Shrinking of Rapidly Evaporating Water Microdroplets Reveals their Extreme Supercooling
Shrinking of Rapidly Evaporating Water Microdroplets Reveals their Extreme Supercooling
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DOI：
10.1103/physrevlett.120.015501
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发表时间：
2018-01-02
影响因子：
8.6
通讯作者：
Grisenti, Robert E.
中科院分区：
文献类型：
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作者：
Goy, Claudia;Potenza, Marco A. C.;Grisenti, Robert E.
微米大小的水滴在真空中的快速蒸发冷却为在远高于最先进水平的温度下研究过冷水提供了诱人的可能性。过冷水低于熔点，但仍是液体。然而，在这样极端的实验条件下，要获得可靠的液滴温度值是具有挑战性的。在这里，通过观察一系列完美均匀的水滴的拉曼散射中与形态有关的共振，我们可以测量由于蒸发质量损失而导致的液滴大小的变化，绝对精度优于0.2%。事实证明，这一发现对于明确确定液滴温度至关重要。特别是，我们发现初始直径为6379+/-12 nm的一小部分水滴在230.6+/-0.6K以下仍然是液体。我们的结果质疑了最近报道的较大过冷水滴的温度估计，并提供了关于难以进入深度过冷区的液态水中氢键网络的有价值的信息。
The fast evaporative cooling of micrometer-sized water droplets in a vacuum offers the appealing possibility to investigate supercooled water-below the melting point but still a liquid-at temperatures far beyond the state of the art. However, it is challenging to obtain a reliable value of the droplet temperature under such extreme experimental conditions. Here, the observation of morphology-dependent resonances in the Raman scattering from a train of perfectly uniform water droplets allows us to measure the variation in droplet size resulting from evaporative mass losses with an absolute precision of better than 0.2%. This finding proves crucial to an unambiguous determination of the droplet temperature. In particular, we find that a fraction of water droplets with an initial diameter of 6379 +/- 12 nm remain liquid down to 230.6 +/- 0.6 K. Our results question temperature estimates reported recently for larger supercooled water droplets and provide valuable information on the hydrogen-bond network in liquid water in the hard-to-access deeply supercooled regime.