The knowledge of the structures that can exist in compounds containing helium is of interest for understanding the conditions where and if inert element can form stable compounds where closed shell electrons of helium can participate in bonding that is not describable exclusively by van der Waals interactions alone. In this work, we examine some mixtures of He and H2O, N2 or some minerals at high pressures using a first-principles structure searching method (CALYPSO). We find some thermodynamically stable structures under pressure[1-3]. These mechanically and dynamically stable structures are found at pressures that are now becoming accessible to high-pressure technique. The present results offer insights for the understanding of the plausible reaction between helium with minerals in the Earth’s or other exoplanetary interiors.
References:
[1] Hanyu Liu, Yansun Yao and Dennis Klug, “Stable structures of He and H2O at high pressure”, Phys. Rev. B 91, 014102 (2015)
[2] Yinwei Li, Xiaolei Feng, Hanyu Liu, Jian Hao, Simon A.T. Redfern, Weiwei Lei, Dan Liu, Yanming Ma, "Route to high-energy density polymeric nitrogen t-N via He-N compounds" , Nature Communication 9, 722 (2018)
[3] Jurong Zhang, Jian Lv, Hefei Li, Xiaolei Feng, Simon A.T. Redfern, Cheng Lu, Hanyu Liu, Changfeng Chen, Yanming Ma, "Rare helium-bearing compound FeO2He stabilized at deep-earth conditions", Phys. Rev. Lett. 121, 255703 (2018)