Elastic and inelastic processes in H++CH2 collisions between 0.5 and 1.5 keV -: art. no. 032703

Electron capture and direct elastic scattering in collisions of H+ ions with CH2 molecules between 0.5 and 1.5 keV are theoretically investigated. A molecular representation is adopted within a fully quantum-mechanical approach. We consider the following four different molecular configurations for collision dynamics: (I) the proton approaches the C atom along the bisector of the H-C-H bond angle, passing the midpoint of the H-H line, (II) it comes along the same line as in (I), but in the opposite direction, (III) the proton approaches the C atom in the H-C-H plane and perpendicularly to the bisector of the H-C-H bond angle, and (IV) the proton approaches the C atom perpendicularly to the H-C-H plane. Differential cross sections for elastic scattering and electron capture are calculated at 1.5 and 0.5 keV for these different molecular orientations. Total cross sections for these four orientations as well as orientation-averaged total cross sections are also calculated. Our results indicate that electron capture dynamics and corresponding electron-capture cross sections depend substantially on the molecular configuration, thus revealing a strong steric effect.