  Charge exchange is an important process for the modeling of X-ray spectra
obtained by the Chandra, XMM-Newton, and Suzaku X-ray observatories, as well as
the anticipated Astro-H mission. The understanding of the observed X-ray
spectra produced by many astrophysical environments is hindered by the current
incompleteness of available atomic and molecular data -- especially for charge
exchange. Here, we implement a streamlined program set that applies quantum
defect methods and the Landau-Zener theory to generate total, n-resolved, and
nlS-resolved cross sections for any given projectile ion/ target charge
exchange collision. Using this data in a cascade model for X-ray emission,
theoretical spectra for such systems can be predicted. With these techniques,
Fe25+ and Fe26+ charge exchange collisions with H, He, H2, N2, H2O, and CO are
studied for single electron capture. These systems have been selected as they
illustrate computational difficulties for high projectile charges. Further, Fe
XXV and Fe XXVI emission lines have been detected in the Galactic center and
Galactic ridge. Theoretical X-ray spectra for these collision systems are
compared to experimental data generated by an electron beam ion trap study.
Several l- distribution models have been tested for Fe25+ and Fe26+ single
electron capture. Such analysis suggests that commonly used l-distribution
models struggle to accurately reflect the true distribution of electron capture
as understood by more advanced theoretical methods.
