Malek Shahrazad M A, Sciortino Francesco, Poole Peter H, Saika-Voivod Ivan
Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, A1B 3X7, Canada.
J Phys Condens Matter. 2018 Apr 11;30(14):144005. doi: 10.1088/1361-648X/aab196. Epub 2018 Feb 22.
We calculate the components of the microscopic pressure tensor as a function of radial distance r from the centre of a spherical water droplet, modelled using the TIP4P/2005 potential. To do so, we modify a coarse-graining method for calculating the microscopic pressure (Ikeshoji et al 2003 Mol. Simul. 29 101) in order to apply it to a rigid molecular model of water. As test cases, we study nanodroplets ranging in size from 776 to 2880 molecules at 220 K. Beneath a surface region comprising approximately two molecular layers, the pressure tensor becomes approximately isotropic and constant with r. We find that the dependence of the pressure on droplet radius is that expected from the Young-Laplace equation, despite the small size of the droplets.
我们使用TIP4P/2005势对球形水滴进行建模，计算了微观压力张量的分量作为距水滴中心径向距离r的函数。为此，我们修改了一种用于计算微观压力的粗粒化方法（Ikeshoji等人，2003年，《分子模拟》，29卷，第101页），以便将其应用于水的刚性分子模型。作为测试案例，我们研究了在220K下大小从776到2880个分子不等的纳米液滴。在包含大约两个分子层的表面区域之下，压力张量随r近似各向同性且恒定。我们发现，尽管液滴尺寸很小，但压力对液滴半径的依赖性符合杨-拉普拉斯方程的预期。
