Influence of Silicon on the Detonation Performance of Energetic Materials from First-Principles Molecular Dynamics Simulations

The development of new generation energetic materials (EMs) with improved detonation performance is of considerable importance for applications in civilian and military fields, but there is no clear understanding about how the specific atom type and molecular structure control detonating properties. To gain an atomistic-level understanding of the influence of Si element on the detonation properties of EMs, we carried out the RxMD(cQM) procedure, combining ReaxFF reactive molecular dynamics with quantum mechanics molecular dynamics, to predict the thermodynamics parameters of the Chapman-Jouguet (CJ) state as measurements of detonation performance. We find that the detonation temperature for tetrakis(nitratomethyl)silane (Si-PETN) is higher than that for pentaerythritol tetranitrate (PETN) because of high energy release while forming Si products. However, lower detonation pressure and detonation velocity for the Si-PETN system than those for PETN system were found because Si atoms attract nearby oxygen atoms from other molecules or fragments resulting in cluster products and leading to less gas product formation. Our results indicate that silicon-based energetic materials remain active in oxygen deficient conditions. This study uncovers how the specific atoms influence the detonation properties of EMs from the atomic perspective, providing useful information for designing EMs with improved properties.