Fast electron emission in collisions of ions with metal clusters

We present a model to describe the dynamical evolution of the delocalized electrons in a simple metal cluster during and following the passage of a charged particle at intermediate energies. Assuming a mean-field approximation we solve the Vlasov equation by combining the test-particle method and the numerical resolution of the Poisson equation at each time step. This method allows one to use a large number of test particles and to obtain a reliable behavior of the one-body phase-space density over more than 20 fs. The rate and features of fast electron emission are predicted.