The properties of dense hot hydrogen, in particular the phase transition between the molecular insulating and atomic conductive states, are important in the fields of astrophysics and high-pressure physics. Previous ab initio calculations suggested the metallization in liquid hydrogen, accompanied by dissociation, is a first-order phase transition and ends at a critical point in temperature range between 1500 and 2000 K and pressure close to 100 GPa. Using density functional theoretical molecular dynamics simulations, we report a first-principles equation of state of hydrogen that covers dissociation transition conditions at densities ranging from 0.20 to 1.00 g/cc and temperatures of 600 to 9000 K. Our results clearly indicate that a drop in pressure and a sharp structural change still occur as the system transforms from a diatomic to monoatomic phase at temperatures above 2000 K, and support the first-order phase transition in liquid hydrogen would end in the temperature about 4500 K.

中文翻译：

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液氢状态与解离跃迁的第一性原理方程

稠密热氢的性质，特别是分子绝缘态和原子导电态之间的相变，在天体物理学和高压物理学领域很重要。先前的从头计算表明，液态氢中的金属化伴随解离是一级相变，并在温度范围在 1500 到 2000 K 和压力接近 100 GPa 的临界点结束。使用密度泛函理论分子动力学模拟，我们报告了氢状态的第一性原理方程，该方程涵盖了密度范围为 0.20 至 1.00 g/cc 和温度为 600 至 9000 K 的解离转变条件。