The top ten most common monomers from Figure have small HOMO-LUMO gaps and small ∆E T -S , as well as relatively low LUMO levels while their relative HOMO levels are more spread out (Table ). However, these monomers are not all in the extreme ends of any category, and there are other monomers with small HOMO-LUMO gaps, for example, that did not show up as common in the GA as those top ten monomers. We can attribute this to several potential causes: • Due to random chance in the GA. The GA is a stochastic optimization method, and by chance some potentially good monomers were not selected.