A first-principles molecular dynamics study of molecular hydrogen diffusion in Fe-free olivine  

作　　者：Haibo Liu Baohua Zhang Hongzhan Fei Lei Liu 

机构地区：[1]School of Earth Sciences,Zhejiang University,Hangzhou 310027,China [2]United Laboratory of High-Pressure Physics and Earthquake Science,Institute of Earthquake Forecasting,Chinese Earthquake Administration,Beijing 100036,China

出　　处：《Geoscience Frontiers》2025年第1期347-353,共7页地学前缘(英文版)

基　　金：supported by the National Natural Science Foundation of China for Distinguished Young Scholars(42325203).

摘　　要：Molecular hydrogen(H_(2))may be an important form of water in nominally anhydrous minerals in the Earth’s mantle and plays a critical role in mantle water cycle,but the transport properties of H2 remain unclear.Here,the diffusion of H2 in Fe-free olivine lattice is investigated at pressures of 1-13 GPa and temperatures of 1300-1900 K by first-principles molecular dynamics.The activation energy and activation volume for H2 diffusion in Fe-free olivine are determined to be 55±8 kJ/mol and 3.6±0.2 cm3/mol,respectively.H2 diffusion in Fe-free olivine is faster than H+by 1-4 orders of magnitude and therefore it is more favorable for hydrogen transportation under upper mantle conditions.H2 can be carried to the mantle transition zone by subducting slabs without releasing to the surrounding mantle.The upper mantle may act as a lid,preventing the releasing of H2 produced in the deep mantle to the surface.

关 键 词：First principles calculations Molecular dynamics Molecular hydrogen Diffusion coefficient OLIVINE Upper mantle 

分 类 号：P58[天文地球—岩石学]