COULOMB CHARGING ENERGY FOR ARBITRARY TUNNELING STRENGTH

The Coulomb energy of a small metallic island coupled to an electrode by a tunnel junction is investigated. We employ Monte Carlo simulation s to determine the effective charging energy for arbitrary tunneling s trength. For small tunneling conductance, the data agree with analytic al results based on a perturbative treatment of electron tunneling, wh ile for very strong tunneling recent semiclassical results for large c onductance are approached. The data allow for an identification of the range of validity of various analytical predictions.