Resonant Charge Transfer in Scattering of Alkali Ions on Metal Surfaces: Theoretical Modeling Based on Anderson‒Newnes Hamiltonian

Abstract

The process of negative ionization of hydrogen on surfaces with a low work function plays an important role in the creation of highly efficient sources of negative ion beams used in accelerators, mass spectrometry, thermonuclear installations, and other high-tech areas. Increasing the efficiency of negative ion sources requires an in-depth understanding of the mechanisms of resonant charge transfer. In this study, the problem of electron exchange between an H⁰ atomic particle and a cesium-coated W(110) surface was considered and the negative ionization process was studied. The problem was described using the Anderson–Newnes theory, which allows one to take into account the dynamics of hybridization of the electron states of the adsorbate and the surface. Contrary to expectations based on the shifted Fermi sphere model, an increase in the parallel component of the particle velocity led to a decrease in the probability of H^– formation. This discrepancy with the predictions of traditional models emphasizes the need to take into account the dynamic aspects of electron exchange and the initial conditions of the system.