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 deposited with low energy on carbon-coated microscope grids on which MgO cubes are first deposited as substrates. Clusters on the amorphous carbon as well as clusters on the MgO cubes are studied by high-resolution electron microscopy (HREM). The clusters have different morphologies for the two different surfaces, and a dilation of the Au lattice is also measured for the clusters deposited on the crystalline surface of MgO to perfectly accommodate the MgO lattice. Classical molecular dynamics (MD) is applied to model this behavior. Good agreement is found between experimental cross-section HREM images and theoretical images simulated with the multislice technique using the model calculated by MD.