Electron-impact dissociation ofXH2+(X=B, C, N, O, F): Absolute cross sections for production ofXH+andX+fragment ions

Abstract

Absolute cross sections for electron-impact dissociation of $X$H${}_{2}^{+}$ ($X=$ B, C, N, O, F) producing $X$H${}^{+}$ and ${X}^{+}$ ion fragments were measured in the 3- to 100-eV range using a crossed-electron-ion beams technique. Dissociative excitation of BD${}_{2}^{+}$ and CH${}_{2}^{+}$ producing ${\mathrm{B}}^{+}$ and ${\mathrm{C}}^{+}$, respectively, show a propensity toward a two-body dissociation while the remaining species all tend to show a three-body dissociation dynamic. The BD${}^{+}$ and CH${}^{+}$ dissociative excitation channels show a large resonant-type contribution to the cross sections at $~10$ eV. For the ${X}^{+}$ fragment ion production cross sections, a clear dependence on the threshold energy, as it relates to the rate of rise in the cross section above threshold, is observed.