A MOLECULAR-BEAM STUDY OF THE EVAPORATION OF WATER FROM A LIQUID JET
A MOLECULAR-BEAM STUDY OF THE EVAPORATION OF WATER FROM A LIQUID JET
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DOI：
10.1007/bf01384861
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发表时间：
1988-01-01
期刊：
影响因子：
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通讯作者：
TOENNIES, JP
中科院分区：
文献类型：
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作者：
FAUBEL, M;SCHLEMMER, S;TOENNIES, JP
描述了一种在高真空中保持液体的清洁表面的方法。使用非常薄和快速的液体射流，不仅可以防止液体冻结，而且可以将蒸发分子之间的碰撞次数减少到可以忽略的小值。因此，许多标准的，真空依赖，固体表面的粒子探测技术可以用于快速蒸发，高蒸汽压液体的研究。在第一个分子束调查中，我们已经使用飞行时间分析来测量从纯液态水的薄射流蒸发的H2O分子的速度分布。实验是针对50至5 µm之间的液体射流直径进行的。在这个范围内，膨胀的蒸汽被观察到进行过渡到无碰撞的分子流制度。从测量的速度分布，局部表面温度被确定为小于210 K。这似乎是有史以来报道过冷液态水的最低温度。
A method to maintain a clean surface of a liquid in a high vacuum is described. Using a very thin and fast liquid jet it is not only possible to prevent freezing of the liquid but also to reduce the number of collisions between evaporating molecules to negligibly small values. Thus many of the standard, vacuum dependent, particle probing techniques for solid surfaces can be used for studies of rapidly vaporizing, high vapor pressure liquids. In a first molecular beam investigation we have used time-of-flight analysis to measure the velocity distribution of H2O molecules vaporizing from thin jets of pure liquid water. The experiments were carried out for liquid jet diameters between 50 and 5 µm. In this range the expanding vapor is observed to undergo the transition to the collision-free molecular flow regime. From the measured velocity distributions the local surface temperature is determined to be less than 210 K. This appears to be the lowest temperature ever reported for supercooled liquid water.