Figure 1.

Plot of relative differences between the approximate and canonical interaction energies, which are described in the text, for structures of ten pi-stacked dimers from the S66x8 set [25] in geometries defined by the scaled distance between monomers. Data points are color-coded with the benzene dimer in red, pyridine dimer in green, uracil dimer in orange, benzene–pyridine in cyan, benzene–uracil in magenta, pyridine–uracil in brown, benzene–ethene in black, uracil–ethene in teal, uracil–ethyne in yellow and pyridine–ethene in blue color.