Here, a is a scaling factor that is chosen to be a = 1 2 unless otherwise mentioned. We will go through the three model systems shown in Figure 1. Conjugated system in the form of a polyene (1) where the current runs primarily through the π-system. As all carbons are sp 2 -hybridized, it is similar to the graphene systems previously investigated. 2. Alkane, in the form of heptane (2), where the current density curves away from the bonds instead of following them.