中文摘要：

用密度泛函方法，采用GGA／PW91方法对具有D6h对称性的C36及其衍生物Nb@C36进行结构优化和性能计算，探讨Nb@C36稳定构型；存在的可能性及稳定性；以及Nb掺杂对C36结构及性能的影响．结果表明，Nb位于C36主轴上偏离中心0．1nm时，Nb@C36能量最低，结构最稳定；Nb掺杂引起笼的局部畸变，但Nb@C36仍保持完整笼型结构．Nb@C36稳定性较C36有所提高，具有存在的可能性．Nb原子嵌入C36使其禁带宽度略有减小，导电性及化学反应活性有所提高；费米能级下降，但仍处于禁带之间，二者均属半导体性质的材料．C36结构及性能的变化与Nb所处的位置及Nb与C36笼之间的电子迁移有关．

英文摘要：

Geometries of C36（ D6h symmetry） and Nb@ C36 were optimized at the GGA/PW91 level using DFT approach. Structure, stability and existence of Nb @ C36 were discussed ; influence of the dope on structure and properties were studied. Results indicate that the energy of Nb @ C36 is the lowest and Nb @ C36 is the most stable when Mo is located on z-axis, off the center about 0.1 nm. Though the dope causes local deformation, Nb @ C36 keeps complete cage structure. Nb @ C36 are more stable than C36 and it has possibility of existence. Band gap is widened and conductivity and chemical reactivity is reduced. Both C36 and Nb @ C36 can be semi-conductor material. The change of structure and properties of C36 are related to location of Nb and electron transfer between dopant and cage, respectively.