Iglev H, Schmeisser M, Simeonidis K, Thaller A, Laubereau A
Physik-Department, Technische Universität München, James-Franck-Strasse, D-85748 Garching, Germany.
Nature. 2006 Jan 12;439(7073):183-6. doi: 10.1038/nature04415.
The superheating of a solid to a temperature beyond its melting point, without the solid actually melting, is a well-known phenomenon. It occurs with many substances, particularly those that can readily be produced as high-quality crystals. In principle, ice should also be amenable to superheating. But the complex three-dimensional network of hydrogen bonds that holds water molecules together and gives rise to unusual solid and liquid properties strongly affects the melting behaviour of ice; in particular, ice usually contains many defects owing to the directionality of its hydrogen bonds. However, simulations are readily able to 'create' defect-free ice that can be superheated. Here we show that by exciting the OH stretching mode of water, it is possible to superheat ice. When using an ice sample at an initial temperature of 270 K, we observe an average temperature rise of 20 +/- 2 K that persists over the monitored time interval of 250 ps without melting.
将固体加热到超过其熔点的温度而固体实际上并未熔化，这是一种众所周知的现象。许多物质都会出现这种情况，特别是那些能够容易地制成高质量晶体的物质。原则上，冰也应该能够被过热。但是将水分子维系在一起并导致冰具有特殊的固体和液体性质的复杂三维氢键网络，强烈影响着冰的熔化行为；特别是，由于其氢键的方向性，冰通常含有许多缺陷。然而，模拟能够轻易地“创造”出可以被过热的无缺陷冰。在这里我们表明，通过激发水的OH伸缩模式，可以使冰过热。当使用初始温度为270 K的冰样品时，我们观察到在250 ps的监测时间间隔内平均温度升高20±2 K且没有熔化。
