Lifetimes of quasiparticle excitations in 4d transition metals:: Scattering theory and LMTO-RPA-GW approaches -: art. no. 115116

We report the theoretical studies of electron and hole lifetimes in Nb, Mo, Rh, Pd, Ag by means of an ab initio many-body GW method and of a semiempirical scattering-theory approach (STA). The GW approach includes the evaluation of band structures within the local-density approximation linear muffin-tin orbital TB formalism and employment of random-phase approximation in the calculations of the dielectric functions and screened Coulomb interaction. We show that the density-of-states (DOS) convolution model of the STA provides a good approximation to the ab initio averaged lifetimes, the energy dependence of the matrix element being rather unimportant. We discuss the role of the characteristics of electronic structure responsible for the deexcitation of hot electrons as well as the deviations of the ab initio lifetimes from the predictions of the free-electron gas model and the DOS convolution model.