Zhang Jurong, Liu Hanyu, Ma Yanming, Chen Changfeng
International Center for Computational Method and Software & State Key Laboratory of Superhard Materials & Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, China.
Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154, USA.
Natl Sci Rev. 2021 Sep 2;9(7):nwab168. doi: 10.1093/nsr/nwab168. eCollection 2022 Jul.
Hydrogen and helium are known to play crucial roles in geological and astrophysical environments; however, they are inert toward each other across wide pressure-temperature (P-T) conditions. 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 FeOHHe stabilized in a wide range of P-T conditions. molecular dynamics simulations further reveal a novel superionic state of FeOHHe hosting liquid-like diffusive hydrogen in the FeOHe sublattice, creating a conducive environment for H-He chemical association, at P-T conditions corresponding to the Earth's lowest mantle regions. To our surprise, this 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.
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，在很宽的压力-温度（P-T）条件范围内，它们彼此呈惰性。鉴于它们在天体形成和演化过程中的显著存在及影响，探索氢与氦之间相互作用的本质具有根本重要性。利用一种先进的晶体结构搜索方法，我们已确定了一种在很宽的P-T条件范围内稳定存在的四元化合物FeOHHe。分子动力学模拟进一步揭示，在对应于地球最下地幔区域的P-T条件下，FeOHHe呈现一种新型超离子态，在FeOHe亚晶格中存在类似液体扩散的氢，为H-He化学缔合创造了有利环境。令我们惊讶的是，这种原本不互溶的分子物种通过化学作用促进的聚结，为探索这种长期寻求但迄今无法实现的物质状态开辟了一条有前景的途径。这一发现为地球内部以及可能在其他天体中存在奇异的H-He混合物带来了很大希望。
