Measurement of n-resolved State-selective Charge Exchange in Ne(8,9)+ Collision with He and H2

Charge exchange between highly charged ions and neutral atoms and molecules has been considered as one of the important mechanisms controlling soft X-ray emissions in many astrophysical objects and environments. However, for modeling charge exchange soft X-ray emission, the data of n- and l-resolved state-selective capture cross sections are often obtained by empirical and semiclassical theory calculations. With a newly built cold target recoil-ion momentum spectroscopy (COLTRIMS) apparatus, we perform a series of measurements of the charge exchange of Ne-(8,Ne-9)+ ions with He and H-2 for collision energy ranging from 1 to 24.75 keV/u. n-resolved state-selective capture cross sections are reported. By comparing the measured state-selective capture cross sections to those calculated by the multichannel Landau-Zener method (MCLZ), it is found that MCLZ calculations are in good agreement with the measurement for the dominant n capture for He target. Furthermore, by using nl-resolved cross sections calculated by MCLZ and applying l distributions commonly used in the astrophysical literature to experimentally derived n-resolved cross sections, we calculate the soft X-ray emissions in the charge exchange between 4 keV/u Ne8+ and He by considering the radiative cascade from the excited Ne7+ ions. Reasonable agreement is found in comparison to the measurement for even and separable models, and MCLZ calculations give results in a better agreement.

Automated summary

The study conducted experimental measurements of charge exchange between Ne-（8，Ne-9）+ ions and He and H-2 using a COLTRIMS apparatus, obtaining n-resolved state-selective capture cross sections and comparing them to calculations by the MCLZ method. The results showed good agreement between experimental and MCLZ calculations for the dominant n capture on He target, providing important data for soft X-ray emission research.