LONG-DISTANCE AND SHORT-DISTANCE ORDERING OF THE METAL CORES OF GIANTPD CLUSTERS

Three types of metal cores for giant Pd clusters - octahedral or cuboc tahedral, icosahedral (or multiply twinned), and random ones - have be en identified by high resolution electron microscopy. Electron diffrac tion data confirm the fee-like structure for the Pd particles regardle ss of their type; the lattice parameters are very close to those of me tallic palladium. Structural transformations in the Pd clusters are fo und to be accompanied by changes in their catalytic activity and magne tic properties towards the size-induced paramagnetic-diamagnetic trans ition.