热致密氨中的氢重组
Hydrogen Reorganization in Hot Dense Ammonia
- Institute of Atomic and Molecular Physics, Sichuan University（四川大学原子与分子物理研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过激光加热金刚石压砧实验，在高温高压下观察到氨转变为不透明相，结合第一性原理计算识别为离子NH$_7$相，揭示了热致密氨中氢重组驱动的新离子转变路径。
AI中文摘要：
已知氢在高压下能与多种简单分子固体形成稳定化合物。然而，氨氢化物尚未被实验观察到。在此，通过一系列激光加热金刚石压砧（LHDAC）实验，我们观察到透明的离子态氨在150 GPa和1000 K以上转变为不透明相。拉曼光谱揭示了显著的结构变化，伴随着两个不同的不对称H$_2$振动子（$\nu_1$和$\nu_2$）的出现。在热致密氨中，热诱导解离和氢重组产生了一个新的离子相。实验结果与第一性原理计算的结合将该相识别为理论上预测的NH$_7$的离子$P4_12_12$相，该相由NH$_4^+$、H$^-$和H$_2$单元组成。我们的结果表明，氨氢化物的形成遵循一条不同于其他含H$_2$混合物的热力学路径，揭示了在热致密氨中由氢重组驱动的新离子转变路径。
英文摘要：
Hydrogen is known to form stable compounds with a variety of simple molecular solids under high pressure. However, ammonia hydride has not been experimentally observed. Here, through a series of laser-heating diamond anvil cell (LHDAC) experiments, we observed the transparent ionic ammonia transformed into an opaque phase above 150 GPa and 1000 K. Raman spectroscopy reveals a pronounced structural change, accompanied by the emergence of two distinct asymmetric H$_2$ vibrons ($ν_1$ and $ν_2$). A new ionic phase produced following thermally induced dissociation and hydrogen reorganization in hot dense ammonia. The combination of experimental results and first-principles calculations identify this phase as the theoretically predicted ionic $P4_12_12$ phase of NH$_7$ , which consists of NH$_4^+$, H$^-$and H$_2$ units. Our results suggest that the formation of ammonia hydrides follows a thermodynamic pathway distinct from those of other H$_2$-containing mixtures, revealing a new ionic transformation pathway driven by hydrogen reorganization in hot dense ammonia.
