Conserving quasiparticle calculations for small metal clusters
Abstract
A novel approach for GW-based calculations of quasiparticle properties for finite systems is presented, in which the screened interaction is obtained directly from a linear response calculation of the density-density correlation function. The conserving nature of our results is shown by explicit evaluation of the f-sum rule. As an application, energy renormalizations and level broadenings are calculated for the closed-shell Na9+ and Na21+ clusters, as well as for Na4. Pronounced improvements of conserving approximations to RPA-level results are obtained.
0