Bomont Jean-Marc, Costa Dino, Bretonnet Jean-Louis
Université de Lorraine, LCP-A2MC EA 3469, 1 Bd. F. Arago, Metz, France.
Phys Chem Chem Phys. 2017 Jun 14;19(23):15247-15255. doi: 10.1039/c7cp01811h.
We use Monte Carlo simulations to carry out a thorough analysis of structural correlations arising in a relatively dense fluid of rigid spherical particles with prototype competing interactions (short-range attractive and long-range repulsive two-Yukawa model). As the attraction strength increases, we show that the local density of the fluid displays a tiny reversal of trend within specific ranges of interparticle distances, whereupon it decreases first and increases afterwards, passing through a local minimum. Particles involved in this trend display, accordingly, distinct behaviours: for a sufficiently weak attraction, they seem to contribute to the long-wave oscillations typically heralding the formation of patterns in such fluids; for a stronger attraction, after the reversal of the local density has occurred, they form an outer shell of neighbours stabilizing the existing aggregation seeds. Following the increment of attraction, precisely in correspondence of the local density reversal, the local peak developed in the structure factor at small wavevectors markedly rises, signalling-in agreement with recent structural criteria-the onset of a clustered state. A detailed cluster analysis of microscopic configurations fully validates this picture.
我们使用蒙特卡罗模拟对具有原型竞争相互作用（短程吸引和长程排斥双 Yukawa 模型）的相对致密的刚性球形颗粒流体中产生的结构相关性进行全面分析。随着吸引强度的增加，我们表明流体的局部密度在特定的粒子间距离范围内显示出微小的趋势反转，即先减小后增加，经过一个局部最小值。相应地，参与这种趋势的粒子表现出不同的行为：对于足够弱的吸引力，它们似乎有助于长波振荡，这通常预示着此类流体中模式的形成；对于更强的吸引力，在局部密度发生反转之后，它们形成一层邻居外壳，稳定现有的聚集种子。随着吸引力的增加，恰好与局部密度反转相对应，在小波矢处结构因子中出现的局部峰值显著上升，这与最近的结构标准一致，表明聚集态的开始。对微观构型的详细聚类分析充分验证了这一图景。
