Charge exchange and excitation cross sections at collisions of alpha particles with be-like impurity oxygen ions in a plasma

Abstract

The charge exchange and excitation cross sections at collisions of alphas with O4+(1s 22s 2) impurity atoms in a hot plasma for striking energies E c varying from 20 keV to 2 MeV are determined for the first time. The cross sections are calculated using the method of close-coupling equations with 13 singlet four-electron quasi-molecular states taken as a basis. The partial cross sections of charge transfer to the 1s, 2s, and 2p states of a He+ ion and for O4+(1s 22s 2) → O4+(1s 22lnl’) (n = 2, 3) electronic excitation of an oxygen ion are found. The maximal value of the charge exchange total cross section roughly equals 2.2 × 10−16 cm2 at E c ≈ 0.7 MeV. The excitation total cross section has a maximum of ≈ 7.7 × 10−16 cm2 at E c ≈ 80 keV for single-electron excitation and ≈6.5 × 10−16 cm2 at E c ≈ 0.7 MeV for two-electron excitation.