Single-Electron Capture in Collisions of Carbon Ions with Water Molecules

Single-electron capture in the collisions of carbon ions, Cq+ (q = 1–6), with water molecules is theoretically investigated using the continuum distorted wave-eikonal initial state (CDW-EIS) formalism. The projectile–electron interaction is modeled using three different approaches to account for screening effects: (i) the Green–Sellin–Zachor (GSZ) potential, which combines long-range Coulomb and short-range screening terms; (ii) a modified GSZ-ZPr variant employing an effective radius-dependent nuclear charge; and (iii) the binding energy screening (BES) approximation, which treats the projectile as a rigid Coulomb core. Total cross-sections for single-electron capture are computed over the energy range of 40 keV/u to 10 MeV/u. A detailed analysis is presented as a function of the initial molecular orbital, the final bound state of the captured electron, and the projectile charge state q. The results reveal strong dependencies on orbital binding energies and the degree of projectile ionization. Additionally, of radiobiological interest, the average binding energy for the different projectiles are computed using the presented cross-sections and reported.