Multiscale Modeling of Crystalline Energetic Materials.

The large discrepancy in length and time scales at which characteristic processes of energetic materials are of relevance pose a major challenge for current simulation techniques. We present a systematic study of crystalline energetic materials of different sensitivity and analyze their properties at different theoretical levels. Information like equilibrium structures, vibrational frequencies, conformational rearrangement and mechanical properties like stiffness and elastic properties can be calculated within the density functional theory (DFT) using different levels of approximations. Dynamical properties are obtained by computations using molecular dynamics at finite temperatures through the use of classical force fields. Effect of defects on structure is studied using classical molecular dynamics methods. Temperature induced reactions at elevated temperatures have been studied using ab initio molecular dynamics method for moderate size crystals of nitroethane. Furthermore, while presenting the state of the art in the study of modeling energetic materials, the current advances in the area as well as the limitations of each methodology are discussed.