抄録
We have investigated the feature of the screening effect in metal clusters to clarify how it differs from that in bulk metals. For this purpose we employ a jellium sphere as a model for a metal cluster and calculate the change in the electronic states when an extra positive point charge is introduced at its center, by solving the Kohn-Sham equation in the local-density approximation. The screening charge density around the extra charge is estimated by subtracting the charge induced near the cluster surface from the total induced charge density thus calculated. It is found for sodium clusters that, even for small clusters with the number of atoms N=20, 40 and 58, the screening effect is similar to that in the bulk jellium and that the screening charge distributions for larger clusters with N=92 and 198 almost coincide with that in the bulk.
