Figure 1.

Cartoon explaining different truncation schemes of the electrostatic interactions. In the group-based scheme, (a), the interactions between two molecules are zero unless the distance between the “centers” of these molecules is below R_c. Several definitions of the centers can be used. In (a), molecule A interacts with molecule B but not with molecule C. In the atom-based truncation, (b), only the pairs of atoms with separation r≤R_c are considered. In (b), oxygen of molecule A interacts with hydrogens of molecule B but not its oxygen.