LIFETIME EVOLUTION IN RESONANCE-ASSISTED DESORPTION OF ADSORBED MOLECULES

We have explored how the correlation between the decay rate of a molec ular negative ion and its inter-nuclear coordinates influences the des orption yield produced by electron attachment to a shape resonance of an adsorbed diatomic molecule. An analytic model of resonance-assisted desorption is modified to treat the dynamical evolution of the decay rate. Using this model we demonstrate that the equilibrium lifetime, w hich is commonly measured in short-time dynamical measurements such as high-resolution electron energy loss spectroscopy or inverse photoemi ssion spectroscopy, overestimates the decay rate of those negative ion s which live sufficiently long to induce desorption.