Despite water being the most common and most widely studied substance in the world, it still presents unknown aspects. In particular, water shows several thermodynamic and dynamical anomalies in the liquid and supercooled metastable phases, and the natures of these phases are still hotly debated. Here, we report measurements of water using the optical Kerr effect as a function of pressure along two isotherms, at 273 K from 0.1 to 750 MPa and at 297 K from 0.1 to 1350 MPa, reaching the supercooled metastable phase. The structural relaxation and the low frequency vibrational dynamics of water show a peculiar pressure dependence similar to that of other dynamical properties. The data analysis suggests the presence in the water phase diagram of a crossover area that divides two regions characterized by different dynamic regimes, which appear to be related to two liquid forms, one dominated by the high density water and the other by the low density water.

中文翻译：

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时间分辨光学克尔效应对水动力学的压力影响

尽管水是世界上最常见和研究最广泛的物质，但它仍然存在未知的方面。特别是，水在液相和过冷的亚稳相中表现出若干热力学和动力学异常，这些相的性质仍是热门话题。在这里，我们报告了使用光学克尔效应作为水沿着两个等温线的函数的测量结果，两个等温线在0.1 K到MPa的273 K下以及0.1到1350 MPa的297 K上达到过冷亚稳相。水的结构弛豫和低频振动动力学表现出与其他动力学特性相似的独特压力依赖性。数据分析表明，水相图中存在一个交叉区域，该区域将两个区域划分为以不同的动态状态为特征，