Elastic and inelastic processes inH++C2H6collisions below the10−keVregime

Abstract

Charge-transfer processes in collisions of ${\mathrm{H}}^{+}$ ions with ${\mathrm{C}}_{2}{\mathrm{H}}_{6}$ molecules are investigated theoretically below $10\text{\ensuremath{-}}\mathrm{keV}$ collision energies within a molecular representation. Converged total as well as differential cross sections are obtained in this energy range within a discrete basis of electronic states computed by ab inito methods. The present collision system suggests that the combination of the Demkov-type and Landau-Zener--type mechanisms primarily governs the scattering dynamics for the flux exit from the initial channel. The present charge-transfer cross sections determined are found to agree very well with all available experimental data below a few keV, but begin to deviate above $3\phantom{\rule{0.3em}{0ex}}\mathrm{keV}$, in which the present results slowly decrease, while measurements stay nearly constant. From the study of the electronic state calculation, we provide some information on fragmented species, which should help shed some light on the fragmentation mechanism and process of ${\mathrm{C}}_{2}{\mathrm{H}}_{6}^{+}$ ions produced after charge transfer. In addition, the vibrational effect of the initial target to charge transfer is examined.