CL-20/HMX无规作用及共晶作用的理论计算

为了对比六硝基六氮杂异戊兹烷(CL-20)/环四亚甲基四硝铵(HMX)炸药分子间的无规作用及共晶作用,基于密度泛函理论(DFT),在B3LYP方法上使用6-311++G(d,p)基组优化得到了4种CL-20/HMX无规构型(Ⅰ、Ⅱ、Ⅲ和Ⅳ),对4种无规构型的几何结构、静电势、能量及电子密度拓扑进行了分析;利用分子动力学方法计算了共晶结构中H原子和O原子的径向分布函数;计算了不同摩尔比CL-20/HMX共晶的密度及爆速。结果表明,4种CL-20/HMX的无规构型存在氢键相互作用,氢键键长在0.274 2~0.296 4nm之间;4种无规构型的稳定性排序为:ⅣⅢⅡⅠ,构型的稳定性主要取决于氢键的数量和键长;4种无规构型在键临界点BCP处的电子密度ρ(r)大小排序为:ⅣⅢⅡⅠ,CL-20和HMX分子之间不仅存在H…O以及H…N形式的氢键相互作用,还存在N…O和C…O形式的范德华作用;共晶结构中CL-20与HMX的相互作用主要有氢键和强范德华力,氢键键长为0.22nm;CL-20/HMX共晶(摩尔比2∶1)的理论密度为2.003g/cm~3,理论爆速为9 608m/s。

Theoretical Calculation of the Random Interaction and Co-crystal Interaction of CL-20/HMX

To compare the random interaction and co-crystal interaction in hexanitrohexaazaisowurtzitane (CL-20)/ cyclotetramethylenete-tranitramine (HMX) explosive molecules, four kinds of random configurationsⅠ, Ⅱ, Ⅲ and Ⅳ were optimized by 6-311++G(d,p) basis set of B3LYP method based on density fuctional theory(DFT).The geometric structure, electrostatic potential, energy and electron density topology of four kinds of random configurations were analyzed respectively.The radial distribution function of H atom and O atom in the co-crystal structure was calculated by the molecular dynamics method.The density and detonation velocity of co-crystal with different CL-20/HMX molar ratios were calculated.The results show that hydrogen bonds exist in four kinds of CL-20/HMX random configurations, and the hydrogen bond length is between 0.2742 and 0.2964nm.The stability of four kinds of random configurations decreases in the order of Ⅳ>Ⅲ>Ⅱ>Ⅰ,which mainly depends on the number of hydrogen bonds and the bond length.The order of the electron density ρ(r) at the bond critical point (BCP) of four kinds of random configurations decreases in the order of Ⅳ>Ⅲ>Ⅱ>Ⅰ.Not only hydrogen bonds interactions in form of H…O and H…N but also Van der Waals forces in form of N…O and C…O exist between CL-20 and HMX molecules.The interactions between CL-20 and HMX in the co-crystal structure are mainly hydrogen bonds and strong Van der Waals forces, and the hydrogen bond length is 0.22nm.The theoretical density of CL-20/HMX co-crystal with molar ratio of 2∶1 is 2.003g/cm3, and the theoretical detonation velocity is 9608m/s.