Transport coefficients of liquids from first principles

The use of first-principles molecular dynamics to calculate the viscosity o f liquid metals using the Green-Kubo relations is described. The first-prin ciples techniques are based on density functional theory the pseudopotentia l approximation, and plane-wave basis sets. The statistical-mechanical basi s of the Green-Kubo relations is summarised, and extensive first-principles molecular dynamics simulations of liquid aluminium are presented to demons trate that the method works in practice. Calculated viscosity results are r eported for two important systems: liquid iron at Earth's core conditions, and liquid selenium at states on the liquid-vapour curve. The significance of the viscosity results for an understanding of these systems is discussed . (C) 1999 Elsevier Science B.V. All rights reserved.