Journal of Physical Chemistry A, Vol.115, No.14, 3006-3015, 2011
Gas-Phase Experiments on Au(III) Photochemistry
Irradiation of AuCl4- and AuCl2(OH)(2)(-) in the gas-phase using ultraviolet light (220-415 nm) leads to their dissociation. Observed fragment ions for AuCl4- are AuCl3- and AuCl2- and for AuCl2(OH)(2)(-) are AuCl2- and AuClOH-. All fragment channels correspond to photoreduction of the gold atom to either Au-(II) or Au-(I) depending on the number of neutral ligands lost. Fragment branching ratios of AuCl4- are observed to be highly energy dependent and can be explained by comparison of the experimental data to calculated threshold energies obtained using density functional theory. The main observed spectral features are attributed to ligand-to-metal charge transfer transitions. These results are discussed in the context of the molecular-level mechanisms of Au-(III) photochemistry.