The role of many-body correlations in determining potentials for coarse-grained models of equilibrium structure

 

Coarse-grained (CG) models often employ pair potentials that are parametrized to reproduce radial distribution functions (rdf’s) determined for an atomistic model. This implies that the CG model must reproduce the corresponding atomistic mean forces. These mean forces include not only a direct contribution from the corresponding interaction but also correlated contributions from the surrounding environment. The many-body correlations that influence this second contribution present significant challenges for accurately reproducing atomistic distribution functions. In this paper, we present a detailed investigation of these many-body correlations and their significance for determining CG potentials while using liquid heptane as a model system.