Thermodynamics of hexagonal-close-packed iron under Earth's core conditions -: art. no. 045123

被引:254
作者
Alfè, D
Price, GD
Gillan, MJ
机构
[1] Univ London Birkbeck Coll, Res Sch Geol & Geophys Sci, London WC1E 6BT, England
[2] UCL, Dept Phys & Astron, London WC1E 6BT, England
来源
PHYSICAL REVIEW B | 2001年 / 64卷 / 04期
关键词
D O I
10.1103/PhysRevB.64.045123
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
The free energy and other thermodynamic properties of hexagonal-close-packed iron are calculated by direct ab initio methods over a wide range of pressures and temperatures relevant to the Earth's core. The ab initio calculations are based on density-functional theory in the generalized-gradient approximation, and are performed using the projector augmented wave approach. Thermal excitation of electrons is fully included. The Helmholtz free energy consists of three parts, associated with the rigid perfect lattice, harmonic lattice vibrations, and anharmonic contributions, and the technical problems of calculating these parts to high precision are investigated. The harmonic part is obtained by computing the phonon frequencies over the entire Brillouin zone, and by summation of the free-energy contributions associated with the phonon modes. The anharmonic part is computed by the technique of thermodynamic integration using carefully designed reference systems. Detailed results are presented for the pressure, specific heat, bulk modulus, expansion coefficient and Gruneisen parameter, and comparisons are made with values obtained from diamond-anvil-cell and shock experiments.
引用
收藏
页数:16
相关论文
共 71 条
[1]   First-principles calculation of transport coefficients [J].
Alfè, D ;
Gillan, MJ .
PHYSICAL REVIEW LETTERS, 1998, 81 (23) :5161-5164
[2]   Structure and dynamics of liquid iron under Earth's core conditions [J].
Alfè, D ;
Kresse, G ;
Gillan, MJ .
PHYSICAL REVIEW B, 2000, 61 (01) :132-142
[3]   First-principles simulations of liquid Fe-S under Earth's core conditions [J].
Alfe, D ;
Gillan, MJ .
PHYSICAL REVIEW B, 1998, 58 (13) :8248-8256
[4]   The melting curve of iron at the pressures of the Earth's core from ab initio calculations [J].
Alfè, D ;
Gillan, MJ ;
Price, GD .
NATURE, 1999, 401 (6752) :462-464
[5]  
Alfè D, 2000, INT J QUANTUM CHEM, V77, P871, DOI 10.1002/(SICI)1097-461X(2000)77:5<871::AID-QUA8>3.0.CO
[6]  
2-3
[7]   Oxygen in the Earth's core:: a first-principles study [J].
Alfè, D ;
Price, GD ;
Gillan, MJ .
PHYSICS OF THE EARTH AND PLANETARY INTERIORS, 1999, 110 (3-4) :191-210
[8]   MOLECULAR-DYNAMICS SIMULATIONS AT CONSTANT PRESSURE AND-OR TEMPERATURE [J].
ANDERSEN, HC .
JOURNAL OF CHEMICAL PHYSICS, 1980, 72 (04) :2384-2393
[9]  
Anderson O. L., 1995, OXFORD MONOGRAPHS GE, V31
[10]   The orthorhombic structure of iron: An in situ study at high-temperature and high-pressure [J].
Andrault, D ;
Fiquet, G ;
Kunz, M ;
Visocekas, F ;
Hausermann, D .
SCIENCE, 1997, 278 (5339) :831-834