Electromagnetic radiation induced by proton interaction with aluminum nanosheets.

In this work, we employ a single-scale Maxwell-coupled time-dependent density functional theory approach that self-consistently integrates microscopic electron dynamics with full-wave electromagnetic propagation. Taking proton-bombarded aluminum thin films as the model system, we systematically investigate electromagnetic radiation behaviors under both channeling and off-channeling trajectories across a broad range of incident velocities. Our results demonstrate that the charge state of ions within the thin film undergoes dynamic evolution: the spatial distribution of trapped charge transitions gradually from a localized profile to a delocalized one as incident velocity increases. The emission spectra expand from the extremely low-frequency regime to the high-frequency regime with rising incident velocity. At moderate incident velocities, the emission spectra from the front and rear surfaces of the thin film exhibit pronounced asymmetry, a characteristic that can act as a novel indicator for the in situ determination of incident ion velocity. For off-channeling trajectories, near-nuclear collisions are more intense, and both the intensity of the bremsstrahlung continuum and the abundance of ion-excited characteristic peaks are markedly higher than those under channeling trajectories. This work incorporates photon radiation processes into the ab initio energy loss modeling framework, enables quantitative analysis of radiative energy loss, and fills a gap in relevant research. It provides important theoretical support for studies on ion-matter interaction mechanisms in nanostructured materials, optimization of ion beam analysis techniques, and evaluation of radiation damage.