Low-energy-deposited Au clusters investigated by high-resolution electron microscopy and molecular dynamics simulations

We investigated the cluster-surface interaction of Au clusters deposited on MgO cubes and on amorphous carbon, and its influence on the morphology of the Au cluster. Au clusters, produced in a laser vaporization source, are d eposited with low energy on carbon-coated microscope grids on which MgO cub es are first deposited as substrates. Clusters on the amorphous carbon as w ell as clusters on the MgO cubes are studied by high-resolution electron mi croscopy (HREM). The clusters have different morphologies for the two diffe rent surfaces, and a dilation of the Au lattice is also measured for the cl usters deposited on the crystalline surface of MgO to perfectly accommodate the MgO lattice. Classical molecular dynamics (MD) is applied to model thi s behavior. Good agreement is found between experimental cross-section HREM images and theoretical images simulated with the multislice technique usin g the model calculated by MD.