Predicting the detonation properties of energetic materials through phonons.

Context: Understanding the microscopic mechanisms underlying the detonation behavior of energetic materials is crucial for the development of safer and more efficient explosives. In this work, we employ first-principles calculations to optimize the molecular geometries of eight energetic compounds and analyze their phonon characteristics, including the number of molecular vibration modes in the doorway region (j) and the frequency gap (∆w). A new parameter, the phonon energy transfer rate, is defined and found to exhibit a strong linear correlation with detonation velocity (R = 0.95). The proposed model is further validated using an additional set of seven energetic materials, including one newly synthesized compound, showing excellent agreement with experimental results. These results suggest that the phonon energy transfer rate plays a critical role in the detonation process. Unlike conventional approaches that rely on macroscopic parameters, this study introduces a microscopic method for predicting detonation velocity based on phonon behavior.

Methods: All calculations are performed using the CASTEP code based on density functional theory (DFT), employing the Perdew-Burke-Ernzerhof (PBE) functional within the generalized gradient approximation (GGA) and Grimme's DFT-D dispersion correction. Norm-conserving pseudopotentials are used.