Using the relaxed 𝐶 2h geometry leads to dramatic changes in the frontier orbitals, with an increased HOMO-LUMO overlap of 0.86 and a sizeable exchange interaction of 0.689 eV (Figure ). Consequently, the calculated gap is now normal at Δ𝐸 DSP ST,SCF = 0.570 eV, aggravated by a diminished Δ𝐸 DSP SCF of only -0.118 eV. A similar result is obtained with CIS: Δ𝐸 DSP ST,CIS = 0.914 eV. The reference value calculated with ADC(2) is 0.864 eV. The excitations contributing to Δ𝐸 DSP SCF at the 𝐷 2h geometry have been significantly diminished, only partially alleviated by the addition of a minor stabilization from HOMO-2 → LUMO+3 (2 → 8 in Figure ). Azaphenalene is the prototypical molecule that started the renewed investigations into INVEST molecules, and has been the subject of numerous studies with high-level quantum chemical methods. Can we capture the inverted gap, as first measured by Leupin and Wirz in 1980? The calculations reveal that the HOMO and LUMO are well separated with spatial overlap of 0.14 and a correspondingly low exchange interaction of only 0.028 eV (Figure ). The larger azaphenalene has 30 excitations that could possibly contribute to the large Δ𝐸 DSP SCF of -0.492 eV, but the most important by far are those from the doubly degenerate HOMO-1 to the doubly degenerate LUMO+1 (5 → 10 and 6 → 9 in Figure ). In total, Δ𝐸 DSP ST,SCF = -0.464 eV, which is slightly smaller at the CIS level with Δ𝐸 DSP ST,CIS = -0.321 eV. To conclude this section on the model compounds, our PPP-based protocol is able to capture the inverted gap, and also provides qualitative understanding into the physical mechanism of dynamic spin polarization through identification and visualization of the corresponding excitations. For these two compounds, the calculated Δ𝐸 DSP ST, are more negative at the SCF level compared to CIS. Compared to ADC(2), it would seem that CIS is preferable, but to elucidate which method is better, we now turn to larger datasets.