Departamento de Física and IUdEA, Universidad de La Laguna, 38205, La Laguna, Tenerife, Spain.
Phys Chem Chem Phys. 2019 Feb 27;21(9):5123-5132. doi: 10.1039/c8cp07724j.
The aggregation and physical growth of polycyclic aromatic hydrocarbon (PAH) molecules was simulated using a coarse-grained (CG) approach based on the Paramonov-Yaliraki (PY) potential and a stochastic Monte Carlo framework, following earlier efforts in which the structure [Phys. Chem. Chem. Phys., 2016, 18, 13736] and equilibrium thermodynamics [Phys. Chem. Chem. Phys., 2017, 19, 1884] were investigated and critically compared to the predictions of all-atom models. Homomolecular and heteromolecular assemblies of pyrene, coronene, and circumcoronene were considered at various temperatures and compositions, and the distributions of aggregation products were characterized. Under the simulated conditions, and in agreement with earlier studies, the clusters are rather small and, in the case of pyrene-rich systems, only formed below 1000 K. The clusters obtained by spontaneous aggregation of isolated molecules are statistically analysed. For the selected sizes of tetramers and octamers, broad distributions of isomers are obtained with a clear entropic stabilization. In heteronuclear assemblies, our results suggest a minor spontaneous segregation towards pure and equi concentrations at variance with purely statistical expectations.
采用基于 Paramonov-Yaliraki (PY) 势能和随机蒙特卡罗框架的粗粒化 (CG) 方法模拟多环芳烃 (PAH) 分子的聚集和物理生长，这是在之前的研究工作基础上进行的，其中结构 [Phys. Chem. Chem. Phys., 2016, 18, 13736] 和平衡热力学 [Phys. Chem. Chem. Phys., 2017, 19, 1884] 进行了研究，并与全原子模型的预测进行了批判性比较。在不同的温度和组成下，考虑了并五苯、蒄和围冠烯的同分子和异分子组装体，并对聚集产物的分布进行了表征。在模拟条件下，与早期研究一致，簇相当小，并且在富含并五苯的体系中，仅在 1000 K 以下形成。对孤立分子自发聚集得到的团簇进行了统计分析。对于选择的四聚体和八聚体的大小，得到了具有明显熵稳定化的异构体的宽分布。在异核组装体中，我们的结果表明，与纯粹的统计预期相反，存在向纯和等浓度自发分离的趋势。
