Calculated Properties of Metal Aggregates. II. Silver and Palladium

Abstract

Extended Hückel and CNDO calculations have been made for Ag and Pd aggregates. Bond energy, ionization potential (I.P.), and electron affinity (E.A.) are reported for these particles up to 30 atoms in size. Linear chains are the most stable geometric form of small Ag aggregates, but a transition above 30 atoms is expected at which fcc is more stable. The three-dimensional symmetric geometry is the most stable form of small Pd aggregates. The I.P. and E.A. in both types of geometry converge to a common value at 20 atoms in Ag and at 4 atoms in Pd. These converged values depend upon aggregate geometry, but do approach the work function of bulk metal. Palladium particles are found to have ≈ 0.35 d-band hole per atom, which is close to values reported for bulk metal.