Target-Projectile Interaction model for describing spectral line emission following charge exchange at low interaction energies

We present a model for describing the x-ray line emission following charge exchange at low interaction energies that includes the Stark effect on energy levels with high principal quantum number due to target-projectile interaction (TPI). We test the TPI model against laboratory measurements of x-ray line emission following the charge exchange between bare and H-like iron ions and several neutral targets (H₂, H, N₂, and He) in an electron beam ion trap. While standard spectral models of charge exchange fail in reproducing key spectral features, the TPI model provides a good fit to both K-shell and L-shell emission observed with a high-resolution micro-calorimeter spectrometer. Our analysis also shows that the collision energy for charge exchange reactions in the trap is typically lower than previously inferred from the ion temperature measured during ion generation.