Abstract

The adsorption of pairwise interacting particles on fractal surfaces has been studied by grand canonical Monte Carlo simulations. The substrate is built from a mixture of two types of objects: (i) objects with two bonds and (ii) objects with four bonds. These objects move on a square lattice, according to diffusion-limited aggregation (DLA) rules, and stick to each other only if they have a free bond pointing at each other and, of course, are first neighbors of each other. The resulting substrate, which is named as bivariate diffusion-limited aggregate (BDLA), is a fractal structure composed by two bonds units with fraction \(f_2\) and four bonds units with concentration \(f_4=1-f_2\). Different surface morphologies are obtained by varying \(f_2\) and \(f_4\). In the limit case of \(f_2=0\) and \(f_4=1\), the standard DLA model is recovered. In addition, repulsive lateral interactions between adsorbed particles are considered. Adsorption isotherms and differential heats of adsorption are calculated for different values of the parameters of the system. In the case of high repulsive couplings, a wide variety of structural orderings are observed in the adlayer. The main characteristics of these ordered phases are discussed in terms of the topological properties of the bivariate aggregates.

Graphic abstract

中文翻译：

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相互作用颗粒在双变量扩散受限聚集体上的吸附

摘要

分形表面上成对相互作用粒子的吸附已通过经典的蒙特卡洛模拟研究。基材由两种类型的物体的混合物构成：（i）具有两个键的物体和（ii）具有四个键的物体。这些对象根据扩散限制聚合（DLA）规则在正方形晶格上移动，并且仅在它们具有指向彼此的自由键并且当然是彼此的第一近邻时才彼此粘附。所得的底物称为二元扩散限制聚集体（BDLA），它是由分数为（f_2 \）的两个键单元和浓度为（（f_4 = 1-f_2 \）的四个键单元组成的分形结构。通过改变\（f_2 \）和\（f_4 \）。在\（f_2 = 0 \）和\（f_4 = 1 \）的极限情况下，将恢复标准DLA模型。另外，考虑了吸附颗粒之间的排斥性横向相互作用。针对系统参数的不同值，计算了吸附等温线和吸附热差。在高斥力耦合的情况下，在吸附层中观察到各种各样的结构顺序。这些有序相的主要特征是根据二元聚集体的拓扑性质进行讨论的。

图形摘要