PNNL

Abstract

Structure isomers of the Au10- cluster and their chemical reactivity with O2 are studied using photoelectron spectroscopy under different experimental conditions. In addition to the global minimum triangular D3h structure, at least three low-lying isomers (X', X'', and X''') are observed distinctly using argon tagging and O2 titration. The D3h structure has a very high electron affinity of 3.88 eV, whereas the low-lying isomers have lower electron affinities (2.86, 3.09, and 3.45 eV for X', X'', and X''', respectively). It is found that the D3h global minimum does not react with O2 and can only form a physisorbed Au10(O2)* van der Waals complex under cold experimental conditions. The three low-lying isomers are reactive with O2 and can be systematically titrated out of the cluster beam using an O2-seeded carrier gas, leaving a clean D3h Au10 - beam.