Kinetic electron emission from metal surfaces induced by impact of slow ions

Available experimental data on the kinetic electron emission from surfaces of metals induced by impact of very slow ions indicate that the dependence of the total electron yield on the projectile velocity, the projectile atomic number and the metal work function can be described by a simple analytical formula. A precise theoretical description of this emission process based on averaging over all trajectories and properly taking into account electron excitations in non-ideal solids is currently not feasible because of the complexity of excitation processes. The presented simple phenomenological model, which uses free electron metal substrates, simulates the experimental observations quite well. As discussed in the paper, the model requires ad hoc assumptions regarding the electron excitation. A high spatial localization of the excitation and ensuing electron–electron interaction in the impact zone are the essential features of the model.