RHEED investigation of lattice deformations of alpha-Al2O3 supported Pd particles

Pd particles were grown on (0001) and (2-1-10) surfaces of ct-alumina singl e crystals by means of molecular beam epitaxy. Particles exhibited (111) ep itaxy preferentially. The orientational relationship, as well as the precis e values of lattice parameter, were determined from RHEED measurements. The Pd crystallographic lattice was found to be deformed via an important cont raction of the lattice parameter in the direction perpendicular to the inte rface plane. This deformation was size-dependent, which made this study int eresting from the point of view of size effect study in heterogeneous catal ysis.