CL-20/HMX共晶THz光谱的理论研究

Theoretical Studies for THz Spectra of CL-20/HMX Cocrystal

通过共晶的方式来改善炸药的性能已成为含能材料领域的研究热点,共晶炸药的形成主要依赖异相分子间相互作用,而这些相互作用的能级跃迁正好位于太赫兹(THz)谱的检测范围。以六硝基六氮杂异伍兹烷(CL-20)/环四亚甲基四硝胺(HMX)共晶作为模型体系,采用分子动力学与量子力学相结合的方法,对共晶组分HMX和CL-20以及CL-20/HMX共晶的THz光谱进行了理论研究,对特征峰进行了振动模式的指认和分析,确认了不同分子间相互作用在THz谱上的响应。结果表明,与共晶单体CL-20和HMX相比,CL-20/HMX共晶出现了新的特征吸收峰,分别位于0.23,0.49,1.1,1.47,1.73,2.27 THz处。其中,1.1,1.47,1.73 THz处的吸收峰均由分子间C—H…O氢键引起,而1.73 THz处的吸收峰主要指配为异相分子间氢键。

The improvement of physicochemical properties of explosives by the way of cocrystallization has become a research hotspot in the field of energetic materials, the formation of cocrystal explosive is mostly driven by the intermolecular interactions, and their energy level transitions are located in the detection range of THz spectra. In this work, taking hexanitrohexaazaisowurtzi- tane（CL-20）/cyclotetramethylenete-tranitramine（HMX） cocrystal as the model system, the THz spectra of cocrystal components β-HMX, CL-20, and CL-20/HMX cocrystal were theoretically studied by combining the methods of molecular dynamics simulation and quantum mechanics. The assignment and analysis of vibration modes for characteristic peaks were carried out. The response of different intermolecular interactions in THz spectra was confirmed. Results show that compared with the cocrystal components CL-20 and HMX, the new characteristic absorption peaks of CL-20/HMX cocrystal located at 0.25,0.49, 1.1, 1.47, 1.73,2.27 THz and 3.7 THz respectively are found. Among them, the absorption peaks at 1.1, 1.47 THz and 1.73 THz are caused by intermolecular C-H...O hydrogen-bond , whereas the absorption peak at 1.73 THz is mainly assigned as the heterogeneous intermolecular hydro- gen bonds.