CDW-EIS calculations of atomic ionization by bare ions and antiprotons

Abstract

We present \textit{ab initio} calculations of atomic ionization by bare ions and antiprotons within the continuum distorted-wave eikonal initial-state (CDW-EIS) model. The dataset covers atomic targets from H to Kr, impacted by bare ions over a broad range of projectile charges and by antiprotons. Particular attention is given to elements in periods 3 and 4 of the periodic table, which are relevant to pigment analysis and technologically important materials. The resulting subshell-resolved total ionization cross sections are made openly available through an online repository covering a broad range of projectile--target systems, occupied initial subshells, and projectile velocities. We analyze systematic trends in the cross sections, including their dependence on projectile charge and velocity, binding-energy scaling, and charge-sign effects in proton and antiproton impact. To extend the practical coverage of the database, we also develop a neural-network surrogate, CDWEIS-NN, trained on the subset of the database with projectile charge $|Z_\mathrm{P}|\leq 8$. The network interpolates the CDW-EIS results to additional projectile--target systems and impact energies, reproducing both held-out CDW-EIS calculations and the experimental benchmarks considered in this work with satisfactory accuracy.