The S 1 and T 1 surfaces are similar for the three LIIC surfaces, where the T 1 state is slightly higher than the S 1 , but separated by less than 2 kcal/mol across the surface. We note in passing that the XMS-CASPT2 energy on the TPSSh geometry is 0.5 kcal/mol lower than on the XMS-CASPT2 structure, but caution readers from reading anything into this since the optimization was performed on a smaller active space. Although an LIIC is one way to explore a slice of the PES, one could also following a particular geometric parameter. Prior work by Pierloot et al. reported the SS-CASPT2(12e,13o) surface along the dihedral angle Ω between the saddled and planar structures. Although the intermediate points differ, the starting and final structures are similar enough that one can compare the results. Both SS-CASPT2(12e,13o) and XMS-CASPT2(14e,15o) result in singlet ground states with similar percent radical character in the saddled geometry. However, the most prominent difference with SS-CASPT2(12e,13o) is that a singlet ground state dominated by the closed shell singlet HF determinant was obtained for the planar geometry. The saddled geometry was ∼5 kcal/mol higher, while the opposite trend between the two geometries was obtained in XMS-CASPT2(14e,15o). The SS-CASPT2(12e,13o) surface also includes a crossing between the S 0 and S 1 states. The results with the larger XMS-CASPT2(14e,15o) and comparisons with the larger RASSCF spaces suggest that the differences observed between the LIIC surfaces herein and the SS-CASPT2(12e,13o) surface are most likely due to differences in active space choice.