Zhao Xiongce, Cummings Peter T
Nanomaterials Theory Institute, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
J Chem Phys. 2006 Apr 7;124(13):134705. doi: 10.1063/1.2185623.
We performed molecular dynamics simulation of double walled carbon nanotube (DWCNT) oscillators under constant energy and constant temperatures with various commensurations and nanotube lengths. We clarify and resolve questions and differences raised by previous simulation results of similar systems. At constant energy, sustained oscillation is available for a wide range of initial temperatures. But low initial temperature is advantageous for DWCNTs to sustain oscillation under constant energy. We observed sustained oscillation at constant energy for both commensurate and incommensurate DWCNTs. On the other hand, under constant temperatures, both high and low temperatures are disadvantageous to sustain DWCNT oscillations. At constant low temperature, neither commensurate nor incommensurate DWCNTs can maintain oscillation. At appropriate constant temperatures, the oscillatory behavior of incommensurate nanotubes is much more sustained than that of commensurate tubes. The oscillatory frequency of DWCNTs depends significantly on the length of tubes. The initial oscillatory frequency is inversely proportional to the DWCNT lengths. The oscillation frequency of DWCNTs is insensitive to the initial temperatures at constant energy, but slightly dependent on the temperature at constant temperatures.
我们在恒定能量和恒定温度条件下，对具有不同共格性和纳米管长度的双壁碳纳米管（DWCNT）振荡器进行了分子动力学模拟。我们阐明并解决了先前类似系统模拟结果所引发的问题和差异。在恒定能量下，对于广泛的初始温度范围都能实现持续振荡。但低初始温度有利于DWCNT在恒定能量下维持振荡。我们观察到共格和非共格DWCNT在恒定能量下均能实现持续振荡。另一方面，在恒定温度下，高温和低温都不利于维持DWCNT振荡。在恒定低温下，共格和非共格DWCNT都无法维持振荡。在适当的恒定温度下，非共格纳米管的振荡行为比共格纳米管更持久。DWCNT的振荡频率显著取决于纳米管的长度。初始振荡频率与DWCNT长度成反比。DWCNT的振荡频率在恒定能量下对初始温度不敏感，但在恒定温度下略微依赖于温度。
