Cruz S M A, Marques J M C
Departamento de Química, Universidade de Coimbra , 3004-535 Coimbra, Portugal.
J Phys Chem B. 2016 Apr 7;120(13):3455-66. doi: 10.1021/acs.jpcb.6b01233. Epub 2016 Mar 28.
The target of this investigation is the systematic characterization of the low-energy structures of charged colloidal clusters that may be important to understand the self-assembling process of biomolecules. The aggregation of charged colloidal particles is governed by the attractive short-ranged Morse potential and the Yukawa repulsive tail to describe the long-range charge effect. A global optimization strategy, based on our own evolutionary algorithm, was adopted to discover the low-energy structures of colloidal clusters composed of up to 20 particles. A detailed analysis of the low-energy structures involving charged particles shows that the appearance of the Bernal spiral as the most stable motif occurs, first, at N = 6, but it is favored for larger clusters (N ≥ 13); for 6 ≤ N ≤ 12, there is a competition between the spiral (which is favored for higher charges) and more spherical-like structures. Finally, we study binary clusters composed by two sets of differently charged colloidal particles. Although a great diversity of low-energy structures is observed (especially for aggregates with one of the components in excess), the global minimum is disputed by three structural motifs depending on the composition of the cluster and, in some cases, on the range of the Morse potential.
本研究的目标是对带电胶体团簇的低能结构进行系统表征，这对于理解生物分子的自组装过程可能具有重要意义。带电胶体颗粒的聚集受吸引性短程莫尔斯势和描述长程电荷效应的汤川排斥尾的支配。我们采用基于自身进化算法的全局优化策略，来发现由多达20个粒子组成的胶体团簇的低能结构。对涉及带电粒子的低能结构的详细分析表明，作为最稳定 motif 的伯纳尔螺旋首先在 N = 6 时出现，但对于更大的团簇（N ≥ 13）更受青睐；对于 6 ≤ N ≤ 12，螺旋结构（在较高电荷时更受青睐）和更类似球形的结构之间存在竞争。最后，我们研究了由两组不同电荷的胶体粒子组成的二元团簇。尽管观察到了多种多样的低能结构（特别是对于其中一种组分过量的聚集体），但全局最小值取决于团簇的组成，在某些情况下还取决于莫尔斯势的范围，由三种结构 motif 竞争确定。
