Improved atomic model for charge transfer in multielectron ion-atom collisions at intermediate energies

Electron capture to the $K$ shell of projectiles from the $K$ and other subshells of multielectron target atoms is studied in the intermediate energy region using the single-active-electron approximation and the two-state, two-center atomic eigenfunction expansion method. It is concluded that the theoretical capture cross section is not sensitive to the atomic models used at high collision energies where the projectile velocity $v$ is near or greater than the orbital velocity $v_e$ of the active electron. For $v<\mathrm{}{v}_e$, however, a proper atomic potential such as the Herman-Skillman potential is needed to represent the target atom. The insufficiency of various simple Coulomb model potentials is illustrated. Capture cross sections for a few collision systems are obtained and compared with experimental data when available to illustrate the reliability of the present model.