Simulation of neutralization processes of Mg+ and Sr+ ions on Au surfaces using the time-dependent Schrödinger equation

We investigated the high neutral fraction (NF) of Mg⁺ ions on Au surfaces through simulations based on solving the simultaneous differential equations derived from the time-dependent Schrödinger equation. Furthermore, we simulated the temperature dependence of the NF by a numerical method derived from the von Neumann equation. The simulation results obtained by considering the Au 6s + 5d band exhibited good agreement with experimental results, suggesting that the high NF of Mg ⁺ ions is related to the interaction between the Au 5d band and the Mg 3s orbital. The calculated temperature dependence of the NF was also in good agreement with the experimental results. By contrast, the NF of Sr⁺ ions on Au surfaces could not be explained simply by a resonant charge transfer mechanism based on the Anderson–Newns model, which implies a contribution from the s–d interaction between the Sr 5s orbital and the Au 5d band.