To focus on non-covalent interactions, charge density cutoffs exclude covalent bonds and regions near nuclei, typically using ρ c = 0.05 a.u. . NCI isosurfaces are defined over an s iso range, usually 0.2 -0.7, with the specific value chosen to match NCI signatures from the 2D plots (see Figure ). An example NCI isosurface for the 7b host-guest complex, using s iso = 0.5, is displayed in the inset, demonstrating the correspondence between the s(ρ) diagram and the 3D NCI isosurface.