温度诱导CL-20相变的太赫兹光谱特性  

Terahertz spectral properties of temperature induced phase transition of CL-20

作　　者：何向阳 张祺[2] 王民昌[3] 刘泉澄 刘可[3] 李桂琳 康莹[3] 邓琥[1] 尚丽平[1] He Xiangyang;Zhang Qi;Wang Minchang;Liu Quancheng;Liu Ke;Li Guilin;Kang Ying;Deng Hu;Shang Liping(School of Information Engineering,Southwest University of Science and Technology,Mianyang 621010,China;Institute of Chemical Materials,Chinese Academy of Engineering Physics,Mianyang 621900,China;Xi'an Modern Chemistry Research Institute,Xi'an 710065,China)

机构地区：[1]西南科技大学信息工程学院,四川绵阳621010 [2]中国工程物理研究院化工材料研究所,四川绵阳621900 [3]西安近代化学研究所,陕西西安710065

出　　处：《红外与激光工程》2022年第12期279-285,共7页Infrared and Laser Engineering

基　　金：装备预先研究领域基金(80918010101)。

摘　　要：2,4,6,8,10,12-六硝基-2,4,6,8,10,12-六氮杂异伍兹烷(HNIW,CL-20)是一种具有笼形结构的高能化合物,在军事及民用领域具有广阔的应用前景。为了深入理解CL-20晶体相变物理机制,采用太赫兹时域光谱技术(THz-TDS)对23.0~179.8℃升温范围内的吸收光谱进行了研究。热作用下太赫兹光谱的显著变化表明136.8℃时CL-20开始发生不可逆相变,结合固态密度泛函理论(DFT)计算鉴别该转变为ε→γ相变。并且,对CL-20低频振动特性的分析表明,分子笼型骨架的振动模态在相变中发生了显著改变,分子间广泛的范德华相互作用是其重要来源。此外,骨架外硝基基团的旋转振动演变与分子的氢键作用密切相关。该研究为进一步理解CL-20在高温加载下发生相变乃至爆轰/爆燃过程中的复杂物理机制提供了参考,对新型CL-20基优质炸药的设计和合成具有重要意义。2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexazazoisowoodane(HNIW,CL-20)is a high-energy compound with a cage structure,which has broad application prospect in military and civil fields.In order to further understand the physical mechanism of the phase transition of CL-20 crystal,the absorption spectra in the temperature range of 23.0-179.8℃are studied by using the terahertz time-domain spectroscopy(THz-TDS).The significant change of terahertz spectrum under thermal action indicated that the irreversible phase transition of CL-20 begins at 136.8℃.Combined with the results of solid-state density functional theory(DFT),the transition is identified asε→γ-CL-20.Moreover,the analysis of the low-frequency vibration characteristics of CL-20 shows that the vibration modes of the molecular cage skeleton change significantly during the phase transition.The extensive van der Waals interactions between molecules are the source of this change.In addition,the evolution of the rotational vibration of the nitro group outside the framework is closely related to the molecular hydrogen bonding.This study provides a reference for further understanding the complex physical mechanism of CL-20phase transition and detonation/deflagration under temperature loading.It is of great significance for the design and synthesis of high-quality explosives based on CL-20.

关 键 词：太赫兹时域光谱技术 CL-20 密度泛函理论 相变 热加载 

分 类 号：O433.4[机械工程—光学工程]