Single-electron capture from helium targets by heavy nuclei of charges 1–7

Abstract

Single-electron capture by multiply charged nuclei from helium atoms is studied by means of the prior form of the four-body boundary-corrected continuum intermediate state (BCIS-4B) method. Computations concern total cross sections for the state-selective (Qnlm) and state-summed (Qnl,Qn,QΣ) populations at 20–3000 keV/amu. These refer to the collisions of the type AZP++He(1s2)→A(ZP−1)+(nlm)+He+(1s). Here, the projectile AZP+ covers the ions H+, He2+, Li3+, Be4+, B5+, C6+ and N7+. The reported findings are tabulated for each value of the quantum numbers {n,l,m}. The maximum values nmax of the principal quantum number n are 4 (H+, He2+, Li3+), 5 (Be4+), 6 (B5+) and 7 (C6+, N7+). The sum over all the n states is truncated by selecting an appropriate cutoff value nmax and by subsequently applying the Oppenheimer n−3 scaling rule to approximately include the contributions from n>nmax. The obtained results for QΣ and for some final n−specific states favorably describe the corresponding experimental data. This qualifies the prior form of the BCIS-4B method for further useful applications in several interdisciplinary fields, including astrophysics, thermonuclear fusion, plasma physics and ion therapy in medicine.