Revealing the Response of Structure and Decomposition Behaviors of 1, 1′-Azobis-1, 2, 3-Triazole to Pressure: A Theoretical Study

Abstract

1, 1′-azobis-1, 2, 3-triazole (C₄H₄N₈, N8) is a novel nitrogen-rich energetic material with excellent detonation performance, which has received widespread interest. Inspired by recent theories and experiments, the dependence of structural, vibrational, and electronic properties on high pressure up to 10 GPa was systematically investigated using periodic DFT calculations. It was found that the optimized structure belonged to the cis-N8 structure through comparing the theoretical IR with experimental IR spectra. The third-order Birch–Murnaghan equation of state for N8 was obtained up to 10 GPa, where the bulk modulus and its pressure derivative were 10.91 GPa and 7.689, respectively. More importantly, the pressure dependence of Laplacian bond order indicated that the five-membered ring opening was the first step in the decomposition process, and that high pressure could inhibit the decomposition process of N8 due to the reinforcement of non-covalent interactions. The present work could deepen the understanding of the energetic materials N8 under high pressure, and is of great significance to the blasting and detonation applications of N8.