ELECTRICAL-CONDUCTIVITY CALCULATION IN AB-INITIO SIMULATIONS OF METALS - APPLICATION TO LIQUID-SODIUM

We describe a calculation of the electrical conductivity in ab initio simulations of liquid sodium, using the Kubo-Greenwood formula for the optical conductivity and the molecular-dynamics scheme;based on finit e-temperature density functional theory. The effect of different Brill ouin-zone samplings and that of the finite size of the system have bee n extensively studied at different temperatures. Close to the melting point, even with an adequate sampling of the Brillouin zone, our resul ts exhibit a large discrepancy between theory and experiment. This is much reduced at higher temperatures. The possible reasons for this beh avior are discussed.