Dynamics of adsorbate core-hole decay

We have measured the kinetic-energy distribution of the electrons emitted by the radiationless decay of the $C_{1s}$ hole of CO adsorbed on Cu(110) as a function of the energy of the initial photon used to create the core hole. All excited core-hole configurations created by the initial photoionization process decay to the fully screened core-hole state before the core-hole decays. The Auger decay process appears to be ‘‘adiabatic,’’ since both the initial- and final-state configurations are fully screened by charge transfer from the metal.