Charge exchange processes involving iron ions

Abstract

The experimental and theoretical data which are available for charge exchange processes involving iron ions and neutral H, H2 and He are reviewed and evaluated. A bibliography is given of available data sources, as well as of useful data compilations and review articles. Appropriate scaling laws are presented, and their accuracy estimated for these systems. It is found that, for H and H2 targets, the total charge exchange cross-section data for all Feq+ ions with q ≥ 5 can be represented by a simple analytical formula with an accuracy of 20–25%. A similar formula with an estimated accuracy of 50–80% is given for Feq+ + He charge exchange, based on data for other ionic species, since no iron data are available. The scaling formulae have been further generalized to take into account the dependence of the cross-section on the ionization potential of the neutral target. Electron capture into specific quantum states of the ion is also discussed.