Electron-impact dissociative excitation and ionization of dihydride cations XH$_{2}^{+}$ (X=B, C, N, O, F)

Absolute cross sections for electron-impact dissociation of XH$_{2}^{+}$ (X=B, C, N, O, F) cations forming XH$^{+}$ and X$^{+}$ ion fragments were measured in the 3-100 eV range using a crossed electron-ion beams technique at Oak Ridge National Laboratory. This electron energy range covers both dissociative excitation and ionization of these species. Large, resonant-type contributions are observed in the dissociative excitation channels of CH$_{2}^{+}$ --$>$ CH$^{+}$ and BH$_{2}^{+}$ --$>$ BH$^{+}$, however, the other species do not exhibit such an enhancement to the dissociative excitation cross sections.