The size dependence of the electronic structure of Pd clusters supported on Al2O3Re(0001)

The size dependence of the electronic structure of Pd clusters deposited on an ordered Al2O3 film on Re(0001) has been studied using angle-resolved photoemission in conjunction with synchrotron radiation. The appearance of dispersion effects along directions both parallel and perpendicular to the substrate surface with increasing cluster size is observed, which is attributed to the formation of crystallites with a preferred orientation and signifies the non-metal to metal transition of the Pd clusters. The transition appears to take place at an estimated average cluster size of approximately 25 Angstrom. (C) 1998 Elsevier Science B.V.