发表机构
The Abdus Salam International Centre for Theoretical Physics（阿卜杜斯·萨拉姆国际理论物理中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过机器学习势模拟和TNM模型，证明过冷水超快加热中的热容增加源于玻璃化转变的动力学效应，而非液体-液体临界点，为实验提供了新解释。
AI 中文摘要
水的反常性质被假设源于过冷区域中的一个液体-液体临界点，该临界点将高密度和低密度液态区分开来。由于这些条件下的快速结晶，实验验证仍然具有挑战性。最近的一项研究报告了此类转变的证据，主要基于快速加热的低密度非晶冰的热容显著增加。在此，我们表明这种热容增加可以在不涉及液体-液体转变的情况下得到解释。通过结合使用基于最先进的MB-pol水模型训练的机器学习势的模拟，并与玻璃化转变的Tool-Narayanaswamy-Moynihan（TNM）模型相结合，我们证明了观察到的信号可能反而源于超快加热过程中旋转和平移分子自由度活化所诱导的动力学效应。我们进一步表明，我们的发现与最近的电子衍射测量完全一致，这些测量显示过冷水在我们预测的玻璃化转变温度附近发生结构停滞。这些结果为实验观察提供了另一种解释，并强调了非平衡玻璃态动力学在解释超短时间尺度上过冷水行为中的重要性。
英文摘要
Water's anomalous properties have been hypothesized to originate from a liquid-liquid critical point in the supercooled regime, separating high- and low-density liquid states. Experimental verification remains challenging due to rapid crystallization under these conditions. A recent study reported evidence for such a transition, based primarily on a pronounced increase in the heat capacity of rapidly heated low-density amorphous ice. Here, we show that this heat capacity increase can be explained without invoking a liquid-liquid transition. By combining simulations using a machine-learning potential trained on the state-of-the-art MB-pol water model, combined with the Tool-Narayanaswamy-Moynihan (TNM) model of the glass transition, we demonstrate that the observed signal can arise instead from a dynamical effect induced by the mobilization of rotational and translational molecular degrees of freedom during ultrafast heating. We further show that our findings are fully consistent with recent electron diffraction measurements showing structural arrest of supercooled water close to our predicted glass-transition temperature. These results provide an alternative interpretation of the experimental observations and highlight the importance of nonequilibrium glassy dynamics in the interpretation of the behavior of supercooled water on ultra-short time scales.
