Additivity failure in charge transfer from molecules to bound and continuum states of ∼MeV/uH +, He +,2+ projectiles

Abstract

Additivity of “atomic” cross sections has been observed to fail in electron capture from hydrocarbon molecules to bound and continuum states of 0.6–3.2 MeV H +, He +,2+ projectiles. This failure has been attributed to, and interpreted as, intramolecular secondary collisions that “outscatter” the electrons from their original projectile-centered states. Estimates of the magnitude of this “outscattering” effect from capture-loss calculations or a geometrical scattering model agree quite well with experimental results. These calculations have been used to estimate “atomic” capture cross sections for the oxides and fluorides of C. In the case of bound state capture, these loss processes inject electrons into the continuum; evidence is presented for the observation of these electrons in the continuum cusp, but only in the case of the larger hydrocarbon molecules.