Crossed-beam measurements of differential cross sections for elastic scattering and charge exchange in low-energyAr+-Ar collisions

Differential cross sections for ${\mathrm{Ar}}^{+}$-Ar collisions have been measured at four laboratory energies in the range 2.7-20 eV and laboratory scattering angles from 2 to 90 deg using a crossed-beam apparatus. Data are presented as absolute differential cross sections in the center-of-mass coordinate system as functions of relative translational energy and center-of-mass scattering angle. The data presented should be sufficient to allow rather precise determination of the long-range portion of the ${\mathrm{Ar}}^{+}$-Ar interaction potentials. Preliminary interpretation of the rainbow scattering data gives a dissociation energy $D_e$ for the ${}_{}{}^2{}_{}{}^{}\Sigma _u^{+}{}_{}{}^{}$ state of ${\mathrm{Ar}}_2^{+}$ of 1.40±0.05 eV.