A theory is presented which accounts for lsquo;lsquo;giantrsquo;rsquo; enhancements in electron stimulated desorption (ESD) yields from adsorbatehyphen;covered surfaces if the incident electrons become trapped in a shape or Feshbach resonance associated with the adsorbate. The resulting temporary negative ion is displaced inwards towards the surface as a result of the force provided by the image screening charge. Upon reneutralization, the lsquo;lsquo;desorbatersquo;rsquo; can be returned high on the dissociative repulsive wall of the neutralhyphen;surface potential curve. This process has been modeled within the context of semiclassical Gaussian wave packet dynamics. Recent observations of such giant enhancements in the ESD yields for the system O(a)/Pd(111) are explained in terms of this model, and an atomic physics basis for the resonance in atomic oxygen is proposed.
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