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(8,9)+ ions with He and H2 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.
