Dipartimento di Fisica "A. Pontremoli", Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy.
Soft Matter. 2018 Aug 21;14(31):6595-6612. doi: 10.1039/c8sm01124a. Epub 2018 Jul 27.
The formation of mesophases in fluids with hard-core plus tail interactions is investigated and compared with the occurrence of cluster crystals in ultra-soft repulsive potentials by using a simple variational expression for the Helmholtz free energy. The purpose of this study is mostly qualitative, i.e., to explain the origin of the different behavior of these systems, and the reason why, in the hard-core case, interactions which are apparently quite different display a common pattern for the phase diagram, featuring spheres, cylinders, lamellae, inverted cylinders, and inverted spheres as the density is increased. In the limit of zero temperature, our approach also yields some simple predictions for the densities at which the transitions between different mesophases are expected to take place, as well as for the size of their clusters at the transitions. We find that these results compare favorably with those obtained in a former study of a model fluid with competing attractive and repulsive interactions by density-functional theory with numerical minimization.
本文通过使用简单的亥姆霍兹自由能变分表达式，研究了硬球加尾相互作用流体中中间相的形成，并将其与超软排斥势中团簇晶体的出现进行了比较。本研究主要是定性的，即解释这些系统不同行为的起源，以及为什么在硬球情况下，明显截然不同的相互作用显示出具有共同模式的相图，特征为密度增加时出现球体、圆柱、层状、倒圆柱和倒球体。在零温度极限下，我们的方法还对不同中间相之间的转变预计发生的密度以及转变时的团簇大小做出了一些简单的预测。我们发现，这些结果与通过密度泛函理论数值最小化对具有竞争吸引和排斥相互作用的模型流体进行的先前研究中得到的结果相当吻合。
