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Abstract

Absolute appearance energies of field-desorbed Li⁺ ions were obtained from mass-to-charge resolved retarding potential analyses of Li⁺ emitted from the first and second Li layer on W(111). Activation energies for Li⁺ field desorption were derived from desorption rate measurements. The field-independent binding energy of Li adatoms has been found from field-dependent Li⁺ appearance and activation energy values, indicating a negligible field-induced charge transfer in the applied field range. We use the cluster embedded in jellium model, based on density-functional theory, to interpret the data by calculating local field enhancements, surface potentials, and activation energies for Li field desorption as a function of field strength and surface coverage as well as geometry.