 
Summary: Iron under Earth's core conditions:
Liquidstate thermodynamics and highpressure melting curve from ab initio calculations
D. Alfe`,1,2
G. D. Price,1
and M. J. Gillan2
1
Research School of Geological and Geophysical Sciences, Birkbeck and University College London, Gower Street, London WC1E 6BT,
United Kingdom
2
Physics and Astronomy Department, University College London, Gower Street, London WC1E 6BT, United Kingdom
Received 13 July 2001; revised manuscript received 22 January 2002; published 12 April 2002
Ab initio techniques based on density functional theory in the projectoraugmentedwave implementation are
used to calculate the free energy and a range of other thermodynamic properties of liquid iron at high pressures
and temperatures relevant to the Earth's core. The ab initio free energy is obtained by using thermodynamic
integration to calculate the change of free energy on going from a simple reference system to the ab initio
system, with thermal averages computed by ab initio molecular dynamics simulation. The reference system
consists of the inversepower pairpotential model used in previous work. The liquidstate free energy is
combined with the free energy of hexagonal close packed Fe calculated earlier using identical ab initio
techniques to obtain the melting curve and volume and entropy of melting. Comparisons of the calculated
melting properties with experimental measurement and with other recent ab initio predictions are presented.
