Photoelectron spectroscopy of palladium-doped gold cluster anions; AunPd− (n=1–4)

Palladium-doped gold clusters, AunPd− (n=1–4), were investigated using anion photoelectron spectroscopy at 4.66 eV photon energy. Electron affinities (EAs) and vertical detachment energies (VDEs) are determined, and the electronic structures of Pd-doped Aun clusters are compared to those of pure Aun clusters. A peak shape analysis reveals electronic and geometric similarity between Aun− and Aun−1Pd− clusters and it is found that (1) an electron promotion occurs from 4d to 5s orbital in the Pd atom, and that (2) the bond of Au–Pd is formed through σ orbital between 6s of Au and 5s of Pd.