以笼烯为接头的球棒式碳纳米管的电子结构

The Electronic Structure of the Carbon Nanotubes with the Cages as the Caps

按照Ｈａｍａｄａ构造一维至三维球棒式碳纳米管，构造了一些球棒式的笼烯接头的具有Ｃ３／Ｃ５旋转轴的单层碳纳米管．在Ｈｕｃｋｅｌ近似下，利用群论约化定理计算了它们的π电子结构，并对其稳定性进行了探讨．

Similar to the modified carbon nanotubes structure constructed by Hamada, we also constructed some simple carbon nanotubes models with the carbon element cages as the caps, which have C 5/C 3 symmetry. Under the Hckel approximation, the π electronic structures of the carbon nanotube models were calculated with the help of group reducible theorem. From these calculated results, some conclusions could be drawn: (1) For all carbon nanotube models, the average single electronic energy increases with increasing the numbers of the hexagonal layers. This implies that the longer carbon nanotubes might be potential molecules. Compared with the isolated C 55 and C 54 and the open carbon nanotubes, those models molecules are potential molecules. (2) For the molecules with subgraphs e, h and h, the number of bonding orbital is equal to that of antibonding orbital. So they are stable closed shell structure. (3) For the molecule with subgraphs a, b, c, d, f and g, the different values between the numbers of bonding and antibonding orbitals are 2,4,6,2,4 and 4, respectively. The molecules with subgraphs f also have two nonbonding orbitals. Therefore these molecules could form neutral or anion molecules. (4) The molecules with subgraphs i( k =3, 6 and 9), i( k =1, 4, 7 and 10) and j might form cation structure as their HOMOs are nonbonding orbital. (5) The molecules with subgraphs i( k =1, 4, 7 and 10) and j could form cation, and those molecules with subgraphs g and d could form anion, therefore it seems that the formers could interact with the latters to form two dimensional and three dimensional systems constructed by Hamada.