From the schematic diagram [Fig. ], it is clear that the MECP is ∼ 0.6 eV lower in energy than FC. But this does not necessarily imply that the deactivation pathway of Ds will be barrier-less. Therefore, the question comes in mind that is there any barrier along the pathway from FC to MECP? To answer this question, LIIC-PES has been created connecting FC to MECP. The LIIC-PES has very high barrier which is expected as the MECP is highly non-planar and there are lots of mixing of orbitals involved in the lower-lying excited states.