Momentum and density dependence of the ph interaction in continuum RPA calculations with Skyrme forces

We analyse the momentum and density dependence of the ph interaction in self-consistent RPA calculations of electromagnetic reactions with Skyrme forces. First, we calculate the Vph00 and Vph01 spin-isospin components in nuclear matter for an SK3 interaction. At the nuclear surface, they have decreasing values with increasing q-values up to momenta q=3 fm-1. As a second point, we show that the predictions of the 12C(e, e') charge response at 400 MeV/c remain practically unchanged when the zero-range quadratic momentum dependence of the SK3 interaction is replaced by the momentum dependence associated with a Yukawa short-ranged force. (orig.)