Widom line and dynamical crossovers as routes to understand supercritical water
Widom line and dynamical crossovers as routes to understand supercritical water
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DOI：
10.1038/ncomms6806
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发表时间：
2014-12-01
影响因子：
16.6
通讯作者：
Rovere, M.
中科院分区：
文献类型：
--
作者：
Gallo, P.;Corradini, D.;Rovere, M.
超临界水是许多应用领域的基础，超临界状态的精确表征对于这种液体至关重要。在流体中，当从临界点移动到单相区域时，热力学响应函数显示出极大值，让人想起临界发散。在这里，我们通过分析现有的实验数据和计算机模拟结果来研究超临界区域水的热力学性质。我们发现连接响应函数最大值的线收敛于一条线（Widom 线），接近临界点。我们进一步表明，Widom 线与传输特性中清晰可见的从类液体到类气体行为的交叉一致。这些热力学和动力学特征表明，水中的超临界状态比迄今为止所认为的要复杂得多，这表明了该状态热力学表征的新视角。
Supercritical water is fundamental in many fields of applications and a precise characterization of the supercritical state is of uttermost importance for this liquid. In a fluid, when moving from the critical point into the single-phase region, the thermodynamic response functions show maxima reminiscent of the critical divergence. Here we study the thermodynamic properties of water in the supercritical region by analysing both available experimental data and our computer simulation results. We find that the lines connecting the maxima of the response functions converge on approaching the critical point in a single line, the Widom line. We further show that the Widom line coincides with a crossover from a liquid-like to a gas-like behaviour clearly visible in the transport properties. These thermodynamic and dynamic features show that the supercritical state in water is far more complex than what was so far believed, indicating a new perspective in the characterization of the thermodynamics of this state.