The role of adatoms in the adsorption of conjugated aromatic molecules onto metallic substrates has been investigated in other works. Bartels et al. reported that adatoms diffuse on the substrate at temperatures as low as 200 K, highlighting the likelihood of adatoms being present on substrates, particularly on soft metals such as copper. Their work suggests that adatoms become coordination sites, with up to four small ligands binding to one adatom. The coordination geometry generally reflects the symmetry of the underlying metal lattice: three-fold ligand symmetry for fcc (111) substrates, two-or four-fold symmetry for fcc(100) substrates. The nature of coordination bonds formed on metallic substrates is less well understood than in solution phase, where the formal oxidation state of the metal adatoms can usually be clearly defined. On metals, the steric bulk and electronic density of the surface affect adsorbate geometries and charge distributions. The metal substrate acts as an electron reservoir, allowing substrate coordination centers to donate, or potentially accept, charge without becoming charged themselves. Furthermore, metal adatoms situated atop bare metal substrates rest approximately 10% closer to the substrate than the substrate layer spacing, allowing the adatoms' charge density to spread out into the substrate, and leading to polarization of the adatom site. Modelling these fundamentally quantum effects requires the use of quantum chemical techniques, such as DFT, and large simulation sizes.