Left panel: thermal rate coefficient for the DR of ${\mathrm{H}}_2^{+}$summed over all five relevant molecular symmetries of the neutral up to an electron temperature of T=4000 K. The colored thin lines show the rate coefficient for the first 30 ro-vibrational levels ($N_i^{+},v_i^{+}$) listed in the legend, while the thick black line shows the thermally averaged rate coefficient by considering the temperature-dependent level population distributions and the ortho-para statistical weights. Right panel: same for HD⁺without ortho-para weights.