Homologous series of molecules. As previously elaborated, HOMO-LUMO gap and polarizability can seemingly correlate for molecules that belong to a homologous series. This can be explained by the fact that the electronic nature and order of the frontier orbitals is often identical for structurally and electronically similar molecules. Consequently, the decrease in the HOMO-LUMO gap can correlate with the increase in polarizability when considering molecules of a homologous series with an increasing number of repeating units. To support this assumption, we consider in the following a series of oligomers, namely alkanes (C m H 2m+2 ) and alkenes (C m H 2m ; see Fig. ). The example is taken from Afzal et al. , with polarizability and HOMO-LUMO gap recalculated within our computational setup (cf. Sec. 6).