Using conceptually and procedurally consistent density functional theory (DFT) calculations with an advanced meta-generalized gradient approximation (GGA) exchange-correlation functional in ab initio Born-Oppenheimer molecular dynamics (BOMD) simulations, we determine the insulator-metal transition (IMT) of warm dense fluid hydrogen from 50 to 300 GPa to be in better agreement with experiment than previous DFT predictions. The inclusion of nuclear quantum effects via path-integral molecular dynamics (PIMD) sharpens the transition and lowers its temperature relative to the BOMD results. A rapid decrease in the molecular character of the system, as observed via the ionic pair correlation function, coincides with an abrupt conductivity increase, confirming a metallic transition due to molecular hydrogen dissociation that is coincident with abrupt band-gap closure. Comparison of the PIMD and BOMD results clearly demonstrates an isotope effect on the IMT. Exploitation of differing methodologies for using the orbital-dependent and deorbitalized versions of the meta-GGA enables us to quantify exchange-correlation approximation effects. Distinct from stochastic simulations, these results do not depend upon any clever but uncontrolled combination of ground-state and finite-T methodologies and should provide a reliable benchmark for further studies.

中文翻译：

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完全稠密密度泛函理论确定温暖浓氢中绝缘子-金属的过渡边界

从头开始使用概念上和程序上一致的密度泛函理论（DFT）计算与高级元广义梯度逼近（GGA）交换-相关函数通过Born-Oppenheimer分子动力学（BOMD）模拟，我们确定从50 GPa到300 GPa的热致密流体氢的绝缘体-金属跃迁（IMT）与实验比以前的DFT预测更好地吻合。相对于BOMD结果，通过路径积分分子动力学（PIMD）包含核量子效应会加快过渡并降低其温度。如通过离子对相关函数所观察到的，系统分子特性的快速降低与电导率的突然增加相吻合，这证实了由于分子氢离解而引起的金属跃迁，这与突然的带隙闭合相吻合。PIMD和BOMD结果的比较清楚地表明了同位素对IMT的影响。利用不同的方法论来使用meta-GGA的轨道相关和去轨道化版本，使我们能够量化交换相关近似效应。与随机模拟不同，这些结果不依赖于基态和有限域的任何巧妙但不受控制的组合。T方法论，应为进一步研究提供可靠的基准。