Double-electron capture from helium by ions of helium, lithium, carbon, and oxygen

Abstract
Cross sections for double-electron capture from helium atoms by fully stripped ions of lithium, carbon, and oxygen are calculated in the framework of the continuum distorted-wave (CDW) and continuum intermediate-state (CIS) approximations in the energy range of 0.1252.5 MeV/amu. Cross sections are also calculated for α particles as the projectile in the CIS approximation. The results are compared with existing experimental findings. The present calculated results for symmetric and near-symmetric cases show good agreement with the experimental findings. The discrepancies between the calculated and observed values for the asymmetric cases are discussed.