单个水分子与碳纳米管的离散-连续混合模型--水分子进入碳纳米管的条件及其相互作用力、速度和能量分布

Detailed Investigation Into a Single Water Molecule Entering Carbon Nanotubes

研究水分子进入碳纳米管(CNT)时的物理特性.采用连续模型连同Lennard-Jones势函数,得到单壁面碳纳米管(SWCNT)与单个水分子之间的van der Waals力.水分子选择3种方位进入纳米管,其中水分子质心位于纳米管轴线上.对不同的纳米管半径和水分子进入方位,广泛地研究了相互作用力、能量和速度的分布.用分子动力学(MD)模拟得到的结果,来验证上述得到的相互作用力和能量分布.导出水分子进入纳米管时的可吸入半径,并详细地给出了有利于水分子进入纳米管半径的界限.计算单个水分子进入纳米管的速度,为不同进入方位的水分子,给出最大的入口速度和最大的管内速度.

The behavior of a water molecule while entering carbon nanotubes（CNTs） was studied.The Lennard-Jones potential function together with the continuum approximation was used to obtain the van der Waals interaction between a single-walled carbon nanotube（SWCNT） and a single water molecule.Three orientations were chosen for water molecule as the centre of mass located on the axis of nanotube.Extensive studies on the variations of force,energy and velocity distributions were performed by varying the nanotube radius and the orientations of water molecule.The force and energy distributions were validated by those obtained from molecular dynamics（MD） simulations.The acceptance radius of nanotube for sucking the water molecule inside was derived also specified in which limit of radii,nanotube was favorable to absorb water molecule.The velocities of a single water molecule while entering nanotubes were calculated and maximum entrance and interior velocity for different orientations were assigned.