This talk demonstrates the utility of the new generations of coupled-cluster methods and algorithms, including the completely renormalized CR-CC(2,3) approach and the parallel numerical derivatives combined with a parallel implementation of CCSD(T), in obtaining definitive answers regarding catalytic and structural properties of gold nanoparticles. It is, in particular, demonstrated that the CR-CC(2,3) approach applied to methanol oxidation to formic acid on Au8- cluster,  which is a model for aerobic oxidations on gold nanoparticles, supports the previously postulated exothermic reaction mechanism, placing the initial rate-determining transition state, which corresponds to hydrogen transfer from the methoxy species to O2, at about 20 kcal/mol above the reactants, less than 40 kcal/mol above the co-adsorbed O2 and CH3O- species, and considerably above the remaining two transition states along the reaction pathway. Our unprecedented CR-CC(2,3) calculations enable us to obtain useful lessons for methods based on density functional theory, which are often used in similar applications and provide uncertain information. We also show that the definitive large-scale CCSD(T) calculations employing the CCSD(T)-optimized geometries and correlating the valence and semi-core electrons favor the planar configuration of the Au8 particle, which was the subject of controversies in the past, with the next three non-planar structures separated by 4-6 kcal/mol.

Utility of new generations of coupled-cluster methods and algorithms in catalytic and structural properties of gold nanoparticles

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.