Notebook 2 has students select a PAH ranging in size from naphthalene (2 rings) to heptacene (7 rings) and perform a quick force-field optimization followed by a HF calculation with an STO-3G basis set from an electronic structure package available in Python, PySCF. The frontier orbitals can then be rendered with py3Dmol. These tend to have the appearance of familiar linear combinations of carbon p orbitals. At this point interesting comparisons with the results from Notebook 1 can be made, specifically relating to the nodal structure of the orbitals. In the case of anthracene, the HOMO-3 consists of two lobes along the 'x' axis (Figure ), which closely resembles the 121 state from the anthracene-shaped box in Figure . If the orthogonal nodal plane containing the nuclei is ignored, the 321 PIB state (Figure ) also has the same general shape as the HOMO from the HF calculation (Figure ), so the orbitals between the approaches have a nice correspondence despite arising from very distinct Hamiltonians. While the absolute energies between the two models is large (in fact the PIB has no bound states), the qualitative trend of decreasing HOMO-LUMO gap with increasing PAH length can be observed in the first notebook by constructing boxes of increasing size and affirmed in the second.