  Electron-capture rates at different density and temperature conditions are
evaluated for a set of pf-shell nuclei representative of the constituents in
presupernova formations. The nuclear structure part of the problem is described
within a quasiparticle random-phase approximation based on a deformed Skyrme
Hartree-Fock selfconsistent mean field with pairing correlations and residual
interactions in particle-hole and particle-particle channels. The energy
distributions of the Gamow-Teller strength are evaluated and compared to
benchmark shell-model calculations and experimental data extracted from
charge-exchange reactions. The model dependence of the weak rates are discussed
and the various sensitivities to both density and temperature are analyzed.
