Geophysical and geochemical evidence suggests that Earth's core is predominantly made of iron (or iron-nickel alloy) with several percent of light elements. However, Earth's solid inner core transmits shear waves at a much lower velocity than expected from mineralogical models that are consistent with geochemical constraints. Here we investigate the effect of hydrogen on the elastic properties of iron and iron-silicon alloys using ab initio molecular dynamic simulations. We find that these H-bearing alloys maintain a superionic state under inner-core conditions and that their shear moduli exhibit a strong shear softening due to the superionic effect, with a corresponding reduction in $V_S$. Several hcp-iron-silicon-hydrogen compositions can explain the observed density, $V_P$, $V_S$, and Poisson's ratio of the inner core simultaneously. Our results indicate that hydrogen is a significant component of the Earth's core, and that it may contain at least four ocean masses of water. This indicates that the Earth may have accreted wet and obtained its water from chondritic and/or nebular materials before or during core formation.

地球物理和地球化学证据表明，地核主要由铁（或铁镍合金）和百分之几的轻元素构成。然而，地球的固体内核以比符合地球化学约束的矿物学模型预期的低得多的速度传输横波。在这里，我们使用从头算分子动力学模拟研究了氢对铁和铁硅合金弹性性能的影响。我们发现这些含氢合金在内核条件下保持超离子状态，并且由于超离子效应，它们的剪切模量表现出强烈的剪切软化，相应地减少了${伏}_{秒}$. 几个hcp -铁 - 硅 - 氢成分可以解释观察到的密度，${伏}_{磷}$, ${伏}_{秒}$, 和内核的泊松比同时存在。我们的研究结果表明，氢是地核的重要组成部分，它可能包含至少四个海洋质量的水。这表明地球在地核形成之前或期间可能已经湿吸积并从球粒陨石和/或星云材料中获得水。