物理化学学报 >> 2016, Vol. 32 >> Issue (8): 1977-1982.doi: 10.3866/PKU.WHXB201604293

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飞秒激光烧蚀含能材料的分子动力学模拟

杨镇1,刘海2,何远航1,*()   

  1. 1 北京理工大学,爆炸科学与技术国家重点实验室,北京100081
    2 中国空气动力研究与发展中心,超高速空气动力研究所,四川绵阳621000
  • 收稿日期:2016-04-19 发布日期:2016-07-29
  • 通讯作者: 何远航 E-mail:heyuanhang@bit.edu.cn

Molecular Dynamics Simulations of Femtosecond Laser Ablation of Energetic Materials

Zhen YANG1,Hai LIU2,Yuan-Hang HE1,*()   

  1. 1 State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, P. R. China
    2 Hypervelocity Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang 621000, Sichuan Province, P. R. China
  • Received:2016-04-19 Published:2016-07-29
  • Contact: Yuan-Hang HE E-mail:heyuanhang@bit.edu.cn

摘要:

为了得到飞秒激光侵蚀(FLA)1, 3二硝基甲苯(简称DNB,分子式:C6H4N2O4),六硝基六氮杂异伍兹烷(简称CL20,分子式:C6H6N12O12)和CL20/DNB共晶系统的物理和化学响应过程,本文采用ReaxFF/lg反应力场对其过程进行模拟。计算结果表明,CL20/DNB系统的温度和压力在飞秒激光加载过程中出现阶跃,激光加载过程后系统有一个冷却过程,然后系统的温度和压力逐渐升高达到最大值并维持平衡。研究发现,在此过程中CL20和CL20/DNB系统触发反应均为CL20分子中的N―NO2断裂。CL20系统的分解速率大于CL20/DNB共晶系统,这可能是因为共晶系统在反应初期具有大量的DNB分子以及分解产物中含有比较稳定的苯环减少了CL20及其产物之间的有效碰撞。

关键词: 飞秒激光, CL20/DNB共晶, ReaxFF/lg, 反应机理, 分子动力学

Abstract:

To understand the physical and chemical responses of energetic materials, such as 1, 3-dinitrobenzene (DNB, C6H4N2O4), hexanitrohexaazaisowurtzitane (CL20, C6H6N12O12), and CL20/DNB co-crystal, to femtosecond laser ablation (FLA), their molecular reaction dynamics have been investigated using the ReaxFF/ lg force field. The computational results indicate that the temperature and pressure of the CL20/DNB system jump during FLA. In particular, the temperature and pressure gradually reach their maxima following an initial cooling process. N―NO2 bond breaking of the CL20 molecule triggers the reactions for both the CL20 and CL20/ DNB systems. However, the CL20 system prevails the CL20/DNB co-crystal in the decomposition rate simply because coexistence of DNB molecules in the mixture and generated decomposition products containing benzene rings greatly reduce the effective collision probability between CL20 and the products.

Key words: Femtosecond laser, CL20/DNB co-crystal, ReaxFF/lg, Reaction mechanism, Molecular dynamics

MSC2000: 

  • O643