Published online by Cambridge University Press: 15 February 2011
Three gold clusters, Au55 (PPh3 )12Cl6, Au55{PPh2(C6H4SO3Na)}12Cl6 and Au11{PPh2(p-ClC6H4)}7I3 (which we shall denote Au55, Au55, and Au11 for convenience) have been studied using EXAFS. Average near-neighbour bond lengths are contracted from the bulk by approximately 0.15Å (±0.02Å) for Au55, and 0.22Å (± 0.02Å) for Au11. Ligand contributions have been successfully modelled in the fitting. Debye-Waller factors for samples at room temperature and at 80K are compared to ascertain the relative degrees of thermal and static disorder present in the systems. Results clearly indicate that static structural disorder predominates over thermally induced vibrational disorder.