Extended ensemble approach for deriving transferable coarse-grained potentials

Coarse-grained (CG) models provide a computationally efficient means for investigating biological and soft-matter processes that evolve on long time scales and large length scales. The present work introduces an extended ensemble framework for calculating transferable CG potentials that accurately reproduce the structure of atomistic models for multiple systems. This framework identifies a generalized potential of mean force (PMF) as the appropriate CG potential for reproducing the structural correlations of an atomistic extended ensemble. A variational approach is developed for calculating transferable potentials that provide an optimal approximation to this PMF. Calculations for binary mixtures of alkanes and alcohols demonstrate that the extended ensemble potentials provide improved transferability relative to potentials calculated for a single system. (C) 2009 American Institute of Physics. [doi:10.1063/1.3220627]