Transport coecients of liquids from ®rst principles

The use of ®rst-principles molecular dynamics to calculate the viscosity of liquid metals using the Green±Kubo relations is described. The ®rst-principles techniques are based on density functional theory, the pseudopotential approximation, and plane-wave basis sets. The statistical-mechanical basis of the Green±Kubo relations is summarised, and extensive ®rst-principles molecular dynamics simulations of liquid aluminium are presented to demonstrate that the method works in practice. Calculated viscosity results are reported for two important systems: liquid iron at Earth's core conditions, and liquid selenium at states on the liquid±vapour curve. The signi®cance of the viscosity results for an understanding of these systems is discussed. Ó 1999 Elsevier Science B.V. All rights reserved.