Equation of state and thermodynamic properties of liquid Fe-O in the Earth’s outer core  

作　　者：Miaoxu Xie Jie Fu Anatoly B.Belonoshko 

机构地区：[1]Institute of High Pressure Physics,School of Physical Science and Technology,Ningbo University,Ningbo 315211,China [2]Frontiers Science Center for Critical Earth Material Cycling,School of Earth Sciences and Engineering,Nanjing University,Nanjing 210026,China

出　　处：《Geoscience Frontiers》2025年第1期265-273,共9页地学前缘(英文版)

基　　金：supported by the National Natural Science Foundation of China(NSFC)(Grant No.11804175);the Program for Science and Technology Innovation Team in Zhejiang(Grant No.2021R01004);the Natural Science Foundation of Ningbo(Grant No.2021J099).

摘　　要：Equation of state(EoS)plays a crucial role in the prediction of the composition of the outer core.Here,we calculated pressure(P)-volume(V)-temperature(T)data of liquid iron-oxygen alloys(Fe-X wt.%O,X=0,2.8,6.1,and 9.9)under the outer core conditions(∼136-330 GPa,4000-6000 K)by first-principles molecular dynamics simulations.We established an EoS for liquid Fe-O alloys with parameters including P,T,V,and O concentrations.Consequently,thermodynamic properties of liquid Fe-O alloys such as density(ρ),thermal expansion coefficient,isothermal and adiabatic bulk modulus,and sound velocity(V_(P))are calculated.To constrain the O content,we predicted theρ-P and V_(P)-P profiles along the geotherm and compared them with data from the Preliminary Reference Earth Model(PREM).We conclude that the adiabatic T profile as a function of depth affects the prediction of O content dramatically.With several anchored TICB,the composition of Fe-6.1 wt.%O matches the PREM data with an acceptable range of error.But strictly speaking,the distribution in the outer core is probably uneven.In such case,we state that the O content in the outer core cannot be higher than approximately 6.1 wt.%.

关 键 词：Equation of state First-principles molecular dynamics Liquid iron-oxygen alloys Thermodynamic properties 

分 类 号：TG1[金属学及工艺—金属学]