Why are buckyonions round?
Why are buckyonions round?
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DOI：
10.1007/s002140050299
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发表时间：
1998-02-01
影响因子：
1.7
通讯作者：
Scuseria, GE
中科院分区：
文献类型：
--
作者：
Bates, KR;Scuseria, GE
在石墨的电子辐照过程中，形成含有数万至数十万个原子的多层圆形碳颗粒（洋葱）。然而，大型二十面体富勒烯的理论模型预测了具有数百个以上原子的分子的高度多面形状。这种形状上的差异可以用碳洋葱形成过程中存在的缺陷来解释。在这里，我们使用碳的半经验紧束缚方法来模拟五边形-七边形缺陷在大型二十面体富勒烯表面的结合。我们展示了一种简单的机制，该机制会导致激烈竞争的衍生结构以及分子形状从多面到圆形的整体变化。我们的结果为圆形巴金离子的实验观察与多面二十面体富勒烯的理论预测之间的明显差异提供了合理的解释。
Multi-layered round carbon particles (onions) containing tens to hundreds of thousands of atoms form during electron irradiation of graphite. However, theoretical models of large icosahedral fullerenes predict highly faceted shapes for molecules with more than a few hundred atoms. This discrepancy in shape may be explained by the presence of defects during the formation of carbon onions. Here, we use the semi-empirical tight-binding method for carbon to simulate the incorporation of pentagon-heptagon defects on to the surface of large icosahedral fullerenes. We show a simple mechanism that results in energetically competitive derivative structures and a global change in molecular shape from faceted to round. Our results provide a plausible explanation of the apparent discrepancy between experimental observations of round buckyonions and theoretical predictions of faceted icosahedral fullerenes.