First-Principle Study on High-Pressure Behavior of Crystalline Polyazido-1,3,5-triazine

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• 作者：Fang Wang ; Hongchen Du ; Jianying Zhang ; Xuedong Gong
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：March 22, 2012
• 年：2012
• 卷：116
• 期：11
• 页码：6745-6753
• 全文大小：560K
• 年卷期：v.116,no.11(March 22, 2012)
• ISSN：1932-7455

文摘

A detailed study on the structural, electronic, and thermodynamic properties of the solid polyazide 4,4鈥?6,6鈥?tetra(azido)azo-1,3,5-triazine (TAAT) under the hydrostatic pressure of 0鈥?00 GPa was performed using the plane-wave density function theory method. The predicted crystal structure compares well with the experimental results at the ambient pressure. The results show that a pressure less than 40 GPa does not significantly change the crystal and molecular structures. When the higher pressure is applied, the molecular geometry, band structure, and density of states change regularly except at 48 and 90 GPa where the azide鈥搕etrazole transformation occurs. At 48 GPa, the tetrazole rings are almost coplanar with the triazine rings, whereas it has a big deviation at 90 GPa. The azide cyclization for polyazido-1,3,5-triazine has not been observed in the gas phase or polar solvents. Moreover, the band gap reduction is more pronounced in the low-pressure range than in the high-pressure region. The band gap decreases to nearly zero at 70 GPa. This means the electronic character of the organic crystal has metallic properties. An analysis of density of states shows that the electronic delocalization in TAAT increases generally under the influence of pressure. This shows that an applied pressure may increase the impact sensitivity.