We have conducted ab initio calculations using density functional theory to investigate the structural, vibrational, and mechanical properties of 1,1-diamino-2-nitro-2-(1-amino-1H-tetrazol-5-yl) ethene, as a promising high-performance explosive. The effect of high pressures, up to 50 GPa, on the structure shows that there exists a possible pressure-induced structural transition around 21 GPa. The pressure-dependent intermolecular close contacts support the notion that molecular geometry is deformed and then rearranged to achieve a new equilibrium. Furthermore, we interpret significant molecular and intermolecular changes with assistance from calculated vibrational spectrum analysis. Apart from this, the calculated elastic constants demonstrate mechanical instability above 20 GPa, which aligns with the aforementioned structural change. Finally, we report bulk moduli, Young’s moduli, shear moduli, and Poisson’s ratio (ν), and the brittleness/ductility characteristics under high pressure are also analyzed.

中文翻译：

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1,1-二氨基-2-硝基-2-(1-氨基-1H-四唑-5-基)乙烯的压力诱导结构变化：一种不敏感的FOX-7类含能材料

我们使用密度泛函理论进行从头计算，以研究 1,1-二氨基-2-硝基-2-(1-氨基-1H-四唑-5-基) 乙烯的结构、振动和机械性能，作为有前途的高性能炸药。高达 50 GPa 的高压对结构的影响表明，在 21 GPa 左右可能存在压力引起的结构转变。压力依赖性分子间紧密接触支持分子几何形状发生变形然后重新排列以达到新平衡的观点。此外，我们在计算振动谱分析的帮助下解释了显着的分子和分子间变化。除此之外，计算出的弹性常数表明机械不稳定性高于 20 GPa，这与上述结构变化一致。最后，我们报告了体积模量、杨氏模量、剪切模量和泊松比 (ν)，并分析了高压下的脆性/延展性特征。