Figure : Minimum-energy crossing points (MECPs) along two different S0/S1 conical seams for the ethylene molecule, plotted as a function of orthogonalized g and h coordinates. These calculations were performed using SF-TDDFT and the resulting potential surfaces exhibit the correct double-cone topology of a CX. The intersection in (a) is strongly peaked whereas the one in (b) is more sloped. Energy is measured relative to the minimum-energy S0 geometry. Reprinted from Ref. 6; copyright 2016 American Chemical Society.