SI file

Active space orbitals, examples of the employed OpenMolcas inputs, CASSCF(18,14) natural occupation numbers at the S1 minima for both the S0 and S1 states, CASSCF(14,11) and XMS-CASPT2(14,11) optimized S1 minima and S1/S0 MECIs, orbitals describing the S1-1(nAπ*) and T2-3(πOπ*) states, CASSCF(14,11) natural bond orders for the NO bonds at the optimized geometries for the S1 state, and Cartesian coordinates of all optimized geometries.