Based on the trends in bond lengths and charges, we conclude that the best explanation for the control of the HOMO and LUMO energies afforded by ligand substitution in these clusters is resonance effects, and that the traverses the Au-P bonds to include the cluster core. This is perhaps somewhat surprising because, while the HOMO and LUMO of Au 8 (PPh 3 ) 2+ and Au 9 (PPh 3 ) 3+ 8 are superatomic orbitals delocalized across the cluster core, this result suggests that there is still some clear contribution to those orbitals from Au-ligand bonding that should be able to be rationalized in a manner similar to that of a mononu- clusters with respect to the Hammett meta-parameter (σ m ). In both cases, quantities are averaged over all chemically equivalent bonds/atoms in the Au 8 (PPh 3 ) 2+ 7 system. At the top is an explanation of the color coding of the figures along with the expected trends as the para-substituent changes from H to Me to OMe, assuming resonance is the dominant effect. C i is the ipso carbon with respect to the P atom, C o is the ortho carbon, C m is the meta carbon, and C p is the para carbon. clear coordination complex. We consider two possibilities: that there is a relatively local bonding orbital at the Au-P interface that mixes with the cluster core-based HOMO and/or LUMO superatomic orbitals, or that the HOMO and/or LUMO superatomic orbitals are more extensively delocalized onto the ligands. The fact that the ground state bond lengths and charges show evidence of resonance effects indicates that one of these cases must hold for the HOMO. However, it is unclear if either applies to the LUMO. substituted with OMe in the para-and meta-positions, as determined for an isosurface value of 0.005. Contributions from oxygen atomic orbitals are highlighted by *. (bottom) Images focusing on example oxygen orbital shapes for these orbitals, noted with , that demonstrate the out of plane nature of the oxygen p orbital in the para-case and the in plane nature in the meta-case. These orbitals were computed via natural transition orbital analysis. To determine the degree of delocalization, we performed time-dependent density functional theory calculations of the HOMO-LUMO transition. Indeed, extensive delocalization is observed. Figure presents the HOMO for para-and meta-OMe-substituted Au 8 (PPh 3 ) 2+ 7 ,