Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA.
J Chem Phys. 2018 Apr 14;148(14):144503. doi: 10.1063/1.5004985.
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.
使用 BLYPSP-4F 水势能，通过分子动力学模拟研究了纳米级水滴的表面张力。通过在 1 到 1000 巴的压力范围内进行一系列的整体模拟，建立了压力和密度之间的经验关系，从而测量了液滴的内部压力。这种方法不需要计算局部维里，就可以可靠地确定内部压力。通过杨氏-拉普拉斯关系估算的表面张力与托马长度为-0.48 Å 的托马方程吻合较好。根据半径的不同，液态水液滴的界面厚度约为 1.1-1.3nm。相当厚的界面区域对仍然具有类似体相内部的液滴的大小施加了下限。
