Generalized independent-atom-model approach for net ionization of molecules by multiply-charged-heavy-ion impact
Phys. Rev. A 112, 052820 – Published 17 November, 2025
DOI: https://doi.org/10.1103/8nst-41jd
Abstract
The previously applied independent-atom model (IAM) for highly charged ion-molecule collisions which implemented the suppression of multiple ionization and capture on the basis of geometric overlaps of cross-sectional areas representing ion-atom cross sections using a pixel-counting method (PCM) [H. J. Lüdde, T. Kalkbrenner, M. Horbatsch, and T. Kirchner, Phys. Rev. A 101, 062709 (2020)] is extended to incorporate the possibility of multiple collisions within the molecule. This is accomplished on the basis of estimated mean free paths for sequential projectile-atom collisions. The IAM-PCM was demonstrated to be successful in describing proton-molecule collisions and moderately-charged ion impact at high collision energies. The new model does agree with these results, but has important consequences for highly charged projectiles, providing cross sections larger than those of IAM-PCM, but still well below the simple additivity rule results.
