β-HMX晶体结构及其性质的高水平计算研究

对β-HMX晶体进行DFT-B3LYP/6-31G计算研究，求得其能带结构和电子结构，探讨了结构-性能关系。从带隙约为5.7eV推知HMX晶体为绝缘体，计算所得晶格间相互作用能为149.29kJ.mol^-^1；计算的升华热(154.08kJ.mol^-^1)与实验值相符。晶体中相邻分子的硝基氧之间点电荷静电势要高，表明该处晶格易于断裂、并可能成为冲击引爆中心。从原子间距和原子间重叠布居分析，发现β-HMX分子之间存在微弱的氢键；环外以硝胺键较强，环内以N-C键较弱，预示该二部位易于引发分解和起爆。

High Level Calculations on Structure and Properties of Crystalline β-HMX

The banding and electronic structures and some properties of crystalline β-HMX are investigated at DFT-B3LYP/6-31G level. The crystalline β-HMX may be an insulator, which is judged from its band gaps about 5.7 eV. The heat of sublimation is predicted to be 154.08 kJ.mol^-^1 that is in good agreemnet with the experimental data. The point charge electrostatic potential is very high between the nitro groups of the neighboring molecules, which indicates that the crystal lattice in this positio may easily be broken adn becomes the explosion center when β-HMX is impacted. From the distance of atoms and the overlap population analysis, it is found that weak H-bonds exist between molecules of β-HMX and the bonds of N-NO2, N-C in β- HMX are weaker than others, which predicts that these two positions are susceptible to breaking down and causing explosion.