Single reference methods. We used density functional theory (DFT) to optimize the groundstate global minima of 1, 2, and 3. Geometries were optimized using the PBE0-D3BJ/cc-pvdz . Time-dependent density functional theory (TDDFT) was used to calculate the excitation energies and wavelengths for the first 10 excited states of 1, 2, and 3. The TD-DFT calculations were run using the CAM-B3LYP functional with the aug-cc-pVTZ basis set. Since DFT is a singlereference method, it cannot accurately predict the electronic structure of regions on a PES where there is substantial coupling between two electronic states, such as crossing seams and conical intersections. Because of this, we used multiconfigurational methods to more accurately predict the topology of the PES near these crossing regions.