Fig. 3
From: An isolable catenane consisting of two Möbius conjugated nanohoops

Gradient isosurface colored according to values of sign(λ2)ρ of the energy minimized structure of catenane 1. An isovalue of 0.7 a.u. is applied. The color scale ranges from −0.04 (blue) to 0.02 (red) a.u. Large, negative values of sign(λ2)ρ indicate attractive interaction. Large, positive values reflect strong non-bonded overlapping which is generally resulted from steric repulsion. Values near zero correspond to the magnitude of van der Waals interaction