First-principles calculation of the plasmon resonance and of the reflectance spectrum of silver in the GW approximation -: art. no. 115101

We show that the position and width of the plasmon resonance in silver are correctly predicted by ab initio calculations including self-energy effects within the GW approximation. Unlike in simple metals and semiconductors, quasiparticle corrections play a key role and are essential to obtain electron energy loss in quantitative agreement with the experimental data. The sharp reflectance minimum at 3.92 eV, that cannot be reproduced within density-functional theory (DFT) in the local-density approximation (LDA), is also well described within GW. The present results solve two unsettled drawbacks of linear-response calculations for silver.