Parallel molecular dynamics simulations for the oxidation of an aluminium nanocluster

The oxidation of an Al nanocluster with radius 100 Angstrom placed in oxyge n gas at room temperature is investigated by performing molecular dynamics simulations on parallel computers. The simulations take into account the ef fects of dynamic charge transfer between Al and O on the basis of electrone gativity-equalization principles. We thereby fmd that molten surface oxides are saturated to depths of 28-33 Angstrom; this saturation is accompanied by depletion of oxygen near the cluster in the environment Upon quenching t he cluster further in oxygen gas, amorphous surface oxides with depths simi lar to 38 Angstrom are formed. The microscopic structures of the amorphous oxides are characterized.