IONIZATION-ENERGY AND ELECTRON-AFFINITY OF A METAL CLUSTER IN THE STABILIZED JELLIUM MODEL - SIZE EFFECT AND CHARGING LIMIT

We report the first reliable theoretical calculation of the quantum si ze correction c which yields the asymptotic ionization energy I(R) = W + (1/2 + c)/R + O(R-2) of a simple-metal cluster of radius R. Restric ted-variational electronic density profiles are used to evaluate two s ets of expressions for the bulk work function W and quantum size corre ction c: the Koopmans expressions, and the more accurate and profile-i nsensitive Delta SCF expressions. We find c approximate to-0.08 for st abilized (as for ordinary) jellium, and thus for real simple metals. W e present parameters from which the density profiles may be reconstruc ted for a wide range of cluster sizes, including the planar surface. W e also discuss how many excess electrons can be bound by a neutral clu ster of given size. Within a continuum picture, the criterion for tota l-energy stability of a negatively charged cluster is less stringent t han that for existence of a self-consistent solution. (C) 1998 America n Institute of Physics.