Effects of metal impurities on the optical properties of polyethylene in the warm dense-matter regime

For the warm dense-matter regime, we have examined the effects on the equation of state, conductivity, and optical properties of the introduction of a metal impurity (Al) into a poorly conducting mixture (CH₂) by means of quantum molecular-dynamics simulations employing temperature-dependent density-functional theory for temperatures between 1 and 4 eV and densities from ambient solid to a few times compressed. The properties such as dc conductivity and Rosseland mean opacity exhibit significant departures from the pure CH₂ results only for metal concentrations above about 50%. The system is representative of a wide range of environments that include planetary interiors, inertial confinement fusion capsules, and laser-produced plasmas.