Velocity dependence of free-ion production in K(np)-SF6collisions: Internal-to-translational energy transfer

The velocity dependence of the rate constant for free-ion production via the Rydberg electron-transfer reaction K(np)+${\mathrm{SF}}_6$→${\mathrm{K}}^{+}$+${\mathrm{SF}}_6^{\mathrm{-}\mathrm{*}}$ has been investigated at intermediate n. The data provide evidence of a postattachment interaction between the product ions in which internal energy from the ${\mathrm{SF}}_6^{\mathrm{-}\mathrm{*}}$ ion is converted into translational energy. A similar conclusion is reached from measurements of the velocity and angular distributions of the product ${\mathrm{K}}^{+}$ ions.