Institute of Low Temperature Science, Hokkaido University, Kita-19, Nishi-8, Kita-ku, Sapporo 060-0819, Japan.
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
J Phys Chem Lett. 2022 May 19;13(19):4251-4256. doi: 10.1021/acs.jpclett.2c00660. Epub 2022 May 11.
Experimental confirmation of liquid polymorphs of water, high-density liquid (HDL) and low-density liquid (LDL), is desired for understanding not only the liquid state of matter but also the origin of the mysterious properties of water. However, this remains challenging because the liquid-liquid critical point of water lies in experimentally inaccessible supercooling conditions known as "no man's land". Here, we show by optical microscopy that droplets and layers of low- and high-density unknown waters (LDUW and HDUW) appear macroscopically depending upon ice polymorphs at non-equilibrium interfaces between water and ices under experimentally accessible (de)pressurization conditions. These unknown waters were found to have characteristic velocities (about 20 and 100 m/s for LDUW and HDUW, respectively) different from water (about 40 m/s) and quasi-liquid layers (QLLs) (about 2 and 0.2 m/s for droplet and layer forms of QLLs, respectively). Our discoveries provide insight on liquid polymorphism of water.
需要对水的液相变体、高密度液体 (HDL) 和低密度液体 (LDL) 进行实验证实，这不仅有助于理解物质的液相状态，还有助于理解水的神秘性质的起源。然而，这仍然具有挑战性，因为水的液-液相临界点位于实验上无法到达的过冷条件，称为“无人区”。在这里，我们通过光学显微镜表明，在实验上可达到的（减压）条件下，水和冰之间的非平衡界面处，冰的多晶型会导致低密度和高密度未知水（LDUW 和 HDUW）的液滴和层宏观出现，这些未知水具有与水（约 40 m/s）和准液态层（QLL）不同的特征速度（LDUW 和 HDUW 分别约为 20 和 100 m/s，QLL 的液滴和层形式分别约为 2 和 0.2 m/s）。我们的发现为水的液相多晶型提供了新的见解。
