Yan Xiaozhen, Chen Yangmei, Kuang Xiaoyu, Xiang Shikai
Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan 610065, China.
National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, P.O. Box 919-111, Mianyang, Sichuan 621900, China.
J Chem Phys. 2015 Sep 28;143(12):124310. doi: 10.1063/1.4931931.
Application of high pressure can substantially enhance the chemical reactivity of xenon and has recently extended the Xe-compounds to unexpected elements such as Fe and H. Using unbiased structure searching techniques combined with first-principles calculations, we predict novel compounds of stable XeH2 and XeH4, and metastable XeH, XeH3, XeH5, XeH6, XeH7, and XeH8 under high pressure. Rather than van der Waals complexes, these are weakly covalent or ionic compounds stabilized by a pressure-induced increase in charge transfer from Xe to H atoms. The calculated electronic structures with hybrid exchange-correlation functionals reveal that only XeH and XeH2 are metalized under 300 GPa. For the metallic XeH and XeH2 at certain pressures, the superconducting critical temperatures are finally studied, by using Allen-Dynes modified McMillan equation combined with the calculated electron-phonon coupling parameter.
高压的应用能够显著提高氙的化学反应活性，并且最近已将含氙化合物扩展到诸如铁和氢等意想不到的元素。通过结合第一性原理计算的无偏结构搜索技术，我们预测了在高压下稳定的XeH₂和XeH₄以及亚稳的XeH、XeH₃、XeH₅、XeH₆、XeH₇和XeH₈等新型化合物。这些并非范德华络合物，而是通过压力诱导的从氙到氢原子的电荷转移增加而稳定的弱共价或离子化合物。采用杂化交换关联泛函计算的电子结构表明，在300 GPa以下只有XeH和XeH₂会金属化。对于在特定压力下的金属态XeH和XeH₂，最终通过使用艾伦 - 戴恩斯修正的麦克米兰方程结合计算得到的电子 - 声子耦合参数研究了其超导临界温度。
