碳离子碰撞单壁碳纳米管的动力学

采用分子动力学方法研究了碳离子碰撞碳纳米管中顶位、键中心和六元环中心的动力学过程。通过分析低、中、高3种入射能分别对碰撞过程的影响,探索了典型缺陷形成的微观演化过程。研究结果表明,碰撞碳纳米管中不同空间位置,其碰撞结果差异较大,其中顶位碰撞阈能最低,约为20 eV;碰撞六元环中心时碳管会发生严重变形,损伤最为严重。通过分析入射离子动能,碳纳米管热动能、质心动能以及势能随时间的演化规律,阐述了碰撞过程中的能量转移机制。

Collision Dynamics of a Carbon Ion Impinging a Single-Walled Carbon Nanotube

The collision dynamics of a carbon ion impinging the carbon atomic site, the center of a C-C bond and the hollow site at the center of the hexagonal ring of a single-walled carbon nanotube has been studied by molecular dynamics simulations. The microscopic evolution processes of the defect formation are explored by analyzing the collisions initiated with low, medium and high incident energy, respectively. Considerable difference is observed among the collisions at different impact sites in view of the incident threshold energy and the defect formation. For the collision at the carbon atomic site, the incident threshold energy is 20 eV, which is the lowest energy of defect formation. For the hollow site, the carbon nanotube is seriously deformed after collision. An energy conversion mechanism is proposed, based on the analysis of the time evolutions of energies. The kinetic energy of the incident ion is consumed in the form of the thermal kinetic energy, center-of-mass kinetic energy and potential energy of the carbon nanotube, which explains the energy transfer between the incident carbon ion and the nanotube.