Collisional Breakup of High-EnergyH2+Ions

The gas collisional cross sections for breakup of 20.9-MeV ${\mathrm{H}}_2^{+}$ ions into ${\mathrm{H}}^0$+${\mathrm{H}}^{+}$ and ${\mathrm{H}}^{+}$+${\mathrm{H}}^{+}$+$e$ have been measured in ${\mathrm{H}}_2$, He, ${\mathrm{N}}_2$, and Ar. Total dissociation cross sections in the same gases and in the energy range 10 to 65 MeV have been deduced from radial-attenuation measurements on the internal beam of the Berkeley 88-in. cyclotron. These cross sections have also been calculated for each of the ${\mathrm{H}}_2^{+}$ molecular-ion vibrational levels and for an average over the vibrational levels, with an approach proposed by Salpeter. The measured and calculated average cross sections are in good agreement.