采用Lennard-Jones原子间势研究(C60)N分子团簇的结构演化行为

采用描述原子间相互作用的Lennard-Jones势来描述C₆₀分子间的相互作用,考虑了每个C₆₀分子的一定位置取向,并采用最速下降法计算了IH,fcc,hcp,DH及SC五种典型结构满壳层(C₆₀)_N团簇(N<2000)的能量.结果显示:当尺寸较小(N<20)时,IH结构最稳定;当尺寸处于中等(50<N<300)时,HCP结构最稳定;当尺寸较大(300<N 关键词： 60团簇')" href="#">C₆₀团簇 取向 最速下降法 结构演化

Study of structure evolution of (C60)N clusters usingLennard-Jones atom-atom potential

In this paper, we use the Lennard-Jones atom-atom potential to describe the interaction between C₆₀ molecules in (C₆₀)_N clusters. Considering the orientation of each C₆₀ molecule,we have calculated the energies of the closed-shell (C₆₀)_N(N<2000) clusters under five typical structurues, i.e., IH,fcc,hcp,DH and SC. Our results show that the IH structure is the most stable one in a small size (N<20),and the HCP structure is the lowest-energy one in a medium size (50<N<300),and the fcc structure is the most favorable one in a larger size(300<N<2000). With cluster sizes increasing,the average molecular energies of (C₆₀ )_N clusters decrease monotonically for the four typical structures of IH, fcc, hcp and DH,but the average molecular energy changes irregularly for the SC structure which undergoes structural reconstruction,implying that the SC (C₆₀)_N clusters are unstable in the size range investigated,and the lowest-energy structures of those (C₆₀)_N clusters are still far from their crystal forms.