Ground state correlations of jellium metal clusters in local spin-density approximation

The role of S = 1 excitations on the ground state of jellium clusters is analyzed within the random-phase approximation (RPA). The importance of the correlation-energy contribution to the residual interaction in this channel, in order to obtain a consistent description of the cluster electronic states, is stressed. The modification of the single-particle occupation numbers in the RPA ground state is obtained. This modification is found too large when considering only Coulomb exchange contributions to the functional, which clearly points the inadequacy of RPA for this approximate functional and the necessity to include correlation-energy contributions.