从头计算1，1 -二氨基-2，2-二硝基乙烯的结构、振动和准粒子能带结构
Structural, vibrational, and quasiparticle band structure of 1, 1 - diamino-2, 2 - dinitroethelene from ab-initio calculations
摘要：
采用第一性原理计算研究了压力对层状分子晶体FOX-7的结构和振动性质的影响。我们观察到显着的变化，在计算的结构性质与不同的修正处理范德华相互作用的密度泛函理论（DFT），与标准的DFT泛函相比。特别是，计算得到的基态晶格参数，体积和体积模量与Grimme的计划被发现符合得很好与实验。计算的振动频率表明FOX-7在压力下的分子内和分子间相互作用的依赖性。此外，我们还发现了一个显着的增加，在N-H。O氢键在压缩下的强度。这可以通过氮、氢和氧原子之间键长的变化以及在压力下计算的红外光谱来解释。最后，计算的带隙约为2.3 eV的GGA，并提高到5.1 eV的GW近似，这揭示了在高能量密度材料进行准粒子计算的重要性。
英文摘要：
The effect of pressure on the structural and vibrational properties of the layered molecular crystal 1,1-diamino-2,2-dinitroethelene (FOX-7) are explored by first principles calculations. We observe significant changes in the calculated structural properties with different corrections for treating van der Waals interactions to Density Functional Theory (DFT), as compared with standard DFT functionals. In particular, the calculated ground state lattice parameters, volume and bulk modulus obtained with Grimme's scheme are found to agree well with experiments. The calculated vibrational frequencies demonstrates the dependence of the intra and inter-molecular interactions in FOX-7 under pressure. In addition, we also found a significant increment in the N-H...O hydrogen bond strength under compression. This is explained by the change in bond lengths between nitrogen, hydrogen and oxygen atoms, as well as calculated IR spectra under pressure. Finally, the computed band gap is about 2.3 eV with GGA, and is enhanced to 5.1 eV with the GW approximation, which reveals the importance of performing quasiparticle calculations in high energy density materials.
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