Ge Ni-Na, Wei Yong-Kai, Zhao Feng, Chen Xiang-Rong, Ji Guang-Fu
Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, College of Physical Science and Technology, Sichuan University, Chengdu, 610064, China.
J Mol Model. 2014 Jul;20(7):2350. doi: 10.1007/s00894-014-2350-1. Epub 2014 Jun 28.
The electronic structure and initial decomposition in high explosive HMX under conditions of shock loading are examined. The simulation is performed using quantum molecular dynamics in conjunction with multi-scale shock technique (MSST). A self-consistent charge density-functional tight-binding (SCC-DFTB) method is adapted. The results show that the N-N-C angle has a drastic change under shock wave compression along lattice vector b at shock velocity 11 km/s, which is the main reason that leads to an insulator-to-metal transition for the HMX system. The metallization pressure (about 130 GPa) of condensed-phase HMX is predicted firstly. We also detect the formation of several key products of condensed-phase HMX decomposition, such as NO2, NO, N2, N2O, H2O, CO, and CO2, and all of them have been observed in previous experimental studies. Moreover, the initial decomposition products include H2 due to the C-H bond breaking as a primary reaction pathway at extreme condition, which presents a new insight into the initial decomposition mechanism of HMX under shock loading at the atomistic level.
研究了高爆炸药HMX在冲击加载条件下的电子结构和初始分解。使用量子分子动力学结合多尺度冲击技术（MSST）进行模拟。采用了自洽电荷密度泛函紧束缚（SCC-DFTB）方法。结果表明，在11 km/s的冲击速度下，沿着晶格矢量b的冲击波压缩下，N-N-C角发生了剧烈变化，这是导致HMX系统发生绝缘体到金属转变的主要原因。首次预测了凝聚相HMX的金属化压力（约130 GPa）。我们还检测到了凝聚相HMX分解的几种关键产物的形成，如NO2、NO、N2、N2O、H2O、CO和CO2，并且所有这些产物在先前的实验研究中都已被观察到。此外，由于在极端条件下C-H键断裂作为主要反应途径，初始分解产物中包括H2，这为原子水平上冲击加载下HMX的初始分解机制提供了新的见解。
