s- and d-wave solution of Eliashberg equations with finite bandwidth

In this work, we discuss the results of the direct solution of the Eliashbe rg equations with finite bandwidth, in the cases of s- and d-wave symmetry for the pair wave function and in the presence of scattering from impuritie s. We show that the reduction of the critical temperature T-c due to the fi nite bandwidth depends on the value of the bandwidth itself, but is almost independent of the symmetry of the order parameter. The same happens for th e shape of Z(omega) and Delta(omega). Moreover, we discuss the effect of th e finite bandwidth on the shape of the quasiparticle density of slates. The results clearly indicate that the infinite bandwidth approximation leads t o an underestimation of the electron-boson coupling constant.