Joint experimental and theoretical investigations of the reactivity of Au2On- and Au3On- (n=1-5) with carbon monoxide

The interactions between small gold oxide cluster anions, Au2,3On- (n=1-5), and CO were investigated in a fast-flow reactor mass spectrometer, and experimental results were verified with a guided ion beam mass spectrometer. Density functional calculations along with molecular dynamics simulations were also utilized to explain the experimental findings. From these studies, we show that, for the interactions between AumOn- and CO, each atom counts. With the addition of a single gold atom, it is observed that association of CO and replacement of O-2 by CO become the dominant reaction channels as opposed to CO oxidation. We also present results that show that the oxidation of CO takes place only in the presence of a peripheral oxygen atom. However, this condition is not always sufficient. Furthermore, the association of CO onto AumOn- follows a general qualitative rule based on the relationship between the energy of the cluster lowest unoccupied molecular orbital and the binding energy of CO. (c) 2006 American Institute of Physics.