气体分子与纳米粒子碰撞的分子动力学仿真分析

Molecular dynamics simulation of gas-nanoparticle collisions

当气体分子与纳米粒子碰撞的时候,纳米粒子传输理论预测到当纳米粒子的直径由小变大时,碰撞会由镜面反射转化为漫反射.文章利用分子动力学仿真研究了气体分子与纳米粒子碰撞的过程.在验证了这种转化存在同时,又探讨了碰撞转化的机理,即漫反射的起因.仿真结果揭示了漫反射的起因是由于纳米粒子对气体分子的吸附作用.这种吸附作用是由于纳米粒子对能量的容纳特性而产生的.

The gas kinetic theory of nanoparticle transport predicts that the collisions between gas molecules and a nanoparticle undergo a transition from specular to diffuse scattering when the particle diameter increases from molecular to micro - scale. We investigate the origin of diffuse scattering and verify the existence of the transition through molecular dynamics simulations. It is shown that diffuse scattering is the consequence of gas molecule absorption on the particle surface. Absorption results from the particle high ability of energy accommodation when the particle size is larger than a critical value.