论文标题
SP缺陷迁移的分子动力学研究奇数富勒烯:富勒烯的丰富异构体的合成中的可能作用
Molecular Dynamics Study of sp-Defect Migration in Odd Fullerene: Possible Role in Synthesis of Abundant Isomers of Fullerenes
论文作者
论文摘要
为了解释最近的实验,表明奇特富勒烯在形成丰富的富勒烯异构体中的作用是反应性分子动力学(MD)研究。 MD模拟在3000 K中发现了三种类型的债券重排反应,在奇数富勒烯中,在所有其他SP $^2 $原子中都包含额外的SP原子。第一种类型是类似于表面上adatom迁移的交换机制的chastic sp缺陷迁移。第二种类型的COR-RESPONDS是由SP原子辅助的SP $^2 $结构的环形配置变化,这可能导致退火七元的环或五元环的分离。第三种类型是形成短生成的单配位原子或另外两个SP原子。在MD模拟中也观察到了一对SP缺陷的歼灭。结果表明,从执行的密度功能理论理论理论计算中,SP缺陷迁移事件的频率在较低的温度下的频率足以将SP原子传递到富勒烯地层时间期间SP $^2 $结构的缺陷。 Based on these results, we propose to supplement the self-organization paradigm of fullerene formation by the following four-stage atomistic mechanism of formation of abundant isomers of fullerenes: 1) attachment of single carbon atoms, 2) sp-defect migration to sp$^2$-structure defects, 3) sp$^2$-defect annealing assisted by the sp atom and 4) subsequent annihilation of成对的SP缺陷。
To explain recent experiment showing the role of odd fullerenes in formation of abundant fullerene isomers a reactive molecular dynamics (MD) study has been performed. Three types of bond rearrangement reactions are found by MD simulations at 3000 K in odd fullerenes which contain an extra sp atom among all other sp$^2$ atoms. The first type is sto-chastic sp-defect migration analogous to exchange mechanism of adatom migration on a surface. The second type cor-responds to changes in the ring configuration of the sp$^2$-structure assisted by the sp atom which can lead to annealing of seven-membered rings or separation of five-membered rings. The third type is formation of short-living one-coordinated atoms or two additional sp atoms. Annihilation of a pair of sp defects has been also observed in the MD simulations. It is shown that the frequency of sp-defect migration at a lower temperature, as estimated from performed density functional theory calculations of the barriers of sp-defect migration events, is sufficient to deliver the sp atom to defects of sp$^2$ structure during the fullerene formation time. Based on these results, we propose to supplement the self-organization paradigm of fullerene formation by the following four-stage atomistic mechanism of formation of abundant isomers of fullerenes: 1) attachment of single carbon atoms, 2) sp-defect migration to sp$^2$-structure defects, 3) sp$^2$-defect annealing assisted by the sp atom and 4) subsequent annihilation of pairs of sp defects.