Electron-Ion Coupling in Shocked Energetic Materials

The magnitude and role of electronic excitations in shocked energetic materials are studied theoretically using quantum molecular dynamics simulations. Focusing on the detonating primary explosive HN 3 (hydrazoic acid), this work finds that the material transiently exhibits a high level of electronic excitation characterized by carrier densities in excess of 10 21 cm –3, or one electronic excitation for every eight molecules. Electronic excitations enhance the kinetics of chemical decomposition by ∼30%. The electronic heat capacity has a minor impact on the temperatures exhibited, on the order of 100 K. These simulations are performed using the self-consistent charge density functional tight-binding method (SCC-DFTB) combined with a new modification of a multiscale computational scheme for simulation of the coupling between electrons and ions in shocked matter.