Collisions of highly charged Ar-q+ ions (11 less than or equal to q less than or equal to 14) with neutral Ar were investigated at 72q eV laboratory energy. Energy gain spectra were measured at different scattering angles, and relative doubly differential cross sections for the Ar-(q-1+) product were obtained. Odd charge state projectiles are scattered with an energy gain corresponding to a narrow range of Q values, while even charge state projectiles are scattered with energy gains associated with three different groups of Q values. This even-odd variation with projectile charge state seems to be a general feature of Ar-q+ on Ar scattering, but no explanation for this effect is offered at this time. Energy gain spectra measured at different scattering angles were integrated over scattering angles, and the resulting function, proportional to the Q value distribution function, reflects the density of capture states.