冲击波加载下TNT的初始反应路径及产物光谱特征研究  

Initial decomposition mechanism of condensed phase TNT under shock loadings and spectral character study of main reaction products

作　　者：牛振威 唐梅 葛妮娜 张修路[1] 马兆侠[4] NIU Zhen-Wei;TANG Mei;GE Ni-Na;ZHANG Xiu-Lu;MA Zhao-Xia(School of National Defense Science and Technology,Southwest University of Science and Technology,Mianyang 621010,China;Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory,Southwest University of Science and Technology,Mianyang 621010,China;State Key Laboratory of Environmental-friendly Energy Materials,Southwest University of Science and Technology,Mianyang 621010,China;Hypervelocity Impact Research Center,China Aerodynamics Research and Development Center,Mianyang 621000,China)

机构地区：[1]西南科技大学国防科技学院,绵阳621010 [2]西南科技大学核废物与环境安全国防重点学科实验室,绵阳621010 [3]西南科技大学环境友好能源材料国家重点实验室,绵阳621010 [4]中国空气动力研究与发展中心超高速碰撞研究中心,绵阳621000

出　　处：《原子与分子物理学报》2022年第2期83-97,共15页Journal of Atomic and Molecular Physics

基　　金：中国空气动力研究与发展中心超高速碰撞研究中心开放基金(20200202);国家自然科学基金(41704088)。

摘　　要：本文首先通过量子分子动力学方法结合多尺度冲击技术研究固相TNT晶体在冲击波加载下的初始分解反应路径及其产物组分变化.通过综合分析键长变化、电子布居和中间产物的存在寿命三个要素给出了不同冲击波速(3-15 km/s)下2类可能的初始分解路径:在低速冲击下(≤7 km/s),TNT发生部分分解和聚合,分解主要源于C-NO_(2)键的断裂,初始分解产物以NO_(2)为主;在高速冲击下(≥9 km/s)则发生完全分解,分解主要始于六元环的形成,即NO_(2)基团上的O与相邻CH_(3)基团上的H相结合,然后六元环被打破,生成了OH自由基,初始分解产物以CN、CO、C_(2)和OH为主.另外,根据模拟数据我们从理论上给出了TNT(ρ_(0)=1.7 g/cm^(3))冲击Hugoniot关系为U_(s)=3.377+1.363 u.随后以分子光谱理论为基础,采用含时密度泛函理论获取这些主要分解产物的紫外可见吸收谱、荧光发射谱及振动分辨的荧光发射谱.此项研究有助于我们深入认识TNT高温高压状态方程、分解反应机理及主要产物的光学特征,进而支撑超高速碰撞条件下的试验诊断.Molecular dynamics simulations in combination with multiscale shock technique were employed to study the initial chemical processes and the time evolutions of main reaction products of TNT under shock loadings.Two kinds of possible initial decomposition pathways were yielded through the analysis of bond length,electron population,and lifespan of middle products at the shock velocity of 3-15 km/s.The results indicated that the initial decomposition of shocked TNT is triggered by the C-NO_(2) bond dissociation,and the main decomposition product is NO_(2) under the low velocity impact(≤7 km/s).As the shock velocity rises(≥9 km/s),the decomposition process begins with the formation of a six-membered ring,namely the O atom of NO_(2)combines with the H atom of adjacent CH_(3),and the major products are CN,CO,C_(2)and OH.In addition,for TNT(ρ_(0)=1.7 g/cm^(3))the shock Hugoniot relation obtained is U_(s)=3.377+1.363 u.In the following,based on the theory of molecular spectra,the UV-Vis absorption spectra,fluorescent emission spectra,and vibrationally-resolved emission spectra were obtained via time-dependent density functional theory.This study provides extensive insights into the equation of state,the initial decomposition mechanism of shocked TNT and the optical characteristics of main decomposition products,which further support the diagnostic test at the hypervelocity impact process.

关 键 词：TNT 分解机理 产物组分 发射光谱 光谱精细结构 

分 类 号：O521[理学—高压高温物理]