Size dependence of bond length and binding energy in palladium and gold clusters

All-electron density functional calculations on a series of highly symmetric palladium clusters up to nuclearity 147 yield an essentially linear correlation between the average bond length and the average coordination. The average binding energy per atom is found to be proportional to the inverse cluster radius and thus mainly determined by the decreasing surface to volume ratio. Comparison to recently obtained results for the corresponding series of gold clusters confirms the wider validity of these size dependence relationships.