Double-electron capture by protons from helium

Abstract

The process of ${\mathrm{H}}^{\ensuremath{-}}$ formation as a result of double-electron capture by protons from helium atoms has been investigated by an approximate integral form of the close-coupling formalism considering three atomic states and indistinguishability of electrons. The cross sections have been presented for incident proton energies ranging from 5 keV to 1 MeV and have been compared with the previous experimental and theoretical results. Our cross sections agree fairly well with the experimental results over the range of energy investigated. The total elastic and single-electron capture cross sections and the differential double-electron capture cross sections in the forward direction also have been reported.