Phase transitions of ices XIV, XV and XIV have not been confirmed by experiment or high-precision theory due to the kinetic barriers. We use ab initio method to calculate the Gibbs free energies of ices XIV, XV, and VIII, and predict their crystal structures and phase transitions at high pressure and low temperatures, based on second-order Møller-Plesset perturbation theory. The proposed model predict that the triple point of phase transition of ices XIV, XV and VIII occurs at about 1.258 GPa and 112 K, which agrees with the experimental speculation and provides an effective method for explorations of new solid-state structures.

中文翻译：

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XV / XIV / VIII冰在高压和低温下的从头算相变预测

由于动力学障碍，尚未通过实验或高精度理论确认冰XIV，XV和XIV的相变。基于二阶Møller-Plesset微扰理论，我们使用从头算方法来计算冰XIV，XV和VIII的吉布斯自由能，并预测它们在高压和低温下的晶体结构和相变。所提出的模型预测，冰XIV，XV和VIII的相变三点出现在约1.258 GPa和112 K处，这与实验推测相符，并为探索新的固态结构提供了有效的方法。