Effect of the interface structure on the high-temperature morphology of supported metal clusters

The morphology of Pd clusters prepared by ultrahigh-vacuum condensation or wet impregnation on MgO and the structure of the interfaces are studied by weak-beam dark-field and high-resolution electron microscopy, according to the particie sizes. The shapes are stable when the particles are annealed at increasing temperature, they are close to the eauilibrium forms. Their adhesion energy β with the substrate is experimentally deduced from the Wulff-Kaishew construction. It decreases when the particie size increases, and with the formation of defects at the interface.