Molecular dynamics simulation of the laser disintegration of aerosol particles.
Molecular dynamics simulation of the laser disintegration of aerosol particles.
复制标题
气溶胶颗粒激光分解的分子动力学模拟。
作者：
T. A. Schoolcraft;G. S. Constable;L. Zhigilei;B. Garrison
利用分子动力学模拟技术研究了短脉冲激光辐照下亚微米粒子的碎裂机理。在不同的激光能量密度进行模拟的颗粒具有均匀的成分和透明的夹杂物的颗粒。空间不均匀沉积的激光能量被发现发挥了重要作用，在定义的字符和程度的解体。导致粒子解体的过程包括粒子被照射面的过热和爆炸性分解、大粒子背面的溅射以及激光诱导压力松弛引起的透明夹杂物的破坏。所观察到的机制有关的衰变产物的性质和气溶胶飞行时间质谱的模拟结果的影响进行了讨论。多个激光脉冲的应用预计是有利的高效质谱采样的气溶胶与激光穿透深度比大的尺寸。
The mechanisms of disintegration of submicrometer particles irradiated by short laser pulses are studied by a molecular dynamics simulation technique. Simulations at different laser fluences are performed for particles with homogeneous composition and particles with transparent inclusions. Spatially nonuniform deposition of laser energy is found to play a major role in defining the character and the extent of disintegration. The processes that contribute to the disintegration include overheating and explosive decomposition of the illuminated side of the particle, spallation of the backside of large particles, and disruption of the transparent inclusion caused by the relaxation of the laser-induced pressure. The observed mechanisms are related to the nature of the disintegration products and implications of the simulation results for aerosol time-of-flight mass spectrometry are discussed. Application of multiple laser pulses is predicted to be advantageous for efficient mass spectrometry sampling of aerosols with a large size to laser penetration depth ratio.