David M. Hartley, Ph.D.

A theoretical picture of negative ion formation in adsorbed molecules is presented. Parts of this picture include a tunneling theory of negative ion formation in adsorbed molecules; a theory of lifetime evolution in resonance-assisted molecular desorption; and a theory of the interaction of surface image states with transient atomic negative ions. Analytic models are developed, the results of which illustrate that: an adsorbate molecular ion may be long- or short-lived, compared to its gas-phase lifetime; the equilibrium lifetime, which is commonly measured in short-time dynamical measurements, overestimates the decay rate of adsorbed negative ions which live sufficiently long to induce desorption; and atomic ions may interact with the image states of the surface, thereby perturbing the ion decay rate.