The surface tension of nanoscale droplets of water was studied with molecular dynamics simulations using the BLYPSP-4F water potential. The internal pressure of the droplet was measured using an empirical correlation between the pressure and density, established through a series of bulk simulations performed at pressures from 1 to 1000 bars. Such a procedure allows for reliable determination of internal pressure without the need to calculate the local virial. The surface tension, estimated with the Young-Laplace relation, shows good agreement with the Tolman equation with a Tolman length of −0.48 Å. The interface of a liquid water droplet is shown to be around 1.1–1.3 nm thick depending on radii. The fairly thick interface region puts a lower limit on the size of droplets that still have a bulk-like interior.

中文翻译：

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纳米水滴表面张力的分子动力学研究及通过密度相关法测定局部压力的新技术

使用BLYPSP-4F水势，通过分子动力学模拟研究了纳米级水滴的表面张力。使用在压力和密度之间的经验相关性来测量液滴的内部压力，该经验相关性是通过在1至1000 bar的压力下进行的一系列总体模拟建立的。这样的程序允许可靠地确定内部压力，而无需计算局部病毒。用杨-拉普拉斯关系估计的表面张力与托尔曼长度为-0.48的托尔曼方程显示出良好的一致性。根据半径的不同，水滴的界面厚度约为1.1–1.3 nm。相当厚的界面区域对仍然具有大块状内部的液滴的大小设置了下限。