对分属D2h、C2h、C2、Ci和D3d对称群的C20富勒烯分子及异构体进行了结构优化、频率计算和自然键轨道分析,得到了它们的能量、能隙、振动光谱、电子结构特性。结果表明:C20分子具有明显的离域特征,这是它虽然违反五元环隔离规则却能够稳定存在的原因;所讨论的C20异构体的能量和能隙差别微小,属于等能体,其稳定性顺序为C2>D2h>D3d>Ci>C2h;各异构体的轨道杂化特征和电子转移特征也基本一致。研究发现红外光谱不适宜用来鉴别C20富勒烯分子的对称性,而喇曼光谱可能将D3d对称群的C20分子辨认出来。
The geometry structure, electric structure, the energy, the energy gaps and the spectra of C20 Fullerene and its isomers were studied by density functional theory at B3LYP/6-31G^＊ level for clarifying their various physical and chemical characters. The results show that the C20 molecular isomers have delocalized orbits which perhaps are the reasons why they are stable though they don＇t obey the IPR. The energies and the energy gaps of these isomers have little differences, which means they are similar to the Fullerene C20 molecule according to the decline of the symmetry, the sequence of the stablity are arranged C2〉D2h 〉D3d 〉 Ci 〉 C2h. The NBO computation suggests that the characters of the charge＇s transfer and the molecule orbit are almost resemble for the C20 molecular isomers. It is found that the infrared spectrum can＇t identify the symmetry of C20, and the ultraviolet spectrum can identify C20 with the D3h symmetry.
出处
《微纳电子技术》
CAS
2008年第8期448-452,共5页
Micronanoelectronic Technology
基金
国家重点基础研究发展规划(973计划)资助项目(2003CB716204)
教育部国际合作研究项目(20060360563)
南京大学固体微结构物理国家重点实验室项目(BM2003202)
关键词
富勒烯C20分子
异构体
几何结构
能级
振动光谱
Fullerene C20 molecule
isomers
geometry structure
energy levell vibration spectrum
