  We have performed first-principles calculation of the surface and bulk
wavefunctions of the Cu(111) surface and their hybridization energies to a Co
adatom, including the potential scattering from the Co. By analyzing the
calculated hybridization energies, we found the bulk states dominate the
contribution to the Kondo temperature, in agreement with recent experiments.
Furthermore, we also calculate the tunneling conductance of a scanning
tunneling microscope (STM) and compare our results with recent experiments of
Co impurities in the Cu(111) surface. Good quantitative agreement is found at
short parallel impurity-tip distances (< 6 A). Our results indicate the need
for a new formulation of the problem at larger distances.
