Institute of Physics and Materials Science, University of Natural Resources and Life Sciences, Peter Jordan Strasse 82, A-1190 Vienna, Austria.
Department of Chemistry, Eszterhazy Karoly University, Leanyka utca 6, H-3300 Eger, Hungary.
Soft Matter. 2023 May 31;19(21):3773-3782. doi: 10.1039/d3sm00176h.
Investigating the structure of fluid interfaces at high temperatures is a particularly delicate task that requires effective ways of discriminating liquid from vapour and identifying the location of the liquid phase boundary, thereby allowing to distinguish intrinsic from capillary fluctuations. Several numerical approaches require introducing a coarse-graining length scale, often heuristically chosen to be the molecular size, to determine the location of the liquid phase boundary. Here, we propose an alternative rationale for choosing this coarse-graining length scale; we require the average position of the local liquid phase dividing surface to match its flat, macroscopic counterpart. We show that this approach provides additional insight into the structure of the liquid/vapour interface, suggesting the presence of another length scale beyond the bulk correlation one that plays an important role in determining the interface structure.
研究高温下流体界面的结构是一项特别精细的任务，需要有效的方法来区分液体和蒸汽，并确定液相边界的位置，从而能够区分固有波动和毛细波动。几种数值方法需要引入一个粗粒化长度尺度，通常是凭经验选择为分子大小，以确定液相边界的位置。在这里，我们提出了一种选择这种粗粒化长度尺度的替代原理；我们要求局部液相分界面的平均位置与其平坦的宏观对应物相匹配。我们表明，这种方法为液体/蒸汽界面的结构提供了额外的见解，表明存在另一个长度尺度，超出了决定界面结构的体相关长度尺度。
