Invernizzi Michele, Valsson Omar, Parrinello Michele
Department of Physics, Eidgenössische Technische Hochschule (ETH) Zurich c/o Università della Svizzera Italiana (USI) Campus, 6900 Lugano, Switzerland.
Facoltà di Informatica, Instituto di Scienze Computationali, and National Center for Computational Design and Discovery of Novel Materials MARVEL, Università della Svizzera Italiana, 6900 Lugano, Switzerland.
Proc Natl Acad Sci U S A. 2017 Mar 28;114(13):3370-3374. doi: 10.1073/pnas.1618455114. Epub 2017 Mar 14.
A powerful way to deal with a complex system is to build a coarse-grained model capable of catching its main physical features, while being computationally affordable. Inevitably, such coarse-grained models introduce a set of phenomenological parameters, which are often not easily deducible from the underlying atomistic system. We present a unique approach to the calculation of these parameters, based on the recently introduced variationally enhanced sampling method. It allows us to obtain the parameters from atomistic simulations, providing thus a direct connection between the microscopic and the mesoscopic scale. The coarse-grained model we consider is that of Ginzburg-Landau, valid around a second-order critical point. In particular, we use it to describe a Lennard-Jones fluid in the region close to the liquid-vapor critical point. The procedure is general and can be adapted to other coarse-grained models.
处理复杂系统的一种有效方法是构建一个粗粒度模型，该模型能够捕捉其主要物理特征，同时在计算上是可行的。不可避免地，这种粗粒度模型会引入一组唯象参数，这些参数通常不容易从底层的原子系统中推导出来。我们基于最近引入的变分增强采样方法，提出了一种计算这些参数的独特方法。它使我们能够从原子模拟中获得这些参数，从而在微观和介观尺度之间建立直接联系。我们考虑的粗粒度模型是金兹堡-朗道模型，在二阶临界点附近有效。特别是，我们用它来描述接近液-气临界点区域的 Lennard-Jones 流体。该过程具有通用性，可适用于其他粗粒度模型。
