近日，瑞典斯德哥尔摩大学Anders Nilsson团队揭示了过冷水中液-液临界点的实验证据。该项研究成果发表在2026年3月26日出版的《科学》杂志上。

由于快速结晶，在过冷水中寻找液-液临界点极具挑战性。

研究组通过红外超快激光脉冲加热高密度和低密度非晶态冰，在冰形成之前的时间尺度上利用X射线散射研究了过冷水。通过改变泵浦激光的通量，得以进入跨越预测临界点的液态区域。研究组观察到了从非连续转变到连续转变的过渡，在此过程中发生了广泛而缓慢的结构变化，与临界波动和减速相一致。研究组还观察到热容量的快速增加，表明在210 ± 8 K处存在临界发散，这与增强的密度涨落相吻合。这些结果表明，该实验直接探测到了过冷水中临界点附近的区域。

附：英文原文

Title: Experimental evidence of a liquid-liquid critical point in supercooled water

Author: Seonju You, Marjorie Ladd-Parada, Kyeongmin Nam, Aigerim Karina, Seoyoung Lee, Myeongsik Shin, Cheolhee Yang, Yeseul Han, Sangmin Jeong, Kichan Park, Kyeongwon Kim, Minjeong Ki, Robin Tyburski, Iason Andronis, Keely Ralf, Jae Hyuk Lee, Intae Eom, Minseok Kim, Rory Ma, Dogeun Jang, Fivos Perakis, Peter H. Poole, Katrin Amann-Winkel, Kyung Hwan Kim, Anders Nilsson

Issue&Volume: 2026-03-26

Abstract: The search for the liquid-liquid critical point in supercooled water is challenging owing to rapid crystallization. We studied supercooled water at timescales before ice formation by heating high- and low-density amorphous ices using infrared ultrafast laser pulses, followed by x-ray scattering. By varying the pump laser fluence, we accessed liquid states straddling the predicted critical point. We observed a crossover from a discontinuous to a continuous transition at which broad and slow structural variations occurred, consistent with critical fluctuations and slowing down. We also observed a rapid increase in the heat capacity indicating a critical divergence at 210 ± 8 K coincident with enhanced density fluctuations. These results suggest that our experiments have directly probed the vicinity of a critical point in supercooled water.

DOI: aec0018

Source: https://www.science.org/doi/10.1126/science.aec0018