3.2. Two-Dimensional Energy Profiles. In order to gain more insight about the role of the vdW contribution to the interaction energy, we next examine two-dimensional potentials representing potential scans at fixed face-to-face separation. (These scans represent rigid translations of fixed monomer geometries, with fixed orientation as well.) Only the vdW interaction energy (E vdW ) is considered in detail due to its qualitative resemblance to E int that was documented above, although two-dimensional scans for some other energy components can be found in Figs. S7-S10.