Structural Origin of Spin‐Orbit Splitting of 1P Orbitals of Icosahedral Au ₁₃ Superatom Protected by Ligands

Abstract The key structural factors underlying the spin‐orbit (SO) splitting of the 1P orbitals in thiolate‐protected Au 13 superatoms were investigated using cryogenic anion photoelectron spectroscopy (PES) and two‐component density functional theory (2c‐DFT) calculations. PES revealed that the 1P orbitals of the Au 13 and Au@Ag 12 superatomic cores undergo splitting, whereas those of the Ag 13 core do not. According to 2c‐DFT calculations, the SO splitting of the 1P orbitals of the Au 13 superatom stems from the symmetry‐dictated coupling between the 6p orbitals of the central Au atom and the 1P orbitals formed by the surrounding icosahedral Au 12 shell, both of which are split by SO effects.