MOLECULAR-DYNAMICS STUDY OF DETONATION .1. A COMPARISON WITH HYDRODYNAMIC PREDICTIONS

We have compared the predictions of hydrodynamic theory for the proper ties of an unsupported detonation with the results of a molecular dyna mics simulation of such a phenomenon. The model of an energetic crysta l consists of heteronuclear diatomic molecules that require energy to break the molecular bonds (at ambient pressure); substantial energy is then released upon association of the products to form homonuclear di atomic molecules. The equation of state used in the hydrodynamic theor y is determined from two-dimensional molecular dynamics simulations of this model at various equilibrium conditions corresponding to volumes and temperatures appropriate to the detonation. The Chapman-Jouguet c onditions of detonation were thus determined. The properties of the de tonation were subsequently measured directly from two-dimensional mole cular dynamics simulations of the crystal model subjected to shock ini tiation. The agreement between the hydrodynamic predictions and the me asured properties is good. Deviations from exact agreement are attribu ted to slight differences in material composition in the detonation si mulation compared to that of the equation of state calculations. The c ritical property for sustained detonation using this model appears to be the attainment of the Chapman-Jouguet density.