A new parameterization for copper at the INDO/CI level is presented. Results for excitation energies, ionization potentials, and electron detachment energies are presented for selected copper clusters with up to ten atoms. The parameterization gives improved results for calculations of spectroscopic properties for systems with significant copper-copper interactions, such as clusters and model surfaces. Results for the Ols shakeup of CO attached to Cu(100) model surfaces for the new parameters are compared with experiments and with results obtained using the standard parameters.