WCA soft attractive perturbation is used to build the free energy density function about the nitrogen adsorption.Thus the nitrogen adsorption behavior in interior of SWNT is calculated by DFT.

• 进而采用基本测量理论描述硬球分子相互作用，结合WCA微扰理论构建单壁碳纳米管内氮气吸附的自由能密度泛函，根据密度泛函的推导结果编程计算，分析并解析SWNT管内氮吸附行为。