Computer simulations for shock-compressed liquid deuterium: Failure of density-functional theory and molecular dynamics

Abstract

We show that the disagreement of recent laser driven shock wave experiments for liquid deuterium with Hugoniots calculated with the generalized gradient approximation molecular dynamics (GGA-MD) method stems from the underestimate of the metalization density associated with density functional theory (DFT). This leads to an enhanced degree of thermally induced molecular dissociation with the result that computer simulations fail to achieve the compression observed experimentally. Scaling of the GGA-MD Hugoniot to hypothetical GW Hugoniot results, using the ratio of volumes at which the GW and DFT band gaps close, leads to a prediction in good agreement with experiment.