Ab initio study of structure and electrical conductivity of warm dense oxygen

Abstract

Using quantum molecular dynamics simulations, the equation of state and electrical conductivity of warm dense oxygen is calculated in the density and temperature ranges of 2.0–4.3 g/cm3 and 103–105 K, respectively. The simulations show that the dissociation of oxygen molecules at about 2000 K and 2.6 g/cm3 reaches 89%, and complex clusters form with increasing temperature and density. The dissociation of oxygen molecules significantly affects the electrical conductivity. The electrical conductivity of warm dense oxygen is greater than 105 S/m at pressures above 20 GPa and the oxygen is metallic, and then the electrical conductivity weakly dependent on pressure, up to 200 GPa. The density of states of liquid oxygen indicates conduction-state electron behavior in the warm dense matter regime.