Oxygen in the Earth's core:: a first-principles study
Oxygen in the Earth's core:: a first-principles study
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DOI：
10.1016/s0031-9201(98)00134-4
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发表时间：
1999-02-10
影响因子：
2.3
通讯作者：
Gillan, MJ
中科院分区：
文献类型：
--
作者：
Alfè, D;Price, GD;Gillan, MJ
基于密度泛函理论的第一性原理电子结构计算已被用来研究铁和氧的固溶体和液态合金在地核条件下的热力学，结构和输运性质。这项工作的目的是确定所需的氧浓度，以解释推断的外核密度，探测液体对相分离的稳定性，解释在液体中的键合，并找出是否粘度显着不同的纯液态铁在相同的条件下。结果表明，所需的氧浓度是在25-30摩尔%的区域，并在这些条件下的相稳定性的证据。Fe/O键是部分离子键，但具有较强的共价成分。其粘度低于地球核心条件下的纯液态铁。它表明，早期的第一性原理计算表明非常大的形成固溶体可能需要重新解释，因为假设的晶体结构是不是最稳定的氧浓度的兴趣。(C)1999 Elsevier Science B. V.保留所有权利。
First-principles electronic structure calculations based on DFT have been used to study the thermodynamic, structural and transport properties of solid solutions and liquid alloys of iron and oxygen at Earth's core conditions. Aims of the work are to determine the oxygen concentration needed to account for the inferred density in the outer core, to probe the stability of the liquid against phase separation, to interpret the bonding in the liquid, and to find out whether the viscosity differs significantly from that of pure liquid iron at the same conditions. It is shown that the required concentration of oxygen is in the region 25-30 mol%, and evidence is presented for phase stability at these conditions. The Fe/O bonding is partly ionic, but with a strong covalent component. The viscosity is lower than that of pure liquid iron at Earth's core conditions. It is shown that earlier first-principles calculations indicating very large enthalpies of formation of solid solutions may need reinterpretation, since the assumed crystal structures are not the most stable at the oxygen concentration of interest. (C) 1999 Elsevier Science B.V. All rights reserved.