Figure 12.

Comparison of the behavior of the summed excitation rates for the HeHHe⁺ and the HeH⁺ systems in collision with He and H atoms. The dashed thin line reports the calculations from ref (43) for collisions of H atoms with HeH⁺, while the thick solid line reports our earlier calculations from ref (40) on the HeH⁺ collisions with He atoms. The present results for the HeHH⁺ in collision with He atoms are given by the three thin solid lines of different colors.