Ab initio and anion photoelectron study of AunRhm (n = 1–7, m = 1–2) clusters

Abstract

Anion photoelectron spectroscopy (PES) and ab initio calculations have been used to identify the unique structural, electronic, and magnetic properties of both neutral and anionic binary Au_nRh_m (n = 1–7 and m = 1–2) clusters in vacuo. Negative ion photoelectron spectra are presented with electron binding energies measured up to 3.493 eV. We discuss our computational results in the context of the PES experiment, in which the calculated electron affinities and vertical detachment energies are in good agreement with the measured values. Theoretically, we investigate the low-lying energy structures and the spin isomers of each neutral, anionic and cationic species. The PES spectra, binding energies, fragmentation energy, electron affinities, vertical and adiabatic detached energies, HOMO–LUMO (H–L) gaps and vibrational spectra are presented and discussed. Our results show that the characteristic planarity for gold clusters is preserved for many of the bimetallic clusters. This study is therefore compared with the case of pure gold for which ample experimental and theoretical data are available. Both experimental and theoretical results obtained here are compared and discussed with previous theoretical studies on the same systems.