Tools for Understanding Molecular Orbital Interactions of Molecules on Surfaces─Density Functional Theory Calculations of H ₂ Adsorbed on Cu(111) and Pd/Cu(111)

We provide a summary of contemporary computational tools utilized in the study of adsorbate interactions with solid-state materials from the perspective of a quantum chemist. This work contains a focused theoretical primer of interactions between the molecular orbitals of an adsorbate and the electronic bands of a solid as well as a review of the promising methodologies for disentangling these contributions. We apply these tools in a methodological fashion to density functional theory (DFT) calculations of molecular hydrogen (H2), H2 adsorbed to the pristine Cu(111) surface, and H2 adsorbed to a single-atom alloy composed of palladium and copper (Pd/Cu(111)) to provide chemically intuitive explanations of bonding in these systems.