Anomalous Behavior of the Homogeneous Ice Nucleation Rate in "No-Man's Land".
Anomalous Behavior of the Homogeneous Ice Nucleation Rate in "No-Man's Land".
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DOI：
10.1021/acs.jpclett.5b01164
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发表时间：
2015-07-16
期刊：
影响因子：
--
通讯作者：
Nilsson A
中科院分区：
文献类型：
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作者：
Laksmono H;McQueen TA;Sellberg JA;Loh ND;Huang C;Schlesinger D;Sierra RG;Hampton CY;Nordlund D;Beye M;Martin AV;Barty A;Seibert MM;Messerschmidt M;Williams GJ;Boutet S;Amann-Winkel K;Loerting T;Pettersson LG;Bogan MJ;Nilsson A
我们通过以 103-104 K/s 的速度蒸发冷却微米大小的液滴（微滴），并使用来自直线加速器相干光源 (LCLS) 自由电子 X 射线激光器的飞秒脉冲超快探测结构，分析了当温度降至均质极限 TH 以下时，近环境压力水的冰成核动力学。在低于 232 K 的温度下，我们观察到随着温度降低，成核速率增加的速度比之前测量的预期要慢，我们认为这是由于水的扩散率迅速下降所致。这与早期的发现一致，即微滴在 <227 K 时不会结晶，但在 106-107 K/s 的冷却速率下会玻璃化。我们还假设成核速率的较慢增加与水中所提出的“从脆到强”的转变异常有关。
We present an analysis of ice nucleation kinetics from near-ambient pressure water as temperature decreases below the homogeneous limit TH by cooling micrometer-sized droplets (microdroplets) evaporatively at 103–104 K/s and probing the structure ultrafast using femtosecond pulses from the Linac Coherent Light Source (LCLS) free-electron X-ray laser. Below 232 K, we observed a slower nucleation rate increase with decreasing temperature than anticipated from previous measurements, which we suggest is due to the rapid decrease in water’s diffusivity. This is consistent with earlier findings that microdroplets do not crystallize at <227 K, but vitrify at cooling rates of 106–107 K/s. We also hypothesize that the slower increase in the nucleation rate is connected with the proposed “fragile-to-strong” transition anomaly in water.