Coarse-graining (CG) is a systematic reduction of the number of degrees offreedom (DOF) used to describe a system of interest. CG can be thought of as aprojection on coarse-grained DOF and is therefore dependent on the functionsused to represent the CG force field. In this work, we show that naiveextensions of the coarse-grained force-field can result in unphysicalparametrizations of the CG potential energy surface (PES). This issue can beelevated by coarse-graining the two- and three-body forces separately, whichalso helps to evaluate the importance of many-body interactions for a givensystem. The approach is illustrated on liquid water, where three-bodyinteractions are essential to reproduce the structural properties, and liquidmethanol, where two-body interactions are sufficient to reproduce the mainfeatures of the atomistic system.
展开▼
