Larger values of s x or s y indicating sloped rather than peaked character along the direction of corresponding branching-plane vector (g IJ or h IJ , respectively). If s x = s y = ∆ gh = 0, the CX is vertical and cylindrically symmetric. Topographical parameters for the MECP(C 2 C 3 ) point of C 5 H 6 NH + 2 are listed in Table . The two LR-TDDFT methods predict much larger values of d gh as compared to either SF-BH&HLYP or CASSCF, indicating a much more sharply peaked topography near the CX. Meanwhile, ∆ gh ≈ 1 for the LR-TDDFT methods, indicating that the CX is strongly asymmetric. Along with the very large values of s y /h, this indicates significant slope along the h direction, which is a direct consequence of nearly vanishing coupling between S 0 and S 1 in LR-TDDFT. The same conclusion can be reached by examining the g and h vectors, which are plotted for MECP(C 2 C 3 ) in Fig. . To have a point of comparison at the LR-ωB97X level, where the appearance of triplet instabilities precludes a full optimization of the MECP, we started in that case from the MECP(C 2 C 3 ) structure located using LR-ωB97X/TDA and minimized along the energy gap until an instabil- ity appeared. The resulting structure has an energy gap < 0.01 eV and is likely very close to a MECP structure.