Quantum-molecular-dynamics simulations of liquid metals and highly degenerate plasmas

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Abstract
A numerical scheme based on time-dependent density-functional theory, for the simulation of systems of classical ions and quantum mechanical electrons, has been developed with the aim of modeling simple metals or highly degenerate plasmas from first principles. The electrons are represented by a set of three-dimensional wave functions obeying one-particle Schrödinger equations, subject to an effective potential. A pseudospectral method is used for the solution of the Schrödinger equations, coupled to a classical molecular-dynamics simulation for the ions. The scheme yields accurate predictions for the radial distribution functions and the ionic diffusion coefficients in liquid sodium, and is shown to correctly account for shielding due to the fully responsive electron background. Preliminary simulation results for bulk hydrogen under astrophysical conditions are also presented, including the successful modeling of chemical bonding in the isolated hydrogen molecule.