Quasi-resonant neutralization of He+ ions at a germanium surface

TL;DR

This paper investigates the quasi-resonant neutralization process of He+ ions at a germanium surface, revealing its high efficiency and significant impact on ion fractions through theoretical analysis of low-energy ion scattering.

Contribution

It introduces a new theoretical approach to quantify the efficiency of quasi-resonant neutralization at a Ge surface, demonstrating its high effectiveness compared to other neutralization mechanisms.

Findings

qRN causes characteristic oscillations in ion fractions.

qRN is two orders of magnitude more efficient than Auger neutralization.

Theoretical methods successfully quantify qRN efficiency.

Abstract

When low-energy He ions are scattered from a Ge surface, the fraction of positive ions exhibits characteristic oscillations as a function of ion energy. These oscillations are caused by quasi-resonant neutralization (qRN), a process which can be observed for materials with a narrow band nearly resonant with the unperturbed He-1s level. In the present manuscript, we employ recently developed theoretical methods to extract quantitative information on the efficiency of qRN. Our evaluation reveals that qRN is a highly efficient process leading to ion fractions two orders of magnitude lower than in systems for which neutralization is only due to Auger processes.