Formation of cationic gold clusters on the MgO surface from Au(CH3)(2)(acac) organometallic precursors: A theoretical analysis

The formation of gold atoms and clusters from the reduction by hydrogen of mononuclear [Au(CH3)(2)(acac)] organometallic complexes deposited on the MgO surface has been studied by first principle density functional theory calculations. The comparison of measured and computed infrared data suggests the occurrence of a dissociative adsorption of the complex on the surface of the oxide, although a given fraction of undissociated molecules can cohexist. The reduction can follow various mechanisms, leading to the formation of neutral or positively charged mononuclear gold intermediates. We show that some of these intermediates can easily diffuse on the surface at room temperature and lead to nucleation of stable partially oxidized gold clusters