Controlling the water contact angle on a surface is important for regulating its wettability in industrial applications, which involves developing ab initio prediction scheme of accurately predicting the angle. The scheme requires structural models for the adsorption of liquid molecules on a surface, but their reliability depend on whether the surfaces comprise insulating or metallic materials. Previous ab initio studies have focused on the estimation of the water contact angle on insulators, where the periodic-honeycomb array of water molecules was adopted as the adsorption model for the water on the insulating surface and succeeded in the insulating cases. This study, however, focuses on the water contact angle on a metallic surface, and proposes a simple ab initio based estimation scheme. We not only adopt the previously proposed structural modeling based on the periodic-honeycomb array, but also consider an ensemble of isolated water oligomers that have different molecular coverage (ML) values. We established a statistic model to predict a contact angle of the water wetting on a Cu(111) surface: The coverage-dependent contact angles obtained from each of the isolated clusters were fit to a quadratic regression, and the contact angle was interpolated by referring to a ML value of water layer in literature. This interpolated value lies within the deviation of experimental angles. In addition, the Boltzmann-average over the isolated clusters was found to agree well with the interpolated one. This indicates that the Boltzmann-average is useful for estimating the contact angle of other metallic surfaces without knowing a ML value a priori.

控制表面上的水接触角对于调节其在工业应用中的润湿性很重要，这涉及开发准确预测角度的从头算预测方案。该方案需要用于在表面上吸附液体分子的结构模型，但它们的可靠性取决于表面是否包含绝缘材料或金属材料。以前的从头算研究主要集中在绝缘体上水接触角的估计上，其中采用周期性蜂窝状水分子阵列作为绝缘表面水的吸附模型，并在绝缘情况下取得了成功。然而，这项研究侧重于金属表面上的水接触角，并提出了一个简单的从头算基于估计方案。我们不仅采用了先前提出的基于周期性蜂窝阵列的结构建模，而且还考虑了具有不同分子覆盖 (ML) 值的孤立水低聚物的集合。我们建立了一个统计模型来预测水润湿在 Cu(111) 表面上的接触角：从每个孤立的簇获得的覆盖依赖接触角拟合二次回归，接触角通过参考插值为文献中水层的 ML 值。该内插值位于实验角度的偏差范围内。此外，发现孤立簇上的玻尔兹曼平均与插值一致。先验的。