Zong He-Hou, Zhang Lei, Zhang Wei-Bin, Jiang Sheng-Li, Yu Yi, Chen Jun
Institute of Chemical Materials, China Academy of Engineering Physics (CAEP), Mianyang, 621900, China.
Software Center for High Performance Numerical Simulation, Institute of Applied Physics and Computational Mathematics, Beijing, 100088, People's Republic of China.
J Mol Model. 2017 Sep 10;23(10):275. doi: 10.1007/s00894-017-3446-1.
In this work, we report the structure, mechanical properties, and vibrational spectra of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), an energetic molecular crystal, with a first-principles method based on density functional theory (DFT) using the recentely developped HASEM package. The elastic constants, acoustic velocity, and parameters of equations of state were calculated, and the predicted ordering of stiffness constants is C (38.5 GPa) > C (24.0 GPa) > C (17.7 GPa). We also investigated the structure and equation of state of LLM-105 under hydrostatic pressure up to 100 GPa. The predicted structures are in good agreement with experimental results available from ambient pressure to 20 GPa. Under compressions, the LLM-105 crystal exhibits anisotropic compressibility, with a highly incompressible response along the a-axis and c-axis. It is worth noting that there is a sudden change in the lattice parameters and change rate of volume at ~30 GPa. Based on the intermolecular interaction analysis and vibrational spectra, a phase transition at the hydrostatic pressure of ~30 GPa is predicted.
在这项工作中，我们使用基于密度泛函理论（DFT）的第一性原理方法，借助最近开发的HASEM软件包，报告了高能分子晶体2,6 - 二氨基 - 3,5 - 二硝基吡嗪 - 1 - 氧化物（LLM - 105）的结构、力学性能和振动光谱。计算了弹性常数、声速和状态方程参数，预测的刚度常数顺序为C （38.5吉帕）> C （24.0吉帕）> C （17.7吉帕）。我们还研究了高达100吉帕静水压力下LLM - 105的结构和状态方程。预测的结构与从常压到20吉帕的现有实验结果吻合良好。在压缩过程中，LLM - 105晶体表现出各向异性压缩性，沿a轴和c轴具有高度不可压缩响应。值得注意的是，在约30吉帕时晶格参数和体积变化率存在突然变化。基于分子间相互作用分析和振动光谱，预测在约30吉帕静水压力下会发生相变。
