Convergent close-coupling approach to ion collisions with multielectron targets: Application to collisions
Phys. Rev. A 112, 042816 – Published 27 October, 2025
DOI: https://doi.org/10.1103/xchs-rct2
Abstract
The single-center convergent close-coupling approach to ion-atom collisions is extended to model collisions involving arbitrary multielectron atoms and partially stripped ions. This is accomplished by generating a set of target pseudostates using the configuration-interaction method. The resulting pseudostates are expanded in terms of configuration state functions, constructed using a hybrid of Hartree-Fock and Coulomb-Sturmian spin orbitals. This approach is applied to study antiproton collisions with atomic carbon. We present excitation energies, oscillator strengths, and the dipole polarizability obtained using the target structure model to validate its accuracy. Furthermore, we present results for elastic-scattering, total excitation, and ionization cross sections in the incident energy range between 10 and 1000 keV. State-resolved excitation cross sections for the first few dominant transitions are also presented. Throughout the paper, we compare results obtained using the multicore target structure model with those from a frozen-core one. Generally, we find that a multicore description of the carbon atom target is needed for accurately modeling these collisions.
