FIGURE 6 is near here
Figure 6 presents the regions of electronic concentration and depletion
along each bond in the six dimers; both the contour maps (left) and
relief maps (right) of ∇2ρ (b) are shown. The
blue points denote BCPs. The blue lines denote positive Laplacian of
electron density, which indicate interactions of an ionic character
(e.g. van der Waals or intermolecular interactions), and the red lines
denote negative Laplacian of electron density which indicate covalent
bonds. The corresponding values of the Laplacian of electron density are
listed in Table 6. Relief maps provide an intuitive view of the
Laplacian of electron density, the curves above the plane show the
positive Laplacian of electron density, and the curves below the plane
show the negative Laplacian of electron density.