Sites on the Coarse-Grained Scale

In a meso-scale model, a group of atoms is often replaced by a single interaction center. This center is usually the size of a monomer in a polymer and it is often called a super-atom. Because the super-atoms are the only interaction centers in a meso-scale simulation, they are required to carry the information of the interactions between the real atoms in their local geometrical arrangements that are imposed by the chemistry of the polymer. 

Coarse-graining techniques are based on the idea of effective interaction potentials between super-atoms. The larger-scale model is calibrated against the smaller-scale model, which is considered to be more reliable and is used as a gold standard. Thus, any deficiencies of the small-scale model are carried over to the large-scale model. 

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