碳纳米豆荚内C_(60)分子振荡行为的模拟  

Oscillatory behavior of carbon nanopeapods: A molecular dynamics simulation

作　　者：崔柳[1] 冯妍卉[1,2] 檀鹏[1] 张欣欣[1,2] 

机构地区：[1]北京科技大学机械工程学院,北京100083 [2]北京科技大学冶金工业节能减排北京市重点实验室,北京100083

出　　处：《科学通报》2015年第15期1414-1419,共6页Chinese Science Bulletin

基　　金：国家自然科学基金(51176011;51422601)资助

摘　　要：利用AIREBO势函数、L-J势函数结合分子动力学模拟方法,对碳纳米豆荚中C60分子的振荡行为进行了模拟.分别讨论了环境温度、碳管管壁层数及C60分子填充个数对碳纳米豆荚振荡性能的影响.研究表明,C60分子沿着碳管轴向做阻尼振荡运动.随着温度升高,振荡频率逐渐减小,振幅衰减速度加快.增加碳管管壁层数使C60分子与管壁间的范德瓦耳斯力增大而滑动摩擦力减小,因而有益于形成稳定振荡.由于C60分子间受力随距离变化以及分子间存在碰撞,增加C60分子填充个数并不能观察到稳定振荡.Since their discovery, carbon nanotubes （CNTs） have attracted a great deal of attention. Many investigations have indicated that CNTs possess various excellent properties including, for example, high Young＇s modulus, good field emission properties and superior thermal conductivity. CNTs are considered a promising candidate for nanoscale device applications. Because of their unique quasi-one-dimensional hollow structures, CNTs could act as hosts for guest materials. Various studies have demonstrated that the guest materials would strongly affect the properties of the host CNT. In this paper, the oscillatory behavior of carbon nanopeapods （CNPs）, which are CNTs containing encapsulated C60 molecules, was investigated by the molecular dynamics simulation. The structures of CNPs were built by HYPERCHEM. C-C bonding interactions were determined by the AIREBO potential, and the Lennard-Jones potential was used to express nonbonding interactions. Periodic and fixed boundary conditions were applied along the axial and radial directions of the CNT, respectively. A time step of 0.50 fs was imposed. The results of this simulation show that the C60 molecule in a CNP exhibits both translational and rotational motions. In particular, the axial translational motion is similar to the simple harmonic motion. The vibration frequency is in the order of dozens of gigahertz. The oscillation amplitude decreases with time because of the transformation of the van der Waals energy into thermal energy. Moreover, the amplitude decreases more rapidly at higher temperature because of the increased friction. Raising the temperature causes both the axial and radial velocities of the C60 molecule to increase, accordingly, the friction force is enhanced. Simultaneously, the C60 molecule exhibits elastic deformation under the effect of rotating centrifugal force, which further increases the friction. Additionally, the higher the temperature, the lower the oscillatory frequency will be. To improve the performance of this oscillator, the i

关 键 词：振荡 碳纳米管 C60分子 碳纳米豆荚 分子动力学 

分 类 号：TB383.1[一般工业技术—材料科学与工程] O613.71[理学—无机化学]