On the lifetime of certain excited states of chemisorbed atoms

For the determination of the ESD (electron stimulated desorption) cross section, the deexcitation process of the adsorbate plays an important role. In this paper we calculate the decay rate of the neutral adsorbate which is excited to the antibonding state, taking into account the electron-hole excitations in the metal. A similar technique which was used by Nozieres and Dominicis for the X-ray emission problem is applied for the summation of the diagram expansion. The lifetime of the antibonding state is estimated by the use of a simple model for the electron-hole excitation spectrum.