In their recent communication, Tao and Mo [Phys. Rev. Lett. 117, 073001 (2016)] presented a semi-local density functional derived from the density matrix expansion of the exchange hole localized by a general coordinate transformation. We show that the order-of-limits problem present in the functional, dismissed as harmless in the original publication, causes severe errors in predicted phase transition pressures. We also show that the claim that lattice volume prediction accuracy exceeds that of existing similar functionals was based on comparison to reference data that miss anharmonic zero-point expansion and consequently overestimates accuracy. By highlighting these omissions, we give a more accurate assessment of the Tao–Mo functional and show a possible direction for resolving the order-of-limits problem.

中文翻译：

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检查Tao-Mo功能的极限顺序问题和晶格常数性能。

陶和莫[Phys。牧师 117，073001（2016）]提出了一种半局部密度从用一般的局部交换孔的密度矩阵扩展的坐标变换功能的。我们显示功能中存在的极限顺序问题，在原始出版物中被视为无害，在预测的相变压力中会导致严重错误。我们还表明，晶格体积预测精度超过现有相似功能的说法是基于与缺少非谐波零点展开并因此高估了准确性的参考数据的比较。通过突出显示这些遗漏，我们对Tao-Mo功能进行了更准确的评估，并显示了解决极限顺序问题的可能方向。