Dynamical stability of Fe-H in the Earth's mantle and core regions
The core extends from the depth of 2,900 km to the center of the Earth and is composed mainly of an iron-rich alloy with nickel, with 10% of the mass comprised of lighter elements like hydrogen, but the exact composition is uncertain. We present a quantum mechanical first-principles study of the dyn...
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Veröffentlicht in: | Proceedings of the National Academy of Sciences - PNAS 2007-05, Vol.104 (22), p.9168-9171 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The core extends from the depth of 2,900 km to the center of the Earth and is composed mainly of an iron-rich alloy with nickel, with 10% of the mass comprised of lighter elements like hydrogen, but the exact composition is uncertain. We present a quantum mechanical first-principles study of the dynamical stability of FeH phases and their phonon densities of states at high pressure. Our free-energy calculations reveal a phonon-driven stabilization of dhcp FeH at low pressures, thus resolving the present contradiction between experimental observations and theoretical predictions. Calculations reveal a complex phase diagram for FeH under pressure with a dhcp [rightward arrow] hcp [rightward arrow] fcc sequence of structural transitions. |
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ISSN: | 0027-8424 1091-6490 1091-6490 |
DOI: | 10.1073/pnas.0609701104 |