Hydrogen and helium were known to play crucial roles in geological and astrophysical environments; however, they are inert toward each other across wide pressure-temperature (P-T). Given their prominent presence and influence on the formation and evolution of celestial bodies, it is of fundamental interest to explore the nature of interactions between hydrogen and helium. Using an advanced crystal structure search method, we have identified a quaternary compound FeO2H2He stabilized in a wide range of P-T conditions. Ab initio molecular dynamics simulations further reveal a novel superionic state of FeO2H2He hosting liquid-like diffusive hydrogen in the FeO2He sublattice, creating a conducive environment for H-He chemical association, at P-T conditions corresponding to the Earth's lowest mantle regions. This surprising chemically facilitated coalescence of otherwise immiscible molecular species highlights a promising avenue for exploring this long-sought but hitherto unattainable state of matter. This finding raises strong prospects for exotic H-He mixtures inside Earth and possibly also in other astronomical bodies.

中文翻译：

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深地条件下超离子 FeO2H2He 中的直接 H-He 化学缔合

众所周知，氢和氦在地质和天体物理环境中起着至关重要的作用；然而，它们在很宽的压力-温度 (PT) 范围内对彼此是惰性的。鉴于它们的突出存在和对天体形成和演化的影响，探索氢和氦之间相互作用的性质具有根本意义。使用先进的晶体结构搜索方法，我们确定了在广泛的 PT 条件下稳定的四元化合物 FeO2H2He。从头算分子动力学模拟进一步揭示了 FeO2H2He 的一种新的超离子态，在 FeO2He 亚晶格中含有液态扩散氢，在对应于地球最低地幔区域的 PT 条件下为 H-He 化学缔合创造了有利的环境。这种令人惊讶的化学促进原本不混溶的分子物种的聚结突出了探索这种长期寻求但迄今为止无法实现的物质状态的有希望的途径。这一发现为地球内部以及可能在其他天体中的奇异 H-He 混合物提出了强烈的前景。