Quantum molecular-dynamics study of the electrical and optical properties of shocked liquid nitrogen

Using quantum molecular-dynamics simulations, we show that the electrical and optical properties of shocked liquid nitrogen change drastically as the density increases along the principal and second-shock Hugoniots. Initially, a nonmetal molecular fluid at normal conditions, we find that nitrogen becomes a metal for pressures of 60 GPa and higher. This nonmetal-metal transition for fluid nitrogen can be directly associated to the continuous dissociation occurring along the Hugoniots, and is analogous to the high-pressure nonmetal-metal transition observed experimentally for two other homonuclear diatomic fluids, hydrogen and oxygen.