In order to find out the relationship between external pressures and properties of energetic materials, we used the density functional theory (DFT) method to investigate the structural, electronic, and absorption properties of crystalline 2,4,6-trinitrotoluene (TNT)/2,4,6-trinitrotoluene (TNB) under hydrostatic compression of 0–100 GPa. By analyzing the change of lattice constants (a, b, and c) of TNT/TNB under compression conditions, we found that variation tendency of the lattice constants was anisotropic. The b-axis is much stiffer than that along the a- and c-axes, which indicates that the TNT/TNB crystal is anisotropic within a certain pressure region. The pressure-induced structure transformation results in the new covalent bonds O11-C13, O12-C11, O8-C4, and O1-C12 at 60 GPa, and O4-C5 at 80 GPa, respectively. By analyzing the band structure and density of states of TNT/TNB in the pressure range over 40 GPa, the electronic structure of TNT/TNB changed to metallic system, which indicated it becomes more sensitivity under high pressures. The pressure-induced structure transformation of TNT/TNB also contributed to the relatively high optical activity of TNT/TNB at 70 GPa.

中文翻译：

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压力诱导的高能共晶TNT / TNB的结构行为：密度泛函理论研究。

为了找出外部压力与高能材料性能之间的关系，我们使用密度泛函理论（DFT）方法研究了结晶2,4,6-三硝基甲苯（TNT）/ 2的结构，电子和吸收性能，4,6-三硝基甲苯（TNB）在0–100 GPa的静水压力下。通过分析压缩条件下TNT / TNB的晶格常数（a，b和c）的变化，我们发现晶格常数的变化趋势是各向异性的。该b -轴是硬得多，比沿着一个-和ç-轴，表示TNT / TNB晶体在一定压力范围内是各向异性的。压力诱导的结构转变分别导致新的共价键O11-C13，O12-C11，O8-C4和O1-C12在60 GPa时和O4-C5在80 GPa时。通过分析在40 GPa以上压力范围内TNT / TNB的能带结构和状态密度，TNT / TNB的电子结构变为金属体系，这表明它在高压下变得更加敏感。TNT / TNB的压力诱导结构转变也有助于TNT / TNB在70 GPa时具有较高的光学活性。