Wu Xiaowei, Yu Qiyao
School of Life Sciences and Chemical Engineering, Jiangsu Second Normal University, Nanjing, 211200, People's Republic of China.
State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, People's Republic of China.
J Mol Model. 2024 Oct 30;30(11):388. doi: 10.1007/s00894-024-06190-x.
High-pressure chemistry has advantages in exploring novel energetic materials and is the key to the development of new high-energy materials. The complexity and danger of experimental processes require a deeper understanding by advanced simulation techniques. Therefore, a high-precision comparative DFT-D study was performed to investigate the effect of pressure on series of catenated nitrogen energetic crystals. The results show that there exist phase transitions for N, N, and N at 4 GPa, 3 GPa, and 2 GPa respectively, which are embodied in various properties of these crystals. Studies on band gap and DOS indicate pressure-induced improvement on the ability for electrons transition from occupied orbitals to empty ones. Hirshfeld surface analysis qualitatively suggests that hydrogen bonding interactions are becoming dominant inter-molecular interactions. The topological analysis quantitatively reveals that pressure is beneficial to enhancing the inter-molecular hydrogen bonding energy, thereby playing an important role in the stability of high-pressure phases. The discussions on mechanical properties imply that pressure can improve the rigidity of these energetic systems and enhance their mechanical properties. Our findings evidence the high-pressure phase transitions for catenated nitrogen energetic crystals, which lay the theoretical foundation for the development of novel energetic materials.
Series of catenated nitrogen energetic crystals N, N and N were obtained from experiments. Optimizations were performed by GGA/PBE functional and G06 dispersion correction within the framework of CASTEP code, and the cutoff energies of the plane waves were set to 700 eV. The particular moiety in the crystals was extracted by Multiwfn 3.6 and subsequent analysis was conducted by Gaussian 09W package.
高压化学在探索新型含能材料方面具有优势，是新型高能材料开发的关键。实验过程的复杂性和危险性需要先进的模拟技术进行更深入的理解。因此，开展了高精度的比较密度泛函理论-色散（DFT-D）研究，以探究压力对一系列氮连接型含能晶体的影响。结果表明，N、N和N分别在4 GPa、3 GPa和2 GPa时发生相变，这体现在这些晶体的各种性质中。对带隙和态密度的研究表明，压力促使电子从占据轨道跃迁到空轨道的能力得到提高。 Hirshfeld表面分析定性地表明，氢键相互作用正成为主要的分子间相互作用。拓扑分析定量地揭示了压力有利于增强分子间氢键能，从而在高压相的稳定性中发挥重要作用。对力学性能的讨论表明，压力可以提高这些含能体系的刚性并增强其力学性能。我们的研究结果证明了氮连接型含能晶体的高压相变，为新型含能材料的开发奠定了理论基础。
通过实验获得了一系列氮连接型含能晶体N、N和N。在CASTEP代码框架内，采用广义梯度近似（GGA）/Perdew-Burke-Ernzerhof（PBE）泛函和G06色散校正进行优化，平面波截止能量设置为700 eV。通过Multiwfn 3.6提取晶体中的特定部分，并由Gaussian 09W软件包进行后续分析。
