中文摘要：

本文采用基于自旋极化的密度泛函理论系统研究了ConCm±（n=1-5;m=1,2）团簇的几何结构和电子结构特性.将ConCm±（n=1-5;m=1,2）团簇中的一个Co替换为C原子,个体的基态几何结构发生明显变化;在ConCm±（n=1-5）团簇的生长序列中,发现从n=3开始团簇中的两个C原子有彼此分离分布的趋势,本文分析,这是Co金属能够维持单壁碳纳米管（SCNTs）保持开口生长,成为非常有效的一种催化剂的重要原因.同时,将ConC±（n=2—5）团簇中添加一个Co原子后系统的总磁矩出现大幅下降的趋势,但仍保持奇偶交替的规律.通过比较中性及带电的ConC以及ConC2（n=1—5）团簇的碎裂能,本工作发现：由实验获取的SCNTs应均为带正电的体系,这一结论与已有的实验模型拟合得很好.

英文摘要：

The geometrical and electronic structures of ConCm±（n = 1—5,m = 1,2） clusters are investigated using spin-polarized DFT calculations.ConC±（n = 2—5） and ConC2±（n = 1—4） clusters of their ground-state structures different.From n = 3,two C atoms are located apart from each other,we think,it is an important reason for Co catalyze C in to single walled carbon nanotubes effectively. The total magnetic moment of ConC2±（n = 2—5） are lower than those of ConC±（n = 2—5） clusters,and they both alternated with odd and even numbers.By comparing the fragmentation energies of neutral and charged ConC and ConC2（n = 1—5） clusters,we conclude that the single walled carbon nanotubes obtained in experiment is electropositive.This conclusion is in good agreement with that from expersimental model